Clinical Focus

  • Diagnostic Radiology

Academic Appointments

  • Professor - Med Center Line, Radiology

Administrative Appointments

  • Associate Chair, Stanford University School of Medicine - Radiology (2004 - Present)

Professional Education

  • Residency:University of British Columbia Radiology Residency (1992) Canada
  • Internship:St Michael's Hospital Postgraduate Medical Education (1987) Canada
  • Medical Education:University of British Columbia Radiology Residency (1986) Canada
  • Fellowship:L'Hopital Pitie-Salpetrieoe (1993) France
  • Board Certification: Diagnostic Radiology, American Board of Radiology (1992)
  • Board Certification: Diagnostic Radiology, Royal College of Physicians and Surgeons of Canada (1992)
  • BSc, McGill University, Biochemistry (1982)

Research & Scholarship

Current Research and Scholarly Interests

High-resolution computed tomography of the thorax,, particularly its application in the setting of acute lung disease in the immunocompromised host; quantitative assessment of abnormalities, using spiral CT; and enhancement characteristics of lung cancers on, CT and MRI

Clinical Trials

  • Pulmonary Interstitial Lymphography in Early Stage Lung Cancer Not Recruiting

    The stereotactic body radiation therapy (SBRT) procedure is an emerging alternative to the standard treatment for early stage non-small cell lung cancer (NSCLC), typically lobectomy with lymphadenectomy. This procedure (lobectomy) does not fulfill the medical need as many patients are poor operative candidates or decline surgery. This study assesses the feasibility of stereotactic body radiation therapy (SBRT) as a tool to produce therapeutically useful computed tomography (CT) scans, using standard water-soluble iodinated compounds as the contrast agents.

    Stanford is currently not accepting patients for this trial. For more information, please contact Laura Gable, (650) 736 - 0798.

    View full details


2019-20 Courses


All Publications

  • [18F] FDG Positron Emission Tomography (PET) Tumor and Penumbra Imaging Features Predict Recurrence in Non-Small Cell Lung Cancer. Tomography (Ann Arbor, Mich.) Mattonen, S. A., Davidzon, G. A., Bakr, S., Echegaray, S., Leung, A. N., Vasanawala, M., Horng, G., Napel, S., Nair, V. S. 2019; 5 (1): 145?53


    We identified computational imaging features on 18F-fluorodeoxyglucose positron emission tomography (PET) that predict recurrence/progression in non-small cell lung cancer (NSCLC). We retrospectively identified 291 patients with NSCLC from 2 prospectively acquired cohorts (training, n = 145; validation, n = 146). We contoured the metabolic tumor volume (MTV) on all pretreatment PET images and added a 3-dimensional penumbra region that extended outward 1 cm from the tumor surface. We generated 512 radiomics features, selected 435 features based on robustness to contour variations, and then applied randomized sparse regression (LASSO) to identify features that predicted time to recurrence in the training cohort. We built Cox proportional hazards models in the training cohort and independently evaluated the models in the validation cohort. Two features including stage and a MTV plus penumbra texture feature were selected by LASSO. Both features were significant univariate predictors, with stage being the best predictor (hazard ratio [HR] = 2.15 [95% confidence interval (CI): 1.56-2.95], P < .001). However, adding the MTV plus penumbra texture feature to stage significantly improved prediction (P = .006). This multivariate model was a significant predictor of time to recurrence in the training cohort (concordance = 0.74 [95% CI: 0.66-0.81], P < .001) that was validated in a separate validation cohort (concordance = 0.74 [95% CI: 0.67-0.81], P < .001). A combined radiomics and clinical model improved NSCLC recurrence prediction. FDG PET radiomic features may be useful biomarkers for lung cancer prognosis and add clinical utility for risk stratification.

    View details for PubMedID 30854452

  • A radiogenomic dataset of non-small cell lung cancer. Scientific data Bakr, S., Gevaert, O., Echegaray, S., Ayers, K., Zhou, M., Shafiq, M., Zheng, H., Benson, J. A., Zhang, W., Leung, A. N., Kadoch, M., D Hoang, C., Shrager, J., Quon, A., Rubin, D. L., Plevritis, S. K., Napel, S. 2018; 5: 180202


    Medical image biomarkers of cancer promise improvements in patient care through advances in precision medicine. Compared to genomic biomarkers, image biomarkers provide the advantages of being non-invasive, and characterizing a heterogeneous tumor in its entirety, as opposed to limited tissue available via biopsy. We developed a unique radiogenomic dataset from a Non-Small Cell Lung Cancer (NSCLC) cohort of 211 subjects. The dataset comprises Computed Tomography (CT), Positron Emission Tomography (PET)/CT images, semantic annotations of the tumors as observed on the medical images using a controlled vocabulary, and segmentation maps of tumors in the CT scans. Imaging data are also paired with results of gene mutation analyses, gene expression microarrays and RNA sequencing data from samples of surgically excised tumor tissue, and clinical data, including survival outcomes. This dataset was created to facilitate the discovery of the underlying relationship between tumor molecular and medical image features, as well as the development and evaluation of prognostic medical image biomarkers.

    View details for PubMedID 30325352

  • Invited Commentary on "Updated Fleischner Society Guidelines for Managing Incidental Pulmonary Nodules". Radiographics : a review publication of the Radiological Society of North America, Inc Leung, A. N. 2018; 38 (5): 1350?51

    View details for PubMedID 30207942

  • Computed Tomography Features associated With the Eighth Edition TNM Stage Classification for Thymic Epithelial Tumors JOURNAL OF THORACIC IMAGING Padda, S. K., Terrone, D., Tian, L., Khuong, A., Neal, J. W., Riess, J. W., Berry, M. F., Hoang, C. D., Burt, B. M., Leung, A. N., Schwartz, E. J., Shrager, J. B., Wakelee, H. A. 2018; 33 (3): 176?83


    The eighth edition of the TNM classification of malignant tumors for the first time includes an official staging system for thymic epithelial tumors (TETs) recognized by the American Joint Committee on Cancer (AJCC) and the Union for International Cancer Control (UICC). Staging is critical for the management of TETs, and determining stage accurately from imaging has the potential to improve clinical outcomes. We examine preoperative computed tomography (CT) characteristics of TETs associated with AJCC/UICC pathologic TNM stage.In this retrospective study, patients were included if they met all the following criteria: (1) diagnosis of TET, (2) had primary curative intent surgery performed at Stanford University, and (3) had available preoperative CT imaging for review. Tumor pathology was staged according to the eighth edition TNM classification. Fifteen CT scan features were examined from each patient case according to the International Thymic Malignancy Interest Group standard report terms in a blinded manner. A Lasso-regularized multivariate model was used to produce a weighted scoring system predictive of pathologic TNM stage.Examining the 54 patients included, the following CT characteristics were associated with higher pathologic TNM stage when using the following scoring system: elevated hemidiaphragm (score of 6), vascular endoluminal invasion (score of 6), pleural nodule (score of 2), lobulated contour (score of 2), and heterogeneous internal density (score of 1). Area under the receiver operating characteristic curve was 0.76.TETs with clearly invasive or metastatic features seen on CT are associated with having higher AJCC/UICC pathologic TNM stage, as expected. However, features of lobulated contour and heterogeneous internal density are also associated with higher stage disease. These findings need to be validated in an independent cohort.

    View details for PubMedID 29219888

  • Lung Cancer Screening, Version 3.2018 JOURNAL OF THE NATIONAL COMPREHENSIVE CANCER NETWORK Wood, D. E., Kazerooni, E. A., Baum, S. L., Eapen, G. A., Ettinger, D. S., Hou, L., Jackman, D. M., Klippenstein, D., Kumar, R., Lackner, R. P., Leard, L. E., Lennes, I. T., Leung, A. C., Makani, S. S., Massion, P. P., Mazzone, P., Merritt, R. E., Meyers, B. F., Midthun, D. E., Pipavath, S., Pratt, C., Reddy, C., Reid, M. E., Rotter, A. J., Sachs, P. B., Schabath, M. B., Schiebler, M. L., Tong, B. C., Travis, W. D., Wei, B., Yang, S. C., Gregory, K. M., Hughes, M. 2018; 16 (4): 412?41


    Lung cancer is the leading cause of cancer-related mortality in the United States and worldwide. Early detection of lung cancer is an important opportunity for decreasing mortality. Data support using low-dose computed tomography (LDCT) of the chest to screen select patients who are at high risk for lung cancer. Lung screening is covered under the Affordable Care Act for individuals with high-risk factors. The Centers for Medicare & Medicaid Services (CMS) covers annual screening LDCT for appropriate Medicare beneficiaries at high risk for lung cancer if they also receive counseling and participate in shared decision-making before screening. The complete version of the NCCN Guidelines for Lung Cancer Screening provides recommendations for initial and subsequent LDCT screening and provides more detail about LDCT screening. This manuscript focuses on identifying patients at high risk for lung cancer who are candidates for LDCT of the chest and on evaluating initial screening findings.

    View details for DOI 10.6004/jnccn.2018.0020

    View details for Web of Science ID 000429534300011

    View details for PubMedID 29632061

  • Presence of Even a Small Ground-Glass Component in Lung Adenocarcinoma Predicts Better Survival CLINICAL LUNG CANCER Berry, M. F., Gao, R., Kunder, C. A., Backhus, L., Khuong, A., Kadoch, M., Leung, A., Shrager, J. 2018; 19 (1): E47?E51


    While lepidic-predominant lung adenocarcinomas are known to have better outcomes than similarly sized solid tumors, the impact of smaller noninvasive foci within predominantly solid tumors is less clearly characterized. We tested the hypothesis that lung adenocarcinomas with even a small ground-glass opacity (GGO) component have a better prognosis than otherwise similar pure solid (PS) adenocarcinomas.The maximum total and solid-component diameters were determined by preoperative computed tomography in patients who underwent lobar or sublobar resection of clinical N0 adenocarcinomas without induction therapy between May 2003 and August 2013. Survival between patients with PS tumors (0% GGO) or tumors with a minor ground-glass (MGG) component (1%-25% GGO) was compared by Kaplan-Meier and Cox analyses.A total of 123 patients met the inclusion criteria, comprising 54 PS (44%) and 69 MGG (56%) whose mean ground-glass component was 18 7%. The solid component tumor diameter was not significantly different between the groups (2.3 1.2 cm vs. 2.5 1.3 cm, P= .2). Upstaging to pN1-2 was more common for the PS group (13% [7/54] vs. 3% [2/69], P= .04), but the distribution of pathologic stage was not significantly different between the groups (PS 76% stage I [41/54] vs. MGG 80% stage I [55/69], P= .1). Having a MGG component was associated with markedly better survival in both univariate analysis (MGG 5-year overall survival 86.7% vs. PS 64.5%, P= .001) and multivariable survival analysis (hazard ratio, 0.30, P= .01).Patients with resected cN0 lung adenocarcinoma who have even a small GGO component have markedly better survival than patients with PS tumors, which may have implications for both treatment and surveillance strategies.

    View details for PubMedID 28743420

  • An Analysis of Lung Cancer Screening Beliefs and Practice Patterns for Community Providers Compared to Academic Providers. Cancer control : journal of the Moffitt Cancer Center Khairy, M., Duong, D. K., Shariff-Marco, S., Cheng, I., Jain, J., Balakrishnan, A., Liu, L., Gupta, A., Chandramouli, R., Hsing, A., Leung, A., Singh, B., Nair, V. S. 2018; 25 (1): 1073274818806900


    Despite guidelines recommending annual low-dose computed tomography (LDCT) screening for lung cancer, uptake remains low due to the perceived complexity of initiating and maintaining a clinical program-problems that likely magnify in underserved populations. We conducted a survey of community providers at Federally Qualified Health Centers (FQHCs) in Santa Clara County, California, to evaluate provider-related factors that affect adherence. We then compared these findings to academic providers' (APs) LDCT screening knowledge, behaviors, and attitudes at an academic referral center in the same county. The 4 FQHCs enrolled care for 80 000 patients largely of minority descent and insured by Medi-Cal. Of the 75 FQHC providers (FQHCPs), 36 (48%) completed the survey. Of the 36 providers, 8 (22%) knew screening criteria. Fifteen (42%) FQHCPs discussed LDCT screening with patients. Compared to 36 APs, FQHCPs were more concerned about harms, false positives, discussion time, patient apathy, insurance coverage, and a lack of expertise for screening and follow-up. Yet, more FQHCPs thought screening was effective (27 [75%] of 36) compared to APs ( P = .0003). In conclusion, provider knowledge gaps are greater and barriers are different for community clinics caring for underserved populations compared to their academic counterparts, but practical and scalable solutions exist to enhance adoption.

    View details for PubMedID 30375235

  • Non-Small Cell Lung Cancer Radiogenomics Map Identifies Relationships between Molecular and Imaging Phenotypes with Prognostic Implications. Radiology Zhou, M., Leung, A., Echegaray, S., Gentles, A., Shrager, J. B., Jensen, K. C., Berry, G. J., Plevritis, S. K., Rubin, D. L., Napel, S., Gevaert, O. 2018; 286 (1): 307?15


    Purpose To create a radiogenomic map linking computed tomographic (CT) image features and gene expression profiles generated by RNA sequencing for patients with non-small cell lung cancer (NSCLC). Materials and Methods A cohort of 113 patients with NSCLC diagnosed between April 2008 and September 2014 who had preoperative CT data and tumor tissue available was studied. For each tumor, a thoracic radiologist recorded 87 semantic image features, selected to reflect radiologic characteristics of nodule shape, margin, texture, tumor environment, and overall lung characteristics. Next, total RNA was extracted from the tissue and analyzed with RNA sequencing technology. Ten highly coexpressed gene clusters, termed metagenes, were identified, validated in publicly available gene-expression cohorts, and correlated with prognosis. Next, a radiogenomics map was built that linked semantic image features to metagenes by using the t statistic and the Spearman correlation metric with multiple testing correction. Results RNA sequencing analysis resulted in 10 metagenes that capture a variety of molecular pathways, including the epidermal growth factor (EGF) pathway. A radiogenomic map was created with 32 statistically significant correlations between semantic image features and metagenes. For example, nodule attenuation and margins are associated with the late cell-cycle genes, and a metagene that represents the EGF pathway was significantly correlated with the presence of ground-glass opacity and irregular nodules or nodules with poorly defined margins. Conclusion Radiogenomic analysis of NSCLC showed multiple associations between semantic image features and metagenes that represented canonical molecular pathways, and it can result in noninvasive identification of molecular properties of NSCLC. Online supplemental material is available for this article.

    View details for PubMedID 28727543

  • Evaluating the impact of varied compliance to lung cancer screening recommendations using a microsimulation model CANCER CAUSES & CONTROL Han, S. S., Erdogan, S., Toumazis, I., Leung, A., Plevritis, S. K. 2017; 28 (9): 947?58


    The US preventive services task force (USPSTF) recently recommended that individuals aged 55-80 with heavy smoking history be annually screened by low-dose computed tomography (LDCT), thereby extending the stopping age from 74 to 80 compared to the national lung screening trial (NLST) entry criterion. This decision was made partly with model-based analyses from cancer intervention and surveillance modeling network (CISNET), which assumed perfect compliance to screening.As part of CISNET, we developed a microsimulation model for lung cancer (LC) screening and calibrated and validated it using data from NLST and the prostate, lung, colorectal, and ovarian cancer screening trial (PLCO), respectively. We evaluated population-level outcomes of the lifetime screening program recommended by the USPSTF by varying screening compliance levels.Validation using PLCO shows that our model reproduces observed PLCO outcomes, predicting 884 LC cases [Expected(E)/Observed(O)=0.99; CI 0.92-1.06] and 563 LC deaths (E/O=0.94 CI 0.87-1.03) in the screening arm that has an average compliance rate of 87.9% over four annual screening rounds. We predict that perfect compliance to the USPSTF recommendation saves 501 LC deaths per 100,000 persons in the 1950 U.S. birth cohort; however, assuming that compliance behaviors extrapolated and varied from PLCO reduces the number of LC deaths avoided to 258, 230, and 175 as the average compliance rate over 26 annual screening rounds changes from 100 to 46, 39, and 29%, respectively.The implementation of the USPSTF recommendation is expected to contribute to a reduction in LC deaths, but the magnitude of the reduction will likely be heavily influenced by screening compliance.

    View details for PubMedID 28702814

    View details for PubMedCentralID PMC5880208

  • Patient and primary care provider attitudes and adherence towards lung cancer screening at an academic medical center. Preventive medicine reports Duong, D. K., Shariff-Marco, S., Cheng, I., Naemi, H., Moy, L. M., Haile, R., Singh, B., Leung, A., Hsing, A., Nair, V. S. 2017; 6: 17-22


    Low dose CT (LDCT) for lung cancer screening is an evidence-based, guideline recommended, and Medicare approved test but uptake requires further study. We therefore conducted patient and provider surveys to elucidate factors associated with utilization. Patients referred for LDCT at an academic medical center were questioned about their attitudes, knowledge, and beliefs on lung cancer screening. Adherent patients were defined as those who met screening eligibility criteria and completed a LDCT. Referring primary care providers within this same medical system were surveyed in parallel about their practice patterns, attitudes, knowledge and beliefs about screening. Eighty patients responded (36%), 48 of whom were adherent. Among responders, non-Hispanic patients (p=0.04) were more adherent. Adherent respondents believed that CT technology is accurate and early detection is useful, and they trusted their providers. A majority of non-adherent patients (79%) self-reported an intention to obtain a LDCT in the future. Of 36 of 87 (41%) responding providers, only 31% knew the correct lung cancer screening eligibility criteria, which led to a 37% inappropriate referral rate from 2013 to 2015. Yet, 75% had initiated lung cancer screening discussions, 64% thought screening was at least moderately effective, and 82% were interested in learning more of the 33 providers responding to these questions. Overall, patients were motivated and providers engaged to screen for lung cancer by LDCT. Non-adherent patient "procrastinators" were motivated to undergo screening in the future. Additional follow through on non-adherence may enhance screening uptake, and raising awareness for screening eligibility through provider education may reduce inappropriate referrals.

    View details for DOI 10.1016/j.pmedr.2017.01.012

    View details for PubMedID 28210538

    View details for PubMedCentralID PMC5304233

  • Prediction of EGFR and KRAS mutation in non-small cell lung cancer using quantitative 18F FDG-PET/CT metrics. Oncotarget Minamimoto, R., Jamali, M., Gevaert, O., Echegaray, S., Khuong, A., Hoang, C. D., Shrager, J. B., Plevritis, S. K., Rubin, D. L., Leung, A. N., Napel, S., Quon, A. 2017


    This study investigated the relationship between epidermal growth factor receptor (EGFR) and Kirsten rat sarcoma viral oncogene homolog (KRAS) mutations in non-small-cell lung cancer (NSCLC) and quantitative FDG-PET/CT parameters including tumor heterogeneity. 131 patients with NSCLC underwent staging FDG-PET/CT followed by tumor resection and histopathological analysis that included testing for the EGFR and KRAS gene mutations. Patient and lesion characteristics, including smoking habits and FDG uptake parameters, were correlated to each gene mutation. Never-smoker (P < 0.001) or low pack-year smoking history (p = 0.002) and female gender (p = 0.047) were predictive factors for the presence of the EGFR mutations. Being a current or former smoker was a predictive factor for the KRAS mutations (p = 0.018). The maximum standardized uptake value (SUVmax) of FDG uptake in lung lesions was a predictive factor of the EGFR mutations (p = 0.029), while metabolic tumor volume and total lesion glycolysis were not predictive. Amongst several tumor heterogeneity metrics included in our analysis, inverse coefficient of variation (1/COV) was a predictive factor (p < 0.02) of EGFR mutations status, independent of metabolic tumor diameter. Multivariate analysis showed that being a never-smoker was the most significant factor (p < 0.001) for the EGFR mutations in lung cancer overall. The tumor heterogeneity metric 1/COV and SUVmax were both predictive for the EGFR mutations in NSCLC in a univariate analysis. Overall, smoking status was the most significant factor for the presence of the EGFR and KRAS mutations in lung cancer.

    View details for DOI 10.18632/oncotarget.17782

    View details for PubMedID 28538213

  • Left Atrium Maximal Axial Cross-Sectional Area is a Specific Computed Tomographic Imaging Biomarker of World Health Organization Group 2 Pulmonary Hypertension. Journal of thoracic imaging Jivraj, K., Bedayat, A., Sung, Y. K., Zamanian, R. T., Haddad, F., Leung, A. N., Rosenberg, J., Guo, H. H. 2017; 32 (2): 121-126


    Left heart disease is associated with left atrial enlargement and is a common cause of pulmonary hypertension (PH). We investigated the relationship between left atrium maximal axial cross-sectional area (LA-MACSA), as measured on chest computed tomography (CT), and PH due to left heart disease (World Health Organization group 2) in patients with right heart catheterization-proven PH.A total of 165 patients with PH who had undergone right heart catheterization with pulmonary artery pressure and pulmonary capillary wedge pressure (PCWP) measurements and nongated chest CTs were included. LA-MACSA, LA anterior-posterior, and LA transverse measurements were independently obtained using the hand-drawn region-of-interest and distance measurement tools on standard PACS by 2 blinded cardiothoracic radiologists. Nonparametric statistical analyses and receiver operating characteristic curve were performed.Forty-three patients had group 2 PH (PCWP>15 mm Hg), and 122 had nongroup 2 PH (PCWP?15 mm Hg). Median LA-MACSA was significantly different between the group 2 PH and nongroup 2 PH patients (2312 vs. 1762 mm, P<0.001). Interobserver concordance correlation for LA-MACSA was high at 0.91 (P<0.001). At a threshold of 2400 mm, LA-MACSA demonstrated 93% specificity for classifying group 2 PH (area under the curve, 0.73; P<0.001).LA-MACSA is a readily obtainable and reproducible measurement of left atrial enlargement on CT and can distinguish between group 2 and nongroup 2 PH with high specificity.

    View details for DOI 10.1097/RTI.0000000000000252

    View details for PubMedID 28009778

  • Thoracic Imaging Features of Legionnaire's Disease INFECTIOUS DISEASE CLINICS OF NORTH AMERICA Mittal, S., Singh, A. P., Gold, M., Leung, A. N., Haramati, L. B., Katz, D. S. 2017; 31 (1): 43-+


    Imaging examinations are often performed in patients with Legionnaires' disease. The literature to date has documented that the imaging findings in this disorder are relatively nonspecific, and it is therefore difficult to prospectively differentiate legionella pneumonia from other forms of pneumonia, and from other noninfectious thoracic processes. Through a review of clinical cases and the literature, our objective is for the reader to gain a better understanding of the spectrum of radiographic manifestations of Legionnaires' disease.

    View details for PubMedID 28159175

  • Predictive radiogenomics modeling of EGFR mutation status in lung cancer SCIENTIFIC REPORTS Gevaert, O., Echegaray, S., Khuong, A., Hoang, C. D., Shrager, J. B., Jensen, K. C., Berry, G. J., Guo, H. H., Lau, C., Plevritis, S. K., Rubin, D. L., Napel, S., Leung, A. N. 2017; 7


    Molecular analysis of the mutation status for EGFR and KRAS are now routine in the management of non-small cell lung cancer. Radiogenomics, the linking of medical images with the genomic properties of human tumors, provides exciting opportunities for non-invasive diagnostics and prognostics. We investigated whether EGFR and KRAS mutation status can be predicted using imaging data. To accomplish this, we studied 186 cases of NSCLC with preoperative thin-slice CT scans. A thoracic radiologist annotated 89 semantic image features of each patient's tumor. Next, we built a decision tree to predict the presence of EGFR and KRAS mutations. We found a statistically significant model for predicting EGFR but not for KRAS mutations. The test set area under the ROC curve for predicting EGFR mutation status was 0.89. The final decision tree used four variables: emphysema, airway abnormality, the percentage of ground glass component and the type of tumor margin. The presence of either of the first two features predicts a wild type status for EGFR while the presence of any ground glass component indicates EGFR mutations. These results show the potential of quantitative imaging to predict molecular properties in a non-invasive manner, as CT imaging is more readily available than biopsies.

    View details for DOI 10.1038/srep41674

    View details for PubMedID 28139704

  • Adaptation of Mycobacterium tuberculosis to Impaired Host Immunity in HIV-Infected Patients JOURNAL OF INFECTIOUS DISEASES Walter, N. D., de Jong, B. C., Garcia, B. J., Dolganov, G. M., Worodria, W., Byanyima, P., Musisi, E., Huang, L., Chan, E. D., Van, T. T., Antonio, M., Ayorinde, A., Kato-Maeda, M., Nahid, P., Leung, A. M., Yen, A., Fingerlin, T. E., Kechris, K., Strong, M., Voskuil, M. I., Davis, J. L., Schoolnik, G. K. 2016; 214 (8): 1205-1211


    It is unknown whether immunosuppression influences the physiologic state of Mycobacterium tuberculosis in vivo. We evaluated the impact of host immunity by comparing M. tuberculosis and human gene transcription in sputum between human immunodeficiency virus (HIV)-infected and uninfected patients with tuberculosis.We collected sputum specimens before treatment from Gambians and Ugandans with pulmonary tuberculosis, revealed by positive results of acid-fast bacillus smears. We quantified expression of 2179 M. tuberculosis genes and 234 human immune genes via quantitative reverse transcription-polymerase chain reaction. We summarized genes from key functional categories with significantly increased or decreased expression.A total of 24 of 65 patients with tuberculosis were HIV infected. M. tuberculosis DosR regulon genes were less highly expressed among HIV-infected patients with tuberculosis than among HIV-uninfected patients with tuberculosis (Gambia, P < .0001; Uganda, P = .037). In profiling of human genes from the same sputa, HIV-infected patients had 3.4-fold lower expression of IFNG (P = .005), 4.9-fold higher expression of ARG1 (P = .0006), and 3.4-fold higher expression of IL10 (P = .0002) than in HIV-uninfected patients with tuberculosis.M. tuberculosis in HIV-infected patients had lower expression of the DosR regulon, a critical metabolic and immunomodulatory switch induced by NO, carbon monoxide, and hypoxia. Our human data suggest that decreased DosR expression may result from alternative pathway activation of macrophages, with consequent decreased NO expression and/or by poor granuloma formation with consequent decreased hypoxic stress.

    View details for DOI 10.1093/infdis/jiw364

    View details for PubMedID 27534685

  • A Rapid Segmentation-Insensitive 'Digital Biopsy' Method for Radiomic Feature Extraction; Method and Pilot Study Using CT Images of Non-Small Cell Lung Cancer Tomography Echegaray, S., Nair, V., Kadoch, M., Leung, A., Rubin, D., Gevaert, O., Napel Sandy , et al 2016; 2 (4): 283?94


    Quantitative imaging approaches compute features within images' regions of interest. Segmentation is rarely completely automatic, requiring time-consuming editing by experts. We propose a new paradigm, called "digital biopsy," that allows for the collection of intensity- and texture-based features from these regions at least 1 order of magnitude faster than the current manual or semiautomated methods. A radiologist reviewed automated segmentations of lung nodules from 100 preoperative volume computed tomography scans of patients with non-small cell lung cancer, and manually adjusted the nodule boundaries in each section, to be used as a reference standard, requiring up to 45 minutes per nodule. We also asked a different expert to generate a digital biopsy for each patient using a paintbrush tool to paint a contiguous region of each tumor over multiple cross-sections, a procedure that required an average of <3 minutes per nodule. We simulated additional digital biopsies using morphological procedures. Finally, we compared the features extracted from these digital biopsies with our reference standard using intraclass correlation coefficient (ICC) to characterize robustness. Comparing the reference standard segmentations to our digital biopsies, we found that 84/94 features had an ICC >0.7; comparing erosions and dilations, using a sphere of 1.5-mm radius, of our digital biopsies to the reference standard segmentations resulted in 41/94 and 53/94 features, respectively, with ICCs >0.7. We conclude that many intensity- and texture-based features remain consistent between the reference standard and our method while substantially reducing the amount of operator time required.

    View details for DOI 10.18383/j.tom.2016.00163

    View details for PubMedCentralID PMC5466872

  • Diameter of Solid Tumor Component Alone Should be Used to Establish T Stage in Lung Adenocarcinoma ANNALS OF SURGICAL ONCOLOGY Burt, B. M., Leung, A. N., Yanagawa, M., Chen, W., Groth, S. S., Hoang, C. D., Nair, V. S., Shrager, J. B. 2015; 22: S1318-S1323


    The computed tomographic (CT) appearance of so-called ground glass components within lung adenocarcinomas correlate with noninvasive tumor histology, and solid radiographic components correlate with invasive histology. We hypothesized thatT stage might be more accurately applied by considering the solid component nodule diameter rather than total nodule diameter.We identified 74 patients with a solitary lung adenocarcinoma who underwent resection without receiving neoadjuvant therapy. Maximum total diameter and solid diameter of the nodules were measured on CT scans performed within 3 months of surgery. Cox proportional hazard modeling and Kaplan-Meier analyses were performed to determine whether total nodule diameter or solid component diameter was more predictive of overall survival.Thirty-three patients (45%) had a solid nodule and 41 patients (55%) had a part-solid nodule. Most patients were white (59%) and female (69%), and 42% had never smoked. Seventy-four percent underwent lobectomy and 23% sublobar resection. Sixty-six percent had pathologic stage I disease, 22% stage II, and 12% stage IIIA. MeanSD total and solid nodule diameters were 32.117.5 and 24.818.0mm, respectively (p=0.01). Among patients with part-solid nodules, multivariate modeling incorporating significant univariate predictors of survival (age, gender, procedure, N descriptor) revealed that maximum solid diameter was associated with overall survival (hazard ratio 1.4, p=0.01), while maximum total diameter was not.In a largely non-Asian cohort undergoing resection for adenocarcinoma, radiographic diameter of the solid component of a part-solid lesion on CT predicts overall survival better than total lesion diameter. These data provide further evidence to support altering the T descriptor for lung adenocarcinoma for part-solid nodules.

    View details for DOI 10.1245/s10434-015-4780-0

    View details for Web of Science ID 000367288100136

  • Diameter of Solid Tumor Component Alone Should be Used to Establish T Stage in Lung Adenocarcinoma. Annals of surgical oncology Burt, B. M., Leung, A. N., Yanagawa, M., Chen, W., Groth, S. S., Hoang, C. D., Nair, V. S., Shrager, J. B. 2015; 22: 1318-1323


    The computed tomographic (CT) appearance of so-called ground glass components within lung adenocarcinomas correlate with noninvasive tumor histology, and solid radiographic components correlate with invasive histology. We hypothesized thatT stage might be more accurately applied by considering the solid component nodule diameter rather than total nodule diameter.We identified 74 patients with a solitary lung adenocarcinoma who underwent resection without receiving neoadjuvant therapy. Maximum total diameter and solid diameter of the nodules were measured on CT scans performed within 3 months of surgery. Cox proportional hazard modeling and Kaplan-Meier analyses were performed to determine whether total nodule diameter or solid component diameter was more predictive of overall survival.Thirty-three patients (45%) had a solid nodule and 41 patients (55%) had a part-solid nodule. Most patients were white (59%) and female (69%), and 42% had never smoked. Seventy-four percent underwent lobectomy and 23% sublobar resection. Sixty-six percent had pathologic stage I disease, 22% stage II, and 12% stage IIIA. MeanSD total and solid nodule diameters were 32.117.5 and 24.818.0mm, respectively (p=0.01). Among patients with part-solid nodules, multivariate modeling incorporating significant univariate predictors of survival (age, gender, procedure, N descriptor) revealed that maximum solid diameter was associated with overall survival (hazard ratio 1.4, p=0.01), while maximum total diameter was not.In a largely non-Asian cohort undergoing resection for adenocarcinoma, radiographic diameter of the solid component of a part-solid lesion on CT predicts overall survival better than total lesion diameter. These data provide further evidence to support altering the T descriptor for lung adenocarcinoma for part-solid nodules.

    View details for DOI 10.1245/s10434-015-4780-0

    View details for PubMedID 26228108

  • Computed Tomography (CT) Characteristics Associated with the Proposed IASLC/ITMIG TNM Pathologic Staging System for Thymoma Padda, S. K., Terrone, D., Khuong, A., Tian, L., Neal, J. W., Riess, J. W., Berry, M., Leung, A. N., Schwartz, E. J., Shrager, J. B., Wakelee, H. A. ELSEVIER SCIENCE INC. 2015: S196
  • Automated classification of usual interstitial pneumonia using regional volumetric texture analysis in high-resolution computed tomography. Investigative radiology Depeursinge, A., Chin, A. S., Leung, A. N., Terrone, D., Bristow, M., Rosen, G., Rubin, D. L. 2015; 50 (4): 261-267


    We propose a novel computational approach for the automated classification of classic versus atypical usual interstitial pneumonia (UIP).Thirty-three patients with UIP were enrolled in this study. They were classified as classic versus atypical UIP by a consensus of 2 thoracic radiologists with more than 15 years of experience using the American Thoracic Society evidence-based guidelines for computed tomography diagnosis of UIP. Two cardiothoracic fellows with 1 year of subspecialty training provided independent readings. The system is based on regional characterization of the morphological tissue properties of lung using volumetric texture analysis of multiple-detector computed tomography images. A simple digital atlas with 36 lung subregions is used to locate texture properties, from which the responses of multidirectional Riesz wavelets are obtained. Machine learning is used to aggregate and to map the regional texture attributes to a simple score that can be used to stratify patients with UIP into classic and atypical subtypes.We compared the predictions on the basis of regional volumetric texture analysis with the ground truth established by expert consensus. The area under the receiver operating characteristic curve of the proposed score was estimated to be 0.81 using a leave-one-patient-out cross-validation, with high specificity for classic UIP. The performance of our automated method was found to be similar to that of the 2 fellows and to the agreement between experienced chest radiologists reported in the literature. However, the errors of our method and the fellows occurred on different cases, which suggests that combining human and computerized evaluations may be synergistic.Our results are encouraging and suggest that an automated system may be useful in routine clinical practice as a diagnostic aid for identifying patients with complex lung disease such as classic UIP, obviating the need for invasive surgical lung biopsy and its associated risks.

    View details for DOI 10.1097/RLI.0000000000000127

    View details for PubMedID 25551822

    View details for PubMedCentralID PMC4355184

  • Predicting adenocarcinoma recurrence using computational texture models of nodule components in lung CT MEDICAL PHYSICS Depeursinge, A., Yanagawa, M., Leung, A. N., Rubin, D. L. 2015; 42 (4): 2054-2063


    To investigate the importance of presurgical computed tomography (CT) intensity and texture information from ground-glass opacities (GGO) and solid nodule components for the prediction of adenocarcinoma recurrence.For this study, 101 patients with surgically resected stage I adenocarcinoma were selected. During the follow-up period, 17 patients had disease recurrence with six associated cancer-related deaths. GGO and solid tumor components were delineated on presurgical CT scans by a radiologist. Computational texture models of GGO and solid regions were built using linear combinations of steerable Riesz wavelets learned with linear support vector machines (SVMs). Unlike other traditional texture attributes, the proposed texture models are designed to encode local image scales and directions that are specific to GGO and solid tissue. The responses of the locally steered models were used as texture attributes and compared to the responses of unaligned Riesz wavelets. The texture attributes were combined with CT intensities to predict tumor recurrence and patient hazard according to disease-free survival (DFS) time. Two families of predictive models were compared: LASSO and SVMs, and their survival counterparts: Cox-LASSO and survival SVMs.The best-performing predictive model of patient hazard was associated with a concordance index (C-index) of 0.81 0.02 and was based on the combination of the steered models and CT intensities with survival SVMs. The same feature group and the LASSO model yielded the highest area under the receiver operating characteristic curve (AUC) of 0.8 0.01 for predicting tumor recurrence, although no statistically significant difference was found when compared to using intensity features solely. For all models, the performance was found to be significantly higher when image attributes were based on the solid components solely versus using the entire tumors (p < 3.08 10(-5)).This study constitutes a novel perspective on how to interpret imaging information from CT examinations by suggesting that most of the information related to adenocarcinoma aggressiveness is related to the intensity and morphological properties of solid components of the tumor. The prediction of adenocarcinoma relapse was found to have low specificity but very high sensitivity. Our results could be useful in clinical practice to identify patients for which no recurrence is expected with a very high confidence using a presurgical CT scan only. It also provided an accurate estimation of the risk of recurrence after a given duration t from surgical resection (i.e., C-index = 0.81 0.02).

    View details for DOI 10.1118/1.4916088

    View details for Web of Science ID 000352273200059

    View details for PubMedID 25832095

    View details for PubMedCentralID PMC4385100

  • Lung Cancer Screening, Version 1.2015 Featured Updates to the NCCN Guidelines JOURNAL OF THE NATIONAL COMPREHENSIVE CANCER NETWORK Wood, D. E., Kazerooni, E., Baum, S. L., Dransfield, M. T., Eapen, G. A., Ettinger, D. S., Hou, L., Jackman, D. M., Klippenstein, D., Kumar, R., Lackner, R. P., Leard, L. E., Leung, A. N., Makani, S. S., Massion, P. P., Meyers, B. F., Otterson, G. A., Peairs, K., Pipavath, S., Pratt-Pozo, C., Reddy, C., Reid, M. E., Rotter, A. J., Sachs, P. B., Schabath, M. B., Sequist, L. V., Tong, B. C., Travis, W. D., Yang, S. C., Gregory, K. M., Hughes, M. 2015; 13 (1): 23-34


    The NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Lung Cancer Screening provide recommendations for selecting individuals for lung cancer screening, and for evaluation and follow-up of nodules found during screening, and are intended to assist with clinical and shared decision-making. These NCCN Guidelines Insights focus on the major updates to the 2015 NCCN Guidelines for Lung Cancer Screening, which include a revision to the recommendation from category 2B to 2A for one of the high-risk groups eligible for lung cancer screening. For low-dose CT of the lung, the recommended slice width was revised in the table on "Low-Dose Computed Tomography Acquisition, Storage, Interpretation, and Nodule Reporting."

    View details for Web of Science ID 000347793200007

    View details for PubMedID 25583767

  • Professionalism in radiology. Journal of thoracic imaging Leung, A. N. 2014; 29 (5): 284-288


    Professionalism has been described as the "basis of medicine's contract with society." This article reviews the foundational principles of medical professionalism and, more specifically, defines the nature and scope of radiologists' responsibilities to patients. In the face of ongoing changes in the environment of medical practice, maintenance of professionalism is an adaptive challenge that will require successful practitioners to be open to and actively engaged in continuous learning and self-improvement. Imaging 3.0 is a change process developed by the American College of Radiology to help radiologists redefine and reprioritize their professional activities as the discipline transitions from a volume-based to value-based specialty.

    View details for DOI 10.1097/RTI.0000000000000100

    View details for PubMedID 25160596

  • Lung Volume Reduction After Stereotactic Ablative Radiation Therapy of Lung Tumors: Potential Application to Emphysema INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS Binkley, M. S., Shrager, J. B., Leung, A. N., Popat, R., Trakul, N., Atwood, T. F., Chaudhuri, A., Maxim, P. G., Diehn, M., Loo, B. W. 2014; 90 (1): 216-223


    Lung volume reduction surgery (LVRS) improves dyspnea and other outcomes in selected patients with severe emphysema, but many have excessive surgical risk for LVRS. We analyzed the dose-volume relationship for lobar volume reduction after stereotactic ablative radiation therapy (SABR) of lung tumors, hypothesizing that SABR could achieve therapeutic volume reduction if applied in emphysema.We retrospectively identified patients treated from 2007 to 2011 who had SABR for 1 lung tumor, pre-SABR pulmonary function testing, and ?6 months computed tomographic (CT) imaging follow-up. We contoured the treated lobe and untreated adjacent lobe(s) on CT before and after SABR and calculated their volume changes relative to the contoured total (bilateral) lung volume (TLV). We correlated lobar volume reduction with the volume receiving high biologically effective doses (BED, ?/? = 3).27 patients met the inclusion criteria, with a median CT follow-up time of 14 months. There was no grade ?3 toxicity. The median volume reduction of the treated lobe was 4.4% of TLV (range, -0.4%-10.8%); the median expansion of the untreated adjacent lobe was 2.6% of TLV (range, -3.9%-11.6%). The volume reduction of the treated lobe was positively correlated with the volume receiving BED ?60 Gy (r(2)=0.45, P=.0001). This persisted in subgroups determined by high versus low pre-SABR forced expiratory volume in 1 second, treated lobe CT emphysema score, number of fractions, follow-up CT time, central versus peripheral location, and upper versus lower lobe location, with no significant differences in effect size between subgroups. Volume expansion of the untreated adjacent lobe(s) was positively correlated with volume reduction of the treated lobe (r(2)=0.47, P<.0001).We identified a dose-volume response for treated lobe volume reduction and adjacent lobe compensatory expansion after lung tumor SABR, consistent across multiple clinical parameters. These data serve to inform our ongoing prospective trial of stereotactic ablative volume reduction (SAVR) for severe emphysema in poor candidates for LVRS.

    View details for DOI 10.1016/j.ijrobp.2014.05.025

    View details for Web of Science ID 000341456500029

  • COMPUTED TOMOGRAPHY (CT) CHARACTERISTICS ASSOCIATED WITH MASAOKA-KOGA PATHOLOGIC STAGE IN THYMOMA Padda, S., Terrone, D., Khuong, A., Tian, L., Neal, J. W., Riess, J. W., Hoang, C. D., Burt, B. M., Leung, A. N., Shrager, J. B., Wakelee, H. A. LIPPINCOTT WILLIAMS & WILKINS. 2014: S222
  • ACR-STR practice parameter for the performance and reporting of lung cancer screening thoracic computed tomography (CT): 2014 (Resolution 4). Journal of thoracic imaging Kazerooni, E. A., Austin, J. H., Black, W. C., Dyer, D. S., Hazelton, T. R., Leung, A. N., McNitt-Gray, M. F., Munden, R. F., Pipavath, S. 2014; 29 (5): 310-316

    View details for DOI 10.1097/RTI.0000000000000097

    View details for PubMedID 24992501

  • Prognostic importance of volumetric measurements in stage I lung adenocarcinoma. Radiology Yanagawa, M., Tanaka, Y., Leung, A. N., Morii, E., Kusumoto, M., Watanabe, S., Watanabe, H., Inoue, M., Okumura, M., Gyobu, T., Ueda, K., Honda, O., Sumikawa, H., Johkoh, T., Tomiyama, N. 2014; 272 (2): 557-567


    Purpose To perform volumetric analysis of stage I lung adenocarcinomas by using an automated computer program and to determine value of volumetric computed tomographic (CT) measurements associated with prognostic factors and outcome. Materials and Methods Consecutive patients (n = 145) with stage I lung adenocarcinoma who underwent surgery after preoperative chest CT were enrolled. By using volumetric automated computer-assisted analytic program, nodules were classified into three subgroups: pure ground glass, part solid, or solid. Total tumor volume, solid tumor volume, and percentage of solid volume of each cancer were calculated after eliminating vessel components. One radiologist measured the longest diameter of the solid tumor component and of total tumor with their ratio, which was defined as solid proportion. The value of these quantitative data by examining associations with pathologic prognostic factors and outcome measures (disease-free survival and overall survival) were analyzed with logistic regression and Cox proportional hazards regression models, respectively. Significant parameters identified at univariate analysis were included in the multiple analyses. Results All 22 recurrences occurred in patients with nodules classified as part solid or solid. Multiple logistic regression analysis revealed that percentage of solid volume of 63% or greater was an independent indicator associated with pleural invasion (P = .01). Multiple Cox proportional hazards regression analysis revealed that percentage of solid volume of 63% or greater was a significant indicator of lower disease-free survival (hazard ratio, 18.45 [95% confidence interval: 4.34, 78.49]; P < .001). Both solid tumor volume of 1.5 cm(3) or greater and percentage of solid volume of 63% or greater were significant indicators of decreased overall survival (hazard ratio, 5.92 and 9.60, respectively [95% confidence interval: 1.17, 30.33 and 1.17, 78.91, respectively]; P = .034 and .036, respectively). Conclusion Two volumetric measurements (solid volume, ?1.5 cm(3); percentage of solid volume, ?63%) were found to be independent indicators associated with increased likelihood of recurrence and/or death in patients with stage I adenocarcinoma. RSNA, 2014.

    View details for DOI 10.1148/radiol.14131903

    View details for PubMedID 24708191

  • Ultra-low-dose CT of the Lung: Effect of Iterative Reconstruction Techniques on Image Quality. Academic radiology Yanagawa, M., Gyobu, T., Leung, A. N., Kawai, M., Kawata, Y., Sumikawa, H., Honda, O., Tomiyama, N. 2014; 21 (6): 695-703


    To compare quality of ultra-low-dose thin-section computed tomography (CT) images of the lung reconstructed using model-based iterative reconstruction (MBIR) and adaptive statistical iterative reconstruction (ASIR) to filtered back projection (FBP) and to determine the minimum tube current-time product on MBIR images by comparing to standard-dose FBP images.Ten cadaveric lungs were scanned using 120 kVp and four different tube current-time products (8, 16, 32, and 80 mAs). Thin-section images were reconstructed using MBIR, three ASIR blends (30%, 60%, and 90%), and FBP. Using the 8-mAs data, side-to-side comparison of the four iterative reconstruction image sets to FBP was performed by two independent observers who evaluated normal and abnormal findings, subjective image noise, streak artifact, and overall image quality. Image noise was also measured quantitatively. Subsequently, 8-, 16-, and 32-mAs MBIR images were compared to standard-dose FBP images. Comparisons of image sets were analyzed using the Wilcoxon signed rank test with Bonferroni correction.At 8 mAs, MBIR images were significantly better (P < .005) than other reconstruction techniques except in evaluation of interlobular septal thickening. Each set of low-dose MBIR images had significantly lower (P < .001) subjective and objective noise and streak artifacts than standard-dose FBP images. Conspicuity and visibility of normal and abnormal findings were not significantly different between 16-mAs MBIR and 80-mAs FBP images except in identification of intralobular reticular opacities.MBIR imaging shows higher overall quality with lower noise and streak artifacts than ASIR or FBP imaging, resulting in nearly 80% dose reduction without any degradations of overall image quality.

    View details for DOI 10.1016/j.acra.2014.01.023

    View details for PubMedID 24713541

  • CT patterns of fungal pulmonary infections of the lung: Comparison of standard-dose and simulated low-dose CT (vol 81, pg 2860, 2012) EUROPEAN JOURNAL OF RADIOLOGY Christe, A., Lin, M. C., Yen, A. C., Hallett, R. L., Roychoudhury, K., Schmitzberger, F., Fleischmann, D., Leung, A. N., Rubin, G. D., Vock, P., Roos, J. E. 2013; 82 (11): 2067
  • CT patterns of fungal pulmonary infections of the lung: Comparison of standard-dose and simulated low-dose CT EUROPEAN JOURNAL OF RADIOLOGY Christe, A., Lin, M. C., Yen, A. C., Hallett, R. L., Roychoudhury, K., Schmitzberger, F., Fleischmann, D., Leung, A. N., Rubin, G. D., Vock, P., Roos, J. E. 2012; 81 (10): 2860-2866


    To assess the effect of radiation dose reduction on the appearance and visual quantification of specific CT patterns of fungal infection in immuno-compromised patients.Raw data of thoracic CT scans (64 0.75 mm, 120 kVp, 300 reference mAs) from 41 consecutive patients with clinical suspicion of pulmonary fungal infection were collected. In 32 patients fungal infection could be proven (median age of 55.5 years, range 35-83). A total of 267 cuboids showing CT patterns of fungal infection and 27 cubes having no disease were reconstructed at the original and 6 simulated tube currents of 100, 40, 30, 20, 10, and 5 reference mAs. Eight specific fungal CT patterns were analyzed by three radiologists: 76 ground glass opacities, 42 ground glass nodules, 51 mixed, part solid, part ground glass nodules, 36 solid nodules, 5 lobulated nodules, 6 spiculated nodules, 14 cavitary nodules, and 37 foci of air-space disease. The standard of reference was a consensus subjective interpretation by experts whom were not readers in the study.The mean sensitivity and standard deviation for detecting pathological cuboids/disease using standard dose CT was 0.91 0.07. Decreasing dose did not affect sensitivity significantly until the lowest dose level of 5 mAs (0.87 0.10, p=0.012). Nodular pattern discrimination was impaired below the dose level of 30 reference mAs: specificity for fungal 'mixed nodules' decreased significantly at 20, 10 and 5 reference mAs (p<0.05). At lower dose levels, classification drifted from 'solid' to 'mixed nodule', although no lesion was missed.Our simulation data suggest that tube current levels can be reduced from 300 to 30 reference mAs without impairing the diagnostic information of specific CT patterns of pulmonary fungal infections.

    View details for DOI 10.1016/j.ejrad.2011.06.059

    View details for Web of Science ID 000308079700067

    View details for PubMedID 21835569

  • Non-Small Cell Lung Cancer: Identifying Prognostic Imaging Biomarkers by Leveraging Public Gene Expression Microarray Data-Methods and Preliminary Results RADIOLOGY Gevaert, O., Xu, J., Hoang, C. D., Leung, A. N., Xu, Y., Quon, A., Rubin, D. L., Napel, S., Plevritis, S. K. 2012; 264 (2): 387-396


    To identify prognostic imaging biomarkers in non-small cell lung cancer (NSCLC) by means of a radiogenomics strategy that integrates gene expression and medical images in patients for whom survival outcomes are not available by leveraging survival data in public gene expression data sets.A radiogenomics strategy for associating image features with clusters of coexpressed genes (metagenes) was defined. First, a radiogenomics correlation map is created for a pairwise association between image features and metagenes. Next, predictive models of metagenes are built in terms of image features by using sparse linear regression. Similarly, predictive models of image features are built in terms of metagenes. Finally, the prognostic significance of the predicted image features are evaluated in a public gene expression data set with survival outcomes. This radiogenomics strategy was applied to a cohort of 26 patients with NSCLC for whom gene expression and 180 image features from computed tomography (CT) and positron emission tomography (PET)/CT were available.There were 243 statistically significant pairwise correlations between image features and metagenes of NSCLC. Metagenes were predicted in terms of image features with an accuracy of 59%-83%. One hundred fourteen of 180 CT image features and the PET standardized uptake value were predicted in terms of metagenes with an accuracy of 65%-86%. When the predicted image features were mapped to a public gene expression data set with survival outcomes, tumor size, edge shape, and sharpness ranked highest for prognostic significance.This radiogenomics strategy for identifying imaging biomarkers may enable a more rapid evaluation of novel imaging modalities, thereby accelerating their translation to personalized medicine.

    View details for DOI 10.1148/radiol.12111607

    View details for PubMedID 22723499

  • Lung Cancer Screening JOURNAL OF THE NATIONAL COMPREHENSIVE CANCER NETWORK Wood, D. E., Eapen, G. A., Ettinger, D. S., Hou, L., Jackman, D., Kazerooni, E., Klippenstein, D., Lackner, R. P., Leard, L., Leung, A. N., Massion, P. P., Meyers, B. F., Munden, R. F., Otterson, G. A., Peairs, K., Pipavath, S., Pratt-Pozo, C., Reddy, C., Reid, M. E., Rotter, A. J., Schabath, M. B., Sequist, L. V., Tong, B. C., Travis, W. D., Unger, M., Yang, S. C. 2012; 10 (2): 240-265

    View details for Web of Science ID 000300067400008

    View details for PubMedID 22308518

  • Integrating medical images and transcriptomic data in non-small cell lung cancer Gevaert, O., Xu, J., Hoang, C., Leung, A., Quon, A., Rubin, D., Napel, S., Plevritis, S. AMER ASSOC CANCER RESEARCH. 2011
  • Case 166: Metastatic Left Pulmonary Artery Sarcoma RADIOLOGY Mittra, E. S., Iagaru, A. H., Leung, A. N. 2011; 258 (2): 645-648

    View details for DOI 10.1148/radiol.10082169

    View details for Web of Science ID 000286653700037

    View details for PubMedID 21273527

  • Yield of diagnostic procedures for invasive fungal infections in neutropenic febrile patients with chest computed tomography abnormalities MYCOSES Ho, D. Y., Lin, M., Schaenman, J., Rosso, F., Leung, A. N., Coutre, S. E., Sista, R. R., Montoya, J. G. 2011; 54 (1): 59-70


    Haematological patients with neutropenic fever are frequently evaluated with chest computed tomography (CT) to rule out invasive fungal infections (IFI). We retrospectively analysed data from 100 consecutive patients with neutropenic fever and abnormal chest CT from 1998 to 2005 to evaluate their chest CT findings and the yield of diagnostic approaches employed. For their initial CTs, 79% had nodular opacities, with 24.1% associated with the halo sign. Other common CT abnormalities included pleural effusions (48%), ground glass opacities (37%) and consolidation (31%). The CT findings led to a change in antifungal therapy in 54% of the patients. Fifty-six patients received diagnostic procedures, including 46 bronchoscopies, 25 lung biopsies and seven sinus biopsies, with a diagnostic yield for IFI of 12.8%, 35.0% and 83.3%, respectively. In conclusion, chest CT plays an important role in the evaluation of haematological patients with febrile neutropenia and often leads to a change in antimicrobial therapy. Pulmonary nodules are the most common radiological abnormality. Sinus or lung biopsies have a high-diagnostic yield for IFI as compared to bronchoscopy. Patients with IFI may not have sinus/chest symptoms, and thus, clinicians should have a low threshold for performing sinus/chest imaging, and if indicated and safe, a biopsy of the abnormal areas.

    View details for DOI 10.1111/j.1439-0507.2009.01760.x

    View details for PubMedID 19793207

  • Epoprostenol-associated pneumonitis: Diagnostic use of a T-cell proliferation assay JOURNAL OF HEART AND LUNG TRANSPLANTATION Kudelko, K. T., Nadeau, K., Leung, A. N., Liu, J., Haddad, F., Zamanian, R. T., Perez, V. D. 2010; 29 (9): 1071-1075


    We describe a case of severe drug-induced interstitial pneumonitis in a woman with idiopathic pulmonary arterial hypertension receiving epoprostenol confirmed by a drug T-cell proliferation assay. Proliferation assays were completed in our patient and in a healthy control. Isolated T cells were incubated with CD3-depleted peripheral blood mononuclear cells and then stimulated to proliferate with (3)H-thymidine in the presence of epoprostenol, other prostanoid analogs, and controls. A significant (p < 0.001) T-cell proliferation response occurred in our patient in the presence of epoprostenol alone. There was a trend towards an increased T-cell response to treprostinil but this was statistically insignificant. There was no significant T-cell response to the diluent alone, normal saline, iloprost, or alprostadil. There was no significant proliferation to any drug in the healthy control. Hence, a drug T-cell proliferation assay confirmed that epoprostenol can rarely incite a profound inflammatory response in the pulmonary interstitium.

    View details for DOI 10.1016/j.healun.2010.04.023

    View details for Web of Science ID 000281494800016

    View details for PubMedCentralID PMC2926193

  • Epoprostenol-associated pneumonitis: diagnostic use of a T-cell proliferation assay. journal of heart and lung transplantation Kudelko, K. T., Nadeau, K., Leung, A. N., Liu, J., Haddad, F., Zamanian, R. T., de Jesus Perez, V. 2010; 29 (9): 1071-1075


    We describe a case of severe drug-induced interstitial pneumonitis in a woman with idiopathic pulmonary arterial hypertension receiving epoprostenol confirmed by a drug T-cell proliferation assay. Proliferation assays were completed in our patient and in a healthy control. Isolated T cells were incubated with CD3-depleted peripheral blood mononuclear cells and then stimulated to proliferate with (3)H-thymidine in the presence of epoprostenol, other prostanoid analogs, and controls. A significant (p < 0.001) T-cell proliferation response occurred in our patient in the presence of epoprostenol alone. There was a trend towards an increased T-cell response to treprostinil but this was statistically insignificant. There was no significant T-cell response to the diluent alone, normal saline, iloprost, or alprostadil. There was no significant proliferation to any drug in the healthy control. Hence, a drug T-cell proliferation assay confirmed that epoprostenol can rarely incite a profound inflammatory response in the pulmonary interstitium.

    View details for DOI 10.1016/j.healun.2010.04.023

    View details for PubMedID 20627625

    View details for PubMedCentralID PMC2926193

  • Computer-aided detection (CAD) of lung nodules in CT scans: radiologist performance and reading time with incremental CAD assistance EUROPEAN RADIOLOGY Roos, J. E., Paik, D., Olsen, D., Liu, E. G., Chow, L. C., Leung, A. N., Mindelzun, R., Choudhury, K. R., Naidich, D. P., Napel, S., Rubin, G. D. 2010; 20 (3): 549-557


    The diagnostic performance of radiologists using incremental CAD assistance for lung nodule detection on CT and their temporal variation in performance during CAD evaluation was assessed.CAD was applied to 20 chest multidetector-row computed tomography (MDCT) scans containing 190 non-calcified > or =3-mm nodules. After free search, three radiologists independently evaluated a maximum of up to 50 CAD detections/patient. Multiple free-response ROC curves were generated for free search and successive CAD evaluation, by incrementally adding CAD detections one at a time to the radiologists' performance.The sensitivity for free search was 53% (range, 44%-59%) at 1.15 false positives (FP)/patient and increased with CAD to 69% (range, 59-82%) at 1.45 FP/patient. CAD evaluation initially resulted in a sharp rise in sensitivity of 14% with a minimal increase in FP over a time period of 100 s, followed by flattening of the sensitivity increase to only 2%. This transition resulted from a greater prevalence of true positive (TP) versus FP detections at early CAD evaluation and not by a temporal change in readers' performance. The time spent for TP (9.5 s +/- 4.5 s) and false negative (FN) (8.4 s +/- 6.7 s) detections was similar; FP decisions took two- to three-times longer (14.4 s +/- 8.7 s) than true negative (TN) decisions (4.7 s +/- 1.3 s).When CAD output is ordered by CAD score, an initial period of rapid performance improvement slows significantly over time because of non-uniformity in the distribution of TP CAD output and not to a changing reader performance over time.

    View details for DOI 10.1007/s00330-009-1596-y

    View details for Web of Science ID 000274544800005

    View details for PubMedID 19760237

  • Best Cases from the AFIP Fatal 2009 Influenza A (H1N1) Infection, Complicated by Acute Respiratory Distress Syndrome and Pulmonary Interstitial Emphysema RADIOGRAPHICS Guo, H. H., Sweeney, R. T., Regula, D., Leung, A. N. 2010; 30 (2): 327-333

    View details for DOI 10.1148/rg.302095213

    View details for Web of Science ID 000275622400003

    View details for PubMedID 20068001

  • Cystic Fibrosis HRCT Scores Correlate Strongly With Pseudomonas Infection PEDIATRIC PULMONOLOGY Robinson, T. E., Leung, A. N., Chen, X., Moss, R. B., Emond, M. J. 2009; 44 (11): 1107-1117


    In order to establish a valid surrogate outcome measure, it must be shown that the outcome measure (chest HRCT scores in cystic fibrosis [CF] patients) demonstrates strong statistical association with established endpoints of disease, such as Pseudomonas aeruginosa (Pa) airway acquisition, acute exacerbations, or mortality.We estimated and tested the association between Pa infection status (Pa+ vs. Pa-) and baseline chest HRCT scores in 25 children with mild-to-moderate CF lung disease. For comparison, we estimated the association between Pa status and pulmonary function tests (PFTs), chest X-rays (CXR) scores, and BMI. Pa acquisition was determined from respiratory culture results and systematic review of clinic notes.All subjects had respiratory cultures performed prior to or at baseline with a median of 19 months of retrospective culture observation (SD = 15.7 months, range: 0-52.5 months). The difference between age-adjusted mean total HRCT score for Pa+ versus Pa- was highly significant (P < 0.00001) with a near-perfect separation between scores in Pa+ versus Pa- patients. Similar results were found for several HRCT sub-scores. Among PFTs, only residual volume-to-total lung capacity (RV/TLC) had a significant difference between group means (P = 0.03), but the overlap between groups in RV/TLC measurements was large.CF HRCT scores correlate highly with Pa acquisition, a clinically meaningful measure of progressing CF lung disease. HRCT scores are highly sensitive at predicting Pa acquisition status, while most PFT measures, chest radiograph (CXR) scores, and body mass index are not. These results provide further evidence that HRCT is appropriate for use in patient care and as an outcome measure in clinical trials.

    View details for DOI 10.1002/ppul.21107

    View details for Web of Science ID 000271602200009

    View details for PubMedID 19824046

  • Discordance rates between preliminary and final radiology reports on cross-sectional imaging studies at a level 1 trauma center ACADEMIC RADIOLOGY Stevens, K. J., Griffiths, K. L., Rosenberg, J., Mahadevan, S., Zatz, L. M., Leung, A. N. 2008; 15 (10): 1217-1226


    The goal was to determine discordance rates between preliminary radiology reports provided by on-call radiology house staff and final reports from attending radiologists on cross-sectional imaging studies requested by emergency department staff after hours.A triplicate carbon copy reporting form was developed to provide permanent records of preliminary radiology reports and to facilitate communication of discrepant results to the emergency department. Data were collected over 21 weeks to determine the number of discordant readings. Patients' medical records were reviewed to show whether discrepancies were significant or insignificant and to assess their impact on subsequent management and patient outcome.The emergency department requested 2830 cross-sectional imaging studies after hours and 2311 (82%) had a copy of the triplicate form stored in radiology archives. Discrepancies between the preliminary and final report were recorded in 47 (2.0%), with 37 (1.6%) considered significant: 14 patients needed no change, 13 needed a minor change, and 10 needed a major change in subsequent management. Ten (0.43%) of the discordant scans were considered insignificant. A random sample of 104 (20%) of the 519 scans without a paper triplicate form was examined. Seventy-one (68%) did have a scanned copy of the triplicate form in the electronic record, with a discrepancy recorded in 3 (4.2%), which was not statistically different from the main cohort (P = .18).Our study suggests a high level of concordance between preliminary reports from on-call radiology house staff and final reports by attending subspecialty radiologists on cross-sectional imaging studies requested by the emergency department.

    View details for DOI 10.1016/j.acra.2008.03.017

    View details for PubMedID 18790392

  • Primary interpretation of thoracic MDCT images using coronal reformations AMERICAN JOURNAL OF ROENTGENOLOGY Kwan, S. W., Partik, B. L., Zinck, S. E., Chan, F. P., Kee, S. T., Leung, A. N., Voracek, M., Rubin, G. D. 2005; 185 (6): 1500-1508


    The objective of this study was to evaluate the accuracy and efficiency of primary interpretation of thoracic MDCT using coronal reformations as compared with transverse images.Fifty patients (18 females, 32 males; age range, 15-93 years; mean age, 63.6 years) underwent 4-MDCT of the chest (detector width, 1 mm; beam pitch, 1.5). Contrast material was administered in 20 of the 50 patients. Coronal and transverse sections were reformatted into 5-mm-thick sections at 3.5-mm intervals. All available image and clinical data consensually reviewed by two thoracic radiologists served as the reference standard. Subsequently, three other thoracic radiologists independently evaluated reformatted coronal and transverse images at two separate review sessions. Each image set was assessed in 58 categories for abnormalities of the lungs, mediastinum, pleura, chest wall, diaphragm, abdomen, and skeleton. Interpretation times and number of images assessed were recorded. Sensitivity, specificity, and interobserver concordance were calculated. Differences in mean sensitivities and specificities were evaluated with Wilcoxon's signed rank test.The most common findings identified were pulmonary nodules (n = 73, transverse images; n = 72, coronal images) and emphysema (n = 45, transverse; n = 40, coronal). The mean detection sensitivity of all lesions was significantly (p = 0.001) lower on coronal (44% +/- 26% [SD]) than on transverse (51% +/- 22%) images, whereas the mean detection specificity was significantly (p = 0.005) higher (96% +/- 5% vs 95% +/- 6%, respectively). Reporting findings for significantly (p < 0.001) fewer coronal images (mean, 63.0 +/- 4.6 images) than transverse images (mean, 91.9 +/- 8.8 images) took significantly (p = 0.025) longer (mean, 263 +/- 56 sec vs 238 +/- 45 sec, respectively).Primary interpretation of thoracic MDCT is less sensitive and more time-consuming using 5-mm-thick coronal reformations as compared with transverse images.

    View details for DOI 10.2214/AJR.04.1335

    View details for Web of Science ID 000233510600019

    View details for PubMedID 16304004

  • Recurrent lymphoma of the lung - Computed tomography appearance JOURNAL OF COMPUTER ASSISTED TOMOGRAPHY Hwang, G. L., Leung, A. N., Zinck, S. E., Berry, G. J. 2005; 29 (2): 228-230


    To describe the computed tomography findings of recurrent lymphoma involving the lung.Computed tomography scans of 15 patients with biopsy-proven recurrent lymphoma involving the lung were reviewed. Group mean age of enrolled patients was 38 years (range: 14-68 years). Pathologic specimens were obtained by thoracoscopic or open wedge biopsy (n = 8), transbronchial biopsy (n = 5), and fine needle aspiration (n = 2).Nodules, the most common manifestation, were present in all patients; nodules were greater than 10 in number in 12 (80%) of 15 cases and predominantly 6-10 mm in size in 8 cases (53%). Nodular distribution was bilateral and multilobar except in 2 patients, in whom a solitary pulmonary nodule was found. Lymphadenopathy was the second most common finding; it was seen in 13 (87%) of 15 cases and involved an average of 5 nodal stations.Recurrent lymphoma in the lung most commonly manifests as multiple pulmonary nodules that are typically bilateral and multilobar in distribution.

    View details for Web of Science ID 000228030400014

    View details for PubMedID 15772542

  • Pulmonary nodules on multi-detector row CT scans: Performance comparison of radiologists and computer-aided detection RADIOLOGY Rubin, G. D., Lyo, J. K., Paik, D. S., Sherbondy, A. J., Chow, L. C., Leung, A. N., Mindelzun, R., Schraedley-Desmond, P. K., Zinck, S. E., Naidich, D. P., Napel, S. 2005; 234 (1): 274-283


    To compare the performance of radiologists and of a computer-aided detection (CAD) algorithm for pulmonary nodule detection on thin-section thoracic computed tomographic (CT) scans.The study was approved by the institutional review board. The requirement of informed consent was waived. Twenty outpatients (age range, 15-91 years; mean, 64 years) were examined with chest CT (multi-detector row scanner, four detector rows, 1.25-mm section thickness, and 0.6-mm interval) for pulmonary nodules. Three radiologists independently analyzed CT scans, recorded the locus of each nodule candidate, and assigned each a confidence score. A CAD algorithm with parameters chosen by using cross validation was applied to the 20 scans. The reference standard was established by two experienced thoracic radiologists in consensus, with blind review of all nodule candidates and free search for additional nodules at a dedicated workstation for three-dimensional image analysis. True-positive (TP) and false-positive (FP) results and confidence levels were used to generate free-response receiver operating characteristic (ROC) plots. Double-reading performance was determined on the basis of TP detections by either reader.The 20 scans showed 195 noncalcified nodules with a diameter of 3 mm or more (reference reading). Area under the alternative free-response ROC curve was 0.54, 0.48, 0.55, and 0.36 for CAD and readers 1-3, respectively. Differences between reader 3 and CAD and between readers 2 and 3 were significant (P < .05); those between CAD and readers 1 and 2 were not significant. Mean sensitivity for individual readings was 50% (range, 41%-60%); double reading resulted in increase to 63% (range, 56%-67%). With CAD used at a threshold allowing only three FP detections per CT scan, mean sensitivity was increased to 76% (range, 73%-78%). CAD complemented individual readers by detecting additional nodules more effectively than did a second reader; CAD-reader weighted kappa values were significantly lower than reader-reader weighted kappa values (Wilcoxon rank sum test, P < .05).With CAD used at a level allowing only three FP detections per CT scan, sensitivity was substantially higher than with conventional double reading.

    View details for DOI 10.1148/radiol.2341040589

    View details for Web of Science ID 000225864800038

    View details for PubMedID 15537839

  • Chronic expanding hematoma: Mystery or misnomer? Reply AMERICAN JOURNAL OF ROENTGENOLOGY Hwang, G. L., Moffat, S. D., Mitchell, J. D., Leung, A. N. 2004; 183 (1): 244-244
  • Case 63: hepatopulmonary syndrome. Radiology Leung, A. N. 2003; 229 (1): 64-67

    View details for PubMedID 14519870

  • Invasive aspergillosis in the setting of cardiac transplantation 37th Annual Meeting of the Infectious-Diseases-Society-of-America Montoya, J. G., Chaparro, S. V., Celis, D., Cortes, J. A., Leung, A. N., Robbins, R. C., Stevens, D. A. UNIV CHICAGO PRESS. 2003: S281?S292


    Among patients undergoing heart transplantation, Aspergillus is the opportunistic pathogen with the highest attributable mortality. The median time of onset from transplantation for invasive pulmonary aspergillosis (IPA) was 46 days, but the median time to first positive culture result was 104 days among patients with Aspergillus colonization but no invasive disease. Most patients with IPA presented with fever and cough within the first 90 days of transplantation and with single or multiple pulmonary nodules. None of the heart transplant recipients with either IPA or invasive extrapulmonary aspergillosis (IEPA) had associated neutropenia. Human leukocyte antigen A1 locus was found significantly more frequently among patients colonized with Aspergillus than among patients with IPA (P<.006) or IEPA (P<.001). Even in the absence of neutropenia, IPA should be suspected for heart transplant recipients who have fever and respiratory symptoms within the first 3 months of transplantation, have a positive result of culture of respiratory secretions, and have abnormal radiological findings (particularly nodules).

    View details for PubMedID 12975755

  • Composite spirometric-computed tomography outcome measure in early cystic fibrosis lung disease AMERICAN JOURNAL OF RESPIRATORY AND CRITICAL CARE MEDICINE Robinson, T. E., Leung, A. N., Northway, W. H., Blankenberg, F. G., Chan, F. P., Bloch, D. A., Holmes, T. H., Moss, R. B. 2003; 168 (5): 588-593


    With the advent of therapies aimed at young patients with cystic fibrosis, who have mildly reduced pulmonary function, the need for improved outcome measures that discriminate treatment effects has become important. Pulmonary function measurements or chest high-resolution computed tomography (HRCT) scores have been separately used to assess interventions. We evaluated these modalities separately and together during a treatment study to develop a more sensitive outcome measure. In a 1-year trial, 25 children randomized either to daily Pulmozyme or to normal saline aerosol were evaluated at randomization and at 3 and 12 months. Outcome variables were pulmonary function test (PFT) results, a global HRCT score, and a composite score incorporating PFTs and HRCT scoring. Regression analyses with generalized estimating equations permitted estimation of the difference in treatment effect between groups over time for each outcome. The largest difference in treatment effects observed at 12 months, measured by the percentage change from baseline, were with the composite total and maximal CT/PFT scores (35.4 and 30.4%), compared with mean forced expiratory flow during the middle half of the FVC (FEF25-75%) (13.0%) and total and maximal global HRCT scores (6.2%, 7.2%). The composite total and maximal CT/PFT scores were the most sensitive outcome measures for discriminating a treatment effect in children with cystic fibrosis with normal or mildly reduced pulmonary function during a 1-year trial of Pulmozyme.

    View details for DOI 10.1164/rccm.200209-1093OC

    View details for PubMedID 12746252

  • Chronic expanding hematoma of the thorax AMERICAN JOURNAL OF ROENTGENOLOGY Hwang, G. L., Moffatt, S. D., Mitchell, J. D., Leung, A. N. 2003; 180 (4): 1182-1183

    View details for Web of Science ID 000181745500064

    View details for PubMedID 12646486

  • Videofluoroscopy of swallowing abnormalities in 22 symptomatic patients after cardiovascular surgery. AMERICAN JOURNAL OF ROENTGENOLOGY Partik, B. L., Scharitzer, M., Schueller, G., Voracek, M., Schima, W., Schober, E., Mueller, M. R., Leung, A. N., Denk, D. M., Pokieser, P. 2003; 180 (4): 987-992


    The aim of this study was to evaluate the types of swallowing abnormalities that occur in symptomatic patients who have undergone cardiovascular surgery.From 1994 to 2001, 22 patients (17 males and five females; age range, 4-89 years; mean age, 64 years) who had swallowing abnormalities after cardiovascular surgery were referred for a videofluoroscopic swallowing study. Each study was analyzed for functional abnormalities of the tongue, soft palate, epiglottis, hyoid and larynx, pharynx, upper esophageal sphincter, and esophagus. Also, the performance of transesophageal echocardiography, long-term intubation, or both was noted.Swallowing abnormalities were present in 18 patients (81.8%) (range, one to eight functional abnormalities; mean, 3.9 functional abnormalities). The distribution of abnormalities across the functional units statistically significantly deviated (chi(2) = 14.4; df = 6; p = 0.025) from uniform distribution, with abnormalities most commonly involving the hyoid and larynx (13 patients [59.1%]) and the pharynx (10 patients [45.5%]). Aspiration was found in 13 patients (59.1%) (predeglutitive, n = 1; intradeglutitive, n = 4; postdeglutitive, n = 3; and mixed, n = 5). In the 14 patients (63.6%) who underwent transesophageal echocardiography, long-term intubation, or both, we frequently found incomplete tilting of the epiglottis, pharyngeal weakness, and postdeglutitive aspiration.Most patients with swallowing problems after cardiovascular surgery present with multiple abnormalities that most commonly affect the hyoid and larynx and the pharynx and result predominantly in intra- or postdeglutitive aspiration. The performance of transesophageal echocardiography and long-term intubation may influence the types of swallowing abnormalities.

    View details for Web of Science ID 000181745500018

    View details for PubMedID 12646442

  • Using a dedicated lung-marker system for localization of pulmonary nodules before thoracoscopic surgery AMERICAN JOURNAL OF ROENTGENOLOGY Partik, B. L., Leung, A. N., Muller, M. R., Breitenseher, M., Eckersberger, F., Dekan, G., Helbich, T. H., Metz, V. 2003; 180 (3): 805-809


    Our aim was to evaluate the effectiveness of a commercially available dedicated lung-marker system for localization of pulmonary nodules before video-assisted thoracoscopic surgery.Guidewires were positioned under CT fluoroscopy guidance in 16 patients (11 men, five women; age range, 39-79 years; mean age, 60.4 years). We measured the size of the targeted nodule, its distance to the closest pleural surface, the angle between the introducer needle and the chest wall, and the time for performance of the procedure in each patient. Note was made of any complications after guidewire placement.In the 16 patients, the average nodule size was 6.7 mm (range, 3-12 mm), the average distance to the pleural surface was 10.6 mm (range, 3-22 mm), and the average pleural puncture angle was 59 degrees (range, 25-78 degrees). The marking procedure was completed within an average of 9.5 min (range, 7-15 min). Small pneumothoraces occurred in five (31.3%) of 16 patients. In 15 (93.8%) of 16 patients, thoracoscopic resection of the targeted nodule was successful; in one patient with dyspnea (6.3%), inaccurate localization resulting in an open thoracotomy occurred because an intervening fissure was not visualized. Dislodgement of the guidewire into the pleural space occurred in one patient (6.3%).The dedicated lung-marker system is a fast and effective method for localization of pulmonary nodules before thoracoscopic resection.

    View details for Web of Science ID 000181153400042

    View details for PubMedID 12591700

  • Fast tomosynthesis for lung cancer detection using the SBDX geometry Medical Imaging 2003 Conference Fahrig, R., Pineda, A. R., Solomon, E. G., Leung, A. N., Pejc, N. J. SPIE-INT SOC OPTICAL ENGINEERING. 2003: 371?378
  • Bronchogenic carcinoma after lung transplantation: Frequency, clinical characteristics, and imaging findings RADIOLOGY Collins, J., Kazerooni, E. A., Lacomis, J., McAdams, H. P., Leung, A. N., Shiau, M., Semenkovich, J., Love, R. B. 2002; 224 (1): 131-138


    To determine the frequency, clinical characteristics, and radiologic findings of bronchogenic carcinoma in patients surviving more than 1 month after lung transplantation.The study population was composed of 2,168 consecutive patients at seven lung transplantation centers who survived longer than 1 month after lung transplantation. Medical records, chest radiographs, and computed tomographic (CT) scans obtained at the time of diagnosis and prior images when available were reviewed for various items of information and imaging features.Twenty-four (1%) of the 2,168 patients, all with single-lung transplants, developed cancer in the native lung. Eighteen patients had emphysema, and six had pulmonary fibrosis. The frequencies of cancer in patients with emphysema and fibrosis were 2% (18 of 859 patients) and 4% (six of 147 patients), respectively. Twelve (50%) of their 24 cancers were detected at chest radiography. Fourteen (58%) patients had clinical symptoms. Twenty-one (88%) of the 24 patients had one (n = 11) or more (n = 10) nodules, and nine (38%) had one (n = 8) or more (n = 1) masses visible on CT scans. Nodules and masses were visible on 12 (50%) and seven (29%) of 24 chest radiographs, respectively. Eleven (48%) of 23 cancers for which prior chest radiographs were available were seen retrospectively on prior chest radiographs.Bronchogenic carcinoma develops in the native lung of transplant recipients with emphysema and pulmonary fibrosis with frequencies of 2% and 4%, respectively. The carcinomas most commonly manifest as a pulmonary nodule or mass on chest radiographs, with more nodules seen on CT scans.

    View details for DOI 10.1148/radiol.2241011189

    View details for Web of Science ID 000176454700019

    View details for PubMedID 12091672

  • Short echo time MR spectroscopic imaging of the lung parenchyma JOURNAL OF MAGNETIC RESONANCE IMAGING Gold, G. E., Pauly, J. M., Leung, A. N., Block, W. F., Meyer, C. H., Sze, R., Macovski, A., Stark, P. 2002; 15 (6): 679-684


    To perform short echo time MR spectroscopic imaging of the lung parenchyma on normal volunteers.A short echo time projection-reconstruction spectroscopic imaging sequence was implemented on a commercial 1.5T whole body MRI scanner. Images and spectra of the lung parenchyma were obtained from five normal volunteers. Breath-held spectroscopic imaging was also performed.Spectroscopic imaging of short-T2* species allows visualization of different anatomic structures based upon their frequency shifts. A characteristic peak from the parenchyma was seen at three ppm from water frequency.Short echo time MR spectroscopic imaging of the lung parenchyma was demonstrated in normal volunteers. This method may improve proton imaging of the lungs and add specificity to the diagnosis of pulmonary disease.

    View details for DOI 10.1002/jmri.10113

    View details for Web of Science ID 000175918300008

    View details for PubMedID 12112518

  • Pulmonary cryptococcosis: CT and pathologic findings JOURNAL OF COMPUTER ASSISTED TOMOGRAPHY Zinck, S. E., Leung, A. N., Frost, M., Berry, G. J., Muller, N. L. 2002; 26 (3): 330-334


    The purpose of this work was to describe the CT and pathologic findings of pulmonary cryptococcosis.CT scans of 11 patients (7 immunocompromised, 4 immunocompetent) with proven pulmonary cryptococcosis were analyzed for number, morphologic characteristics, and distribution of parenchymal abnormalities as well for presence of lymphadenopathy and pleural effusion. Pathology of lung specimens obtained by open biopsy or resection (n = 5) and transbronchial biopsy (n = 1) was reviewed by one dedicated pulmonary pathologist.Pulmonary nodules, either solitary or multiple, were the most common CT finding, present in 10 of 11 patients (91%); associated findings included masses (n = 4), CT halo sign (n = 3), and consolidation (n = 2). On histologic examination, focal areas of ground-glass attenuation surrounding or adjacent to nodules were found to represent airspace collections of macrophages and proteinaceous fluid.Pulmonary cryptococcosis should be considered in the differential diagnosis of solitary or multiple pulmonary nodules (with or without associated CT halo sign), particularly in immunocompromised patients.

    View details for DOI 10.1097/01.RCT.0000014445.78.502.F9

    View details for Web of Science ID 000175799800002

    View details for PubMedID 12016357

  • CT of noninfectious granulomatous lung disease RADIOLOGIC CLINICS OF NORTH AMERICA Zinck, S. E., Schwartz, E., Berry, G. J., Leung, A. N. 2001; 39 (6): 1189-?


    Noninfectious granulomatous diseases of the lung consist of a diverse group of disorders that logically can be subdivided into those with and without associated vasculitis. This article reviews the epidemiologic, clinical, pathologic, and radiologic features of sarcoidosis, hypersensitivity pneumonitis, berylliosis, and the five entities traditionally classified as pulmonary angiitis and granulomatosis.

    View details for Web of Science ID 000172023200008

    View details for PubMedID 11699668

  • Cellulose granulomatosis presenting as centrilobular nodules: CT and histologic findings AMERICAN JOURNAL OF ROENTGENOLOGY Bendeck, S. E., Leung, A. N., Berry, G. J., Daniel, D., Ruoss, S. J. 2001; 177 (5): 1151-1153

    View details for Web of Science ID 000171732700034

    View details for PubMedID 11641191

  • Spirometer-triggered high-resolution computed tomography and pulmonary function measurements during an acute exacerbation in patients with cystic fibrosis JOURNAL OF PEDIATRICS Robinson, T. E., Leung, A. N., Northway, W. H., Blankenberg, F. G., Bloch, D. A., Oehlert, J. W., Al-Dabbagh, H., Hubli, S., Moss, R. B. 2001; 138 (4): 553-559


    To evaluate a high-resolution computed tomography (HRCT) scoring system, clinical parameters, and pulmonary function measurements in patients with cystic fibrosis (CF) before and after therapy for a pulmonary exacerbation.Patients (n = 17) were evaluated by spirometer-triggered HRCT imaging, clinical parameters, and pulmonary function tests (PFTs) before and after treatment. HRCT scans were reviewed by 3 radiologists using a modified Bhalla scoring system.Bronchiectasis, bronchial wall thickening, and air trapping were identified in all subjects on initial evaluation. The initial total HRCT score correlated significantly with the Brasfield score (r = -.91, P <.001) and several PFT measures. After treatment, there were improvements in the acute change clinical score (ACCS) (P <.001), most pulmonary function measurements, and total HRCT score (P <.05). Bronchiectasis, bronchial wall thickening, and air trapping did not significantly change. Mucus plugging subcomponent HRCT score, slow vital capacity (SVC), forced expiratory volume in 1 second (FEV(1)), and forced vital capacity (FVC) (percent predicted) and reversible and total HRCT scores were most sensitive to change by effect size analysis.Improvements occurred with treatment in total and reversible HRCT scores, PFTs, and ACCS. Total and reversible HRCT scores and percent predicted SVC, FEV1, and FVC were the most sensitive to change. The greatest change was seen in the mucus plugging subcomponent HRCT score.

    View details for PubMedID 11295720

  • Case report - Paclitaxel-induced hypersensitivity pneumonitis: Radiographic and CT findings AMERICAN JOURNAL OF ROENTGENOLOGY Wong, P., Leung, A. N., Berry, G. J., Atkins, K. A., Montoya, J. G., Ruoss, S. J., Stockdale, F. E. 2001; 176 (3): 718-720
  • Paclitaxel-induced hypersensitivity pneumonitis: radiographic and CT findings. AJR. American journal of roentgenology Wong, P., Leung, A. N., Berry, G. J., Atkins, K. A., Montoya, J. G., Ruoss, S. J., Stockdale, F. E. 2001; 176 (3): 718-720

    View details for PubMedID 11222212

  • Digital storage phosphor chest radiography: An ROC study of the effect of 2K versus 4K matrix size on observer performance RADIOLOGY Miro, S. P., Leung, A. N., Rubin, G. D., Choi, Y. H., Kee, S. T., Mindelzun, R. E., Stark, P., Wexler, L., Plevritis, S. K., Betts, B. J. 2001; 218 (2): 527-532


    To compare observer performance in the detection of abnormalities on 1,760 x 2,140 matrix (2K) and 3,520 x 4,280 matrix (4K) digital storage phosphor chest radiographs.One hundred sixty patients who underwent dedicated computed tomography (CT) of the thorax were prospectively recruited into the study. Posteroanterior and lateral computed radiographs of the chest were acquired in each patient and printed in 2K and 4K formats. Six radiologists independently analyzed the hard-copy images and scored the presence of parenchymal (opacities 2 cm, and subtle interstitial), mediastinal, and pleural abnormalities on a five-point confidence scale. With CT as the reference standard, observer performance tests were carried out by using receiver operating characteristic (ROC) analysis.Analysis of averaged observer performance showed 2K and 4K images were equally effective in detection of all three groups of abnormalities. In the detection of the three subtypes of parenchymal abnormalities, there were no significant differences in averaged performance between the 2K and 4K formats (area below ROC curve [A(z)] values: opacities 2 cm, 0.86 +/-.025 and 0.85 +/- 0.030; subtle interstitial abnormalities, 0.73 +/- 0.041 and 0.72 +/- 0.041). Averaged performance in detection of mediastinal and pleural abnormalities was equivalent (A(z) values: mediastinal, 0.70 +/- 0.046 and 0.73 +/- 0.033; pleural, 0.85 +/- 0.032 and 0.86 +/- 0.033).Observer performance in detection of parenchymal, mediastinal, and pleural abnormalities was not significantly different on 2K and 4K storage phosphor chest radiographs.

    View details for Web of Science ID 000166728200033

    View details for PubMedID 11161174

  • A model for faculty mentoring in academic radiology ACADEMIC RADIOLOGY Illes, J., Glover, G. H., Wexler, L., Leung, A. N., Glazer, G. M. 2000; 7 (9): 717-724


    The purpose of this report is to describe the development and implementation of a faculty mentoring program in radiology designed to promote the career development of junior faculty and enhance communication in the department.The mentoring program was implemented in five stages: organizational readiness, participant recruitment, mentor matching and orientation, implementation, and evaluation. Evaluations were based on Likert scale ratings and qualitative feedback. A retrospective analysis was also conducted of the annual performance reviews of junior faculty in the areas of research, teaching, patient care, and overall performance.An average of 83% (19 of 23) of the junior faculty participated in the pilot phase of the mentoring program. During five rounds of testing, the median rating (1 indicates not important; 10, extremely important) from responding junior faculty was 10 for overall value of individual mentoring meetings; the median rating for the mentors responding was 8.75. Research and academic development were identified as the areas of greatest importance to the faculty. Research and patient care were most improved as assessed by faculty peers during performance reviews. The schedule of semiannual formal mentoring meetings was reported to be optimal.The program was implemented to the satisfaction of junior faculty and mentors, and longitudinal performance suggests positive effects. Issues to be contended with include confidentiality and the time needed for mentoring beyond already saturated schedules. Overall, the authors propose that mentoring programs can be an asset to academic radiology departments and a key factor in maintaining their vitality.

    View details for Web of Science ID 000089143200007

    View details for PubMedID 10987334

  • A curriculum in chest radiology for diagnostic radiology residency, with goals and objectives ACADEMIC RADIOLOGY Kazerooni, E. A., Collins, J., Reddy, G. P., Nath, H. P., Batra, P. V., Boxt, L. M., Duerinckx, A. J., Erasmus, J. J., Fishman, J. E., Leung, A. N., Tarver, R. D., Wexler, L., Winer-Muram, H. T. 2000; 7 (9): 730-743

    View details for Web of Science ID 000089143200010

    View details for PubMedID 10987336

  • Aorta and iliac arteries: Single versus multiple detector-row helical CT angiography RADIOLOGY Rubin, G. D., Shiau, M. C., Leung, A. N., Kee, S. T., Logan, L. J., Sofilos, M. C. 2000; 215 (3): 670-676


    To compare single- versus four-channel helical computed tomographic (CT) aortography.Forty-eight patients with aortic aneurysm or dissection underwent four- and one-channel CT angiography. Scan pairs covered the thoracic inlet to the diaphragm (n = 10) and supraceliac abdominal aorta (n = 19) or thoracic inlet (n = 19) to the femoral arterial bifurcations. For four-channel CT, nominal section thickness and pitch were 2.5 mm and 6.0, respectively, and for one-channel CT, 3.0 mm and 2.0 to the infrarenal aorta and 5.0 mm and 2.0 to the femoral arteries. Effective section thickness, scanning duration, scanning coverage, dose of iodinated contrast material, and mean aortoiliac attenuation were compared. Data were summarized as speed (coverage/duration), scanning efficiency (speed/section thickness), and contrast efficiency (mean aortic attenuation/dose of contrast material).At four- versus one-channel CT, CT angiography was 2.6 times faster, scanning efficiency was 4.1 times greater, contrast efficiency was 2.5 times greater, dose of contrast material was reduced (mean, 57%; 97 vs 232 mL) without a significant change in aortic enhancement, and sections were thinner (mean, 40%; 3.2 vs 5.3 mm) despite a 59% shorter scanning duration (22 vs 56 seconds).Substantially reduced doses of contrast medium, shorter scanning durations, and narrower effective sections result with four- versus one-channel CT aortography. No advantages of one-channel CT aortography were demonstrated.

    View details for Web of Science ID 000087247000009

    View details for PubMedID 10831682

  • Bronchocentric granulomatosis: Computed tomographic findings in five patients CLINICAL RADIOLOGY Ward, S., Heyneman, L. E., Flint, J. D., Leung, A. N., Kazerooni, E. A., Muller, N. L. 2000; 55 (4): 296-300


    The aim of this study was to assess the CT manifestations of bronchocentric granulomatosis.The CT results of five patients with bronchocentric granulomatosis were retrospectively analysed. The patients ranged from 20 to 72 years of age and included three men and two women. The diagnosis of bronchocentric granulomatosis was made at lobectomy (n = 2), open lung biopsy (n = 2), and transbronchial biopsy (n = 1). Only one of the five patients had asthma.The main findings consisted of a spiculated mass lesion (n = 3) or lobar consolidation with associated mild volume loss (n = 2). One of the two patients with consolidation had extensive mucoid impaction. The abnormalities involved predominantly an upper lobe in four patients and a lower lobe in one patient. In the four resected specimens, the macroscopic pathological appearance was consolidation (n = 2) and mass lesion (n = 2). Microscopically, the typical histology of airway-centred necrotizing granulomata was present in all cases. Aspergillus hyphae were identified in two cases. Nocardia sp. was cultured from the biopsy specimen in one case.The CT manifestations of bronchocentric granulomatosis consist of a focal mass or lobar consolidation with atelectasis. These reflect the presence of granuloma formation with or without associated bronchial obstruction.

    View details for Web of Science ID 000089135100008

    View details for PubMedID 10767190

  • Primary bronchogenic carcinoma after heart or lung transplantation: Radiologic and clinical findings JOURNAL OF THORACIC IMAGING Choi, Y. H., Leung, A. N., Miro, S., Poirier, C., Hunt, S., Theodore, J. 2000; 15 (1): 36-40


    Chronic immunosuppression in organ transplant recipients predisposes to the development of malignant disease. The authors describe their 29-year institutional experience of bronchogenic carcinoma developing after heart and lung transplantation. Seven cases of bronchogenic carcinoma were diagnosed in 1,119 heart and lung transplant recipients. Computed tomography scans and radiographs at time of diagnosis, as well as prior radiographs available in six patients were retrospectively analyzed by two radiologists in consensus. The seven cases involved six heart and one lung transplant recipients. Six patients were smokers with a mean smoking history of 66 pack-years. Mean time interval from transplantation to cancer detection was 25 months. Radiologic findings consisted of a solitary pulmonary nodule (n = 3), mass with satellite nodules (n = 1), and obstructive pneumonitis (n = 1). In the sixth patient, the cancer was not radiographically visible because of obscuration by adjacent fibrosis. On review, radiographic abnormalities were present a mean of 12 months prior to diagnosis in 66% of patients. In the heart or lung transplant population, bronchogenic carcinoma develops in recipients with extensive smoking histories. It presents radiographically as a nodule, mass, or obstructive pneumonitis, and is usually visible on radiographs before the time of diagnosis.

    View details for Web of Science ID 000084709000008

    View details for PubMedID 10634661

  • Computed tomographic angiography: Historical perspective and new state-of-the-art using multi detector-row helical computed tomography Workshop on Multiple Perspectives in Magnetic Resonance Imaging Contrast Rubin, G. D., Shiau, M. C., Schmidt, A. J., Fleischmann, D., Logan, L., Leung, A. N., Jeffrey, R. B., Napel, S. LIPPINCOTT WILLIAMS & WILKINS. 1999: S83?S90


    Since its clinical introduction in 1991, volumetric computed tomography scanning using spiral or helical scanners has resulted in a revolution for diagnostic imaging. In addition to new applications for computed tomography, such as computed tomographic angiography and the assessment of patients with renal colic, many routine applications such as the detection of lung and liver lesions have substantially improved. Helical computed tomographic technology has improved over the past eight years with faster gantry rotation, more powerful X-ray tubes, and improved interpolation algorithms, but the greatest advance has been the recent introduction of multi detector-row computed tomography scanners. These scanners provide similar scan quality at a speed gain of 3-6 times greater than single detector-row computed tomography scanners. This has a profound impact on the performance of computed tomography angiography, resulting in greater anatomic coverage, lower iodinated contrast doses, and higher spatial resolution scans than single detector-row systems.

    View details for Web of Science ID 000084391500012

    View details for PubMedID 10608402

  • Accuracy of CT in the diagnosis of allergic bronchopulmonary aspergillosis in asthmatic patients AMERICAN JOURNAL OF ROENTGENOLOGY Ward, S., Heyneman, L., Lee, M. J., Leung, A. N., Hansell, D. M., Muller, N. L. 1999; 173 (4): 937-942


    The purpose of this study was to assess the accuracy of high-resolution CT in the diagnosis of allergic bronchopulmonary aspergillosis in asthmatic patients.The high-resolution CT scans of 44 asthmatic patients with allergic bronchopulmonary aspergillosis and 38 asthmatic patients without allergic bronchopulmonary aspergillosis were analyzed retrospectively and randomly by two independent observers for these features: bronchial wall thickening, bronchiectasis, centrilobular nodules, mucoid impaction, mosaic perfusion, atelectasis, and consolidation. Each observer made a final diagnosis with a stated degree of confidence. The results are expressed as the average number of observations by the two observers.Findings seen more commonly in patients with allergic bronchopulmonary aspergillosis than in patients with asthma alone included bronchiectasis, centrilobular nodules, and mucoid impaction (p < .01, chi-square test). Bronchiectasis was present in 42 (95%) of 44 patients with allergic bronchopulmonary aspergillosis, centrilobular nodules in 41 (93%), and mucoid impaction in 29.5 (67%) (average of two observers). In the asthmatic control group, bronchiectasis was detected in 11 (29%) of 38 patients, centrilobular nodules in 10.5 (28%), and mucoid impaction in 4%. Bronchiectasis was seen in 184 (70%) of 264 lobes of patients with allergic bronchopulmonary aspergillosis compared with 19.5 (9%) of 228 lobes in asthmatic controls (p < .001, chi-square test).In asthmatic patients, bronchiectasis affecting three or more lobes, centrilobular nodules, and mucoid impaction are findings on high-resolution CT that are highly suggestive of allergic bronchopulmonary aspergillosis.

    View details for Web of Science ID 000082714900015

    View details for PubMedID 10511153

  • Radiology of pneumonia CLINICS IN CHEST MEDICINE Katz, D. S., Leung, A. N. 1999; 20 (3): 549-?


    Chest radiography is the imaging technique of choice in evaluating patients with suspected pneumonia because of its low radiation dose, low cost, and wide accessibility. In daily practice, radiographs are used to confirm the clinical diagnosis of pneumonia, characterize the extent and severity of disease, search for complications such as empyema, monitor the response to therapy, and examine for possible alternative or additional diagnoses. Although CT scan has no defined role in the routine assessment of patients with either community-acquired or nosocomial pneumonias, its advantages of superior contrast resolution and cross-sectional display can often be helpful in the analysis of complex cases, particularly when radiographic evidence of associated central obstruction, cavitation, lymphadenopathy, or empyema is equivocal. In the immunocompromised patient population, high-resolution CT has been shown to be more sensitive than plain film radiography in the early detection of pulmonary infections.

    View details for Web of Science ID 000083128300008

    View details for PubMedID 10516903

  • Radiologic findings: Pulmonary infections after bone marrow transplantation JOURNAL OF THORACIC IMAGING Choi, Y. H., Leung, A. N. 1999; 14 (3): 201-206


    Pulmonary infections are a significant source of morbidity and mortality in the bone marrow transplant population. This pictorial essay reviews the typical time period and imaging findings associated with common pulmonary pathogens that affect bone marrow transplant recipients.

    View details for Web of Science ID 000081198700007

    View details for PubMedID 10404506

  • Standardized high-resolution CT of the lung using a spirometer-triggered electron beam CT scanner AMERICAN JOURNAL OF ROENTGENOLOGY Robinson, T. E., Leung, A. N., Moss, R. B., Blankenberg, F. G., Al-Dabbagh, H., Northway, W. H. 1999; 172 (6): 1636-1638

    View details for Web of Science ID 000080427900034

    View details for PubMedID 10350305

  • Assessment of pulmonary lesions with F-18-fluorodeoxyglucose positron imaging using coincidence mode gamma cameras JOURNAL OF NUCLEAR MEDICINE Weber, W., Young, C., Abdel-Dayem, H. M., Sfakianakis, G., Weir, G. J., Swaney, C. M., Gates, M., Stokkel, M. P., Parker, A., Hines, H., Khanvali, B., Liebig, J. R., Leung, A. N., Sollitto, R., Caputo, G., WAGNER, H. N. 1999; 40 (4): 574-578


    Accurate assessment of lung carcinoma remains a significant clinical problem, often leading to surgical procedures without curative potential. PET with 18F-fluorodeoxyglucose (FDG) has shown promise in differentiating benign from malignant lesions and in staging the extent of disease, resulting in improved treatment at a significant cost savings. This multicenter prospective study used dual-detector coincidence imaging with FDG to categorize pulmonary lesions as benign or malignant. The goal of this study was to determine the sensitivity and specificity of dual-detector coincidence imaging of FDG in patients with pulmonary lesions who were scheduled to have a diagnostic procedure for histopathologic confirmation.A total of 96 patients with pulmonary lesions with a lesion size ranging from 1 to 7 cm with a mean of 3.44 cm based on their chest radiograph or CT scan were studied using FDG scans with a dual-detector coincidence detection system. An additional 24 patients were entered as control subjects. The studies of 120 subjects were interpreted in random order by three physicians experienced in the use of FDG in patients with lung cancer. Surgical pathology was used as the standard for identifying malignant lesions.There was 94% agreement between the readers in the independent interpretation of the FDG studies. In the 96 patients with pulmonary lesions, FDG studies were 97% sensitive and 80% specific in identifying proven malignant lesions.The results of this prospective study provide evidence that dual-detector coincidence imaging with FDG provides an accurate, sensitive and specific means of diagnosing malignancy in patients with pulmonary lesions.

    View details for Web of Science ID 000079521800016

    View details for PubMedID 10210215

  • Spirometer-triggered high resolution computed tomography (HRCT) of the chest, clinical score, and pulmonary function measurements in cystic fibrosis (CF) patients before and after treatment for a pulmonary exacerbation Robinson, T. E., Leung, A. N., Moss, R. B., Blankenberg, F. G., Bloch, D. A., Oehlert, J. W., Al-Dabbagh, H., Hubli, S., Northway, W. H. INT PEDIATRIC RESEARCH FOUNDATION, INC. 1999: 355A
  • Pulmonary infections after bone marrow transplantation: Clinical and radiographic findings RADIOLOGY Leung, A. N., Gosselin, M. V., Napper, C. H., Braun, S. G., Hu, W. W., Wong, R. M., Gasman, J. 1999; 210 (3): 699-710


    To assess the clinical and radiographic findings of pulmonary infections diagnosed by using invasive means.Fifty-nine episodes of pulmonary infection were diagnosed in 52 (7.2%) of a consecutive series of 725 adult bone marrow transplant recipients. Causative organisms, time of diagnoses, radiographic patterns, and mortality rates were reviewed.Cytomegalovirus and Aspergillus species were the two most common pathogens, accounting for 22 and 17 episodes, respectively. During the first 30 days after bone marrow transplantation, fungi caused the majority (nine [82%] of 11 episodes) of pulmonary infections; from days 31 to 100, viruses predominated (21 [62%] of 34 episodes). Recipients of allogeneic transplants had a higher probability of developing Cytomegalovirus pneumonitis than did the recipients of autologous and syngeneic transplants (P < .001). Radiographic findings of Cytomegalovirus pneumonia consisted of parenchymal opacification (90%) and innumerable nodules smaller than 5 mm (29%); in two patients, radiographs were normal. Nodules, masses, or nodules and masses, present in nine (69%) of the 13 patients with Aspergillus infection, were the most common radiographic findings in invasive aspergillosis. Bone marrow transplant recipients with a documented pulmonary infection were found to have a lower event-free survival than recipients without infection (P < .001).Opportunistic pathogens account for the majority of pulmonary infections requiring invasive diagnosis and tend to manifest at predictable times in the course of events following recovery from bone marrow transplantation. Cytomegalovirus, the most common pathogen, causes a spectrum of radiographic findings that includes normal findings. Occurrence of a pulmonary infection is associated with an increased mortality rate.

    View details for Web of Science ID 000078796500018

    View details for PubMedID 10207470

  • Pulmonary tuberculosis: The essentials RADIOLOGY Leung, A. N. 1999; 210 (2): 307-322

    View details for Web of Science ID 000078277900003

    View details for PubMedID 10207408

  • Lung transplantation for lymphangioleiomyomatosis: Role of imaging in the assessment of complications related to the underlying disease RADIOLOGY Collins, J., Muller, N. L., Kazerooni, E. A., McAdams, H. P., Leung, A. N., Love, R. B. 1999; 210 (2): 325-332


    To identify the complications and imaging findings related to lymphangioleiomyomatosis (LAM) after lung transplantation.The authors retrospectively reviewed the clinical histories and imaging studies of 13 patients from five major medical centers who underwent unilateral (n = 8) or bilateral (n = 5) lung transplantation for LAM between 1991 and 1997. Complications related to LAM, both before and after transplantation, were recorded.The following LAM-related complications were found during and after transplantation: excessive pleural adhesions (n = 4), native lung pneumothorax (n = 3), chylous effusion (n = 1), chylous ascites (n = 3), complications from renal angiomyolipomas (n = 4), and recurrent LAM (n = 1). Diagnosis could be made or suggested with computed tomography (CT) in all cases. Four patients (31%) died; one patient died of complications of LAM.Patients who have undergone lung transplantation for LAM have increased morbidity and mortality due to complications related to their underlying disease. These LAM-related complications can be diagnosed or suggested with CT.

    View details for Web of Science ID 000078277900005

    View details for PubMedID 10207410

  • Chronic pulmonary coccidioidomycosis: computed tomographic and pathologic findings in 18 patients CANADIAN ASSOCIATION OF RADIOLOGISTS JOURNAL-JOURNAL DE L ASSOCIATION CANADIENNE DES RADIOLOGISTES Kim, K. I., Leung, A. N., Flint, J. D., Muller, N. L. 1998; 49 (6): 401-407


    To review the computed tomographic (CT) findings in pathologically proven chronic pulmonary coccidioidomycosis.The study included 19 pulmonary lesions caused by mycologically and pathologically proven chronic coccidioidomycosis in 18 immunocompetent patients (aged 22 to 75 years, mean 57 years) who had a chest CT scan. Thirteen patients were Canadians who had travelled to an endemic area, and 5 were inhabitants of an endemic area in southern California and Arizona. The CT findings were assessed to determine the type, size, margin, internal architecture and location of parenchymal abnormalities.The CT findings included solitary nodules of 1.0 to 2.0 cm (mean 1.7 cm) in diameter in 17 patients, a focal area of ground-glass attenuation in 1 patient, and focal consolidation in 1 patient. Ten of the nodules had homogeneous attenuation on CT, 2 had central areas of low attenuation, 2 showed cavitation, 2 had foci of calcifications and 1 had bubble lucency. The nodules were located peripherally (in 14 patients) and centrally (in 3 patients). The predominant histologic finding in these nodules was a necrotizing granuloma. Three nodules were surrounded by halos of ground-glass attenuation, which were shown on histologic examination to represent granulomatous inflammation (in 2 cases) and pulmonary hemorrhage due to a pulmonary artery-bronchial fistula (in 1 case). Two nodules had adjacent consolidation, which was due to granulomatous inflammation surrounding a necrotizing granuloma.Necrotizing granulomas in chronic coccidioidomycosis appear as a well-defined nodule on CT, while granulomatous inflammation may appear as areas of ground-glass attenuation or consolidation.

    View details for Web of Science ID 000077752200007

    View details for PubMedID 9879269

  • Thoracic spiral CT: Influence of subsecond gantry rotation on image quality RADIOLOGY Rubin, G. D., Leung, A. N., Robertson, V. J., Stark, P. 1998; 208 (3): 771-776


    To determine if the lower milliampere second setting and shorter acquisition time of subsecond spiral computed tomography (CT) affects the image quality of thoracic CT scans.In 92 consecutive outpatients referred for thoracic CT, spiral CT (120 kV, 292 mA) was performed with 1-second (n = 45) or 0.75-second (n = 47) scanning time. An equal percentage of patients (70%) in each group received intravenous contrast medium. At six mediastinal and six lung zones, degradation due to motion and noise, respectively, were graded independently on a four-point scale by three blinded radiologists. Statistically significant differences were determine with a two-tailed test.Mediastinal image quality was significantly better on 0.75-second scans than on 1-seconds scans (P < .001). Regions with the greatest improvement in image quality were around the aortic root, cardiac ventricles, and aortic arch. Lung image quality was also better on 0.75-second scans than on 1-second scans (P = .04). On 0.75- and 1-second scans, respectively, motion-related artifacts were found to degrade image quality 6.2 and 8.7 times more than noise-related artifacts in the mediastinum and 2.6 and 3.9 times more in the lungs.Subsecond spiral CT is associated with improved clarity and diminished motion artifacts on mediastinal and pulmonary images when compared with 1-second spiral CT.

    View details for Web of Science ID 000075488200033

    View details for PubMedID 9722858

  • Epstein-Barr-virus-associated lymphoproliferative disease of the lung: CT and histologic findings 83rd Annual Meeting of the Radiological-Society-of-North-America Collins, J., Muller, N. L., Leung, A. N., McGuinness, G., Mergo, P. J., Flint, J. D., Warner, T. F., Poirier, C., Theodore, J., Zander, D., Yee, H. T. RADIOLOGICAL SOC NORTH AMERICA. 1998: 749?59


    To assess the computed tomographic (CT) and histologic findings of intrathoracic lymphoproliferative disease (LPD) associated with the Epstein-Barr virus (EBV).The authors retrospectively reviewed the CT scans of the chest and the pathologic specimens obtained in 24 patients with histologically proved intrathoracic LPD and with positive serologic findings or immunohistochemical staining for EBV. Five patients had acquired immunodeficiency syndrome (AIDS); one had common variable immune deficiency; and 18 were receiving immunosuppressive therapy for heart, lung, or heart-lung (n =15) or bone marrow (n = 2) transplantation and vasculitis (n = 1).Final diagnoses included malignant lymphoma (n = 15), polyclonal LPD (n = 8), and hyperplasia of bronchus-associated lymphoid tissue (n = 1). CT findings included multiple nodules (n = 21), lymphadenopathy (n = 9), areas of groundglass opacification (n = 8), septal thickening (n = 7), consolidation (n = 5), pleural effusion (n = 4), and solitary endobronchial lesion (n = 2). The nodules were 2-4 cm in diameter, involved mainly the middle and lower lung zones, and frequently had a predominantly peribronchovascular (n = 15) or subpleural (n = 14) distribution.EBV-associated LPD may range from benign lymphoid hyperplasia to high-grade lymphoma. The most common CT manifestation consists of multiple nodules, frequently in a predominantly peribronchovascular or subpleural distribution.

    View details for Web of Science ID 000075488200031

    View details for PubMedID 9722856

  • Unsuspected pulmonary embolism: Prospective detection on routine helical CT scans RADIOLOGY Gosselin, M. V., Rubin, G. D., Leung, A. N., Huang, J., Rizk, N. W. 1998; 208 (1): 209-215


    To determine the prevalence of unsuspected pulmonary embolism (PE) on routine thoracic helical computed tomographic (CT) scans and to quantify the improvement in PE detection by using a cine-paging mode on a workstation instead of hard-copy review.Seven hundred eighty-five patients referred for routine contrast medium-enhanced thoracic CT within 9 months were prospectively recruited. Helical CT was performed. Studies were prospectively interpreted by four radiologists. Two radiologists performed routine, undirected, hard-copy consensus review for official interpretation; two of three thoracic radiologists independently performed a dedicated workstation-based search for PE. The presence of PE involving the main, lobar, or segmental pulmonary arteries was assigned a score of 1-5 (1 = definitely negative, 5 = definitely positive) by each independent reviewer. Patients with a score of 4 or 5 underwent lower-extremity ultrasound, ventilation-perfusion scintigraphy, or both, followed by pulmonary CT angiography if the findings were still equivocal.Twelve (1.5%) of the 785 patients had unsuspected PE, with an inpatient prevalence of 5% (eight of 160) and an outpatient prevalence of 0.6% (four of 625). Of the 12 patients with unsuspected PE, 10 (83%) had cancer. Of the 81 inpatients with cancer, seven (9%) had unsuspected PE. A dedicated workstation-based search resulted in detection of PE in three more patients (25%) than did hard-copy interpretation.The prevalence of unsuspected PE was highest among inpatients with cancer. A directed, workstation-based search can improve the PE detection rate over that with hard-copy review.

    View details for Web of Science ID 000074296300033

    View details for PubMedID 9646815

  • Primary malignant pulmonary hemangiopericytoma CLINICAL IMAGING Katz, D. S., Lane, M. J., Leung, A. N., Marcus, F. S., Sakata, M. K. 1998; 22 (3): 192-195


    A primary malignant pulmonary hemangiopericytoma was diagnosed in a 45-year-old woman who complained of 10 months of cough and exertional dyspnea. One year after resection of the mass, a metastatic lesion was removed from the contralateral lung. The literature on this unusual pulmonary lesion is reviewed.

    View details for Web of Science ID 000072936200005

    View details for PubMedID 9559231

  • Bronchiolitis obliterans after lung transplantation - Detection using expiratory HRCT CHEST Leung, A. N., Fisher, K., Valentine, V., Girgis, R. E., Berry, G. J., Robbins, R. C., Theodore, J. 1998; 113 (2): 365-370


    The objective of this study was to determine if air trapping, as detected on expiratory high-resolution CT (HRCT), is useful as an indicator of bronchiolitis obliterans (BO) in lung transplant recipients. MATERIALS andCorresponding inspiratory and expiratory HRCT images at five different levels and spirometry were obtained in 21 lung transplant recipients. Eleven patients had BO proved by transbronchial biopsy specimens; the remaining 10 patients had no pathologic or functional evidence of airways disease. Two "blinded" observers assessed the inspiratory images for the presence of bronchiectasis and mosaic pattern of lung attenuation, and the expiratory images for presence and extent of air trapping. Statistical comparison of the frequency of HRCT findings between patients with and without BO was performed using Fisher's Exact Test.On inspiratory images, bronchiectasis and mosaic pattern of lung attenuation were present in 4 (36%) and 7 (64%) of 11 patients with BO, and 2 (20%) and 1 (10%) of 10 patients without BO (p>0.05 and p<0.05), respectively. The sensitivity, specificity, and accuracy of bronchiectasis and mosaic pattern for BO were 36%, 80%, and 57%, and 64%, 90%, and 70%, respectively. On expiratory images, air trapping was found in 10 of 11 (91%) patients with BO compared to 2 of 10 (20%) patients without BO (p<0.002). Air trapping was found to have a sensitivity of 91%, specificity of 80%, and accuracy of 86% for BO. Air trapping was identified in one patient with BO who had normal results of baseline spirometric function tests.Air trapping, as detected on expiratory HRCT, was the most sensitive and accurate radiologic indicator of BO in the lung transplant population.

    View details for Web of Science ID 000072002900022

    View details for PubMedID 9498953

  • Clinics in diagnostic imaging (27). Sarcoidosis. Singapore medical journal Leung, A. N. 1997; 38 (7): 302-304


    A 44-year-old Caucasian man presented with third-degree heart block. Chest radiograph and high-resolution computed tomography (HRCT) of the thorax showed mediastinal and bilateral hilar lymphadenopathy associated with a diffuse, bilateral micronodular pattern. The HRCT findings and differential diagnosis of sarcoidosis are reviewed.

    View details for PubMedID 9339099

  • Simulated dose reduction in conventional chest CT: Validation study RADIOLOGY Mayo, Whittall, K. P., Leung, A. N., Hartman, T. E., Park, C. S., Primack, S. L., Chambers, G. K., Limkeman, M. K., Toth, T. L., Fox, S. H. 1997; 202 (2): 453?57


    To validate a technique of computer-simulated dose reduction for conventional chest computed tomography (CT).In 27 patients, CT scans were obtained at 200, 100, and 40 mAs at two levels. The raw data from the 200-mAs scan were modified on a computer workstation to simulate the increased noise present on 100- and 40-mAs scans. Real and simulated 100- and 40-mAs images were independently assessed in random order for overall image quality and radiologic findings by four subspecialty-trained chest radiologists who were blinded to the technique. The four observers were given paired real and simulated images. They were asked to identify the real image and note any difference in diagnostic quality.No difference was seen in overall image quality or radiologic findings between real and simulated images (P > .05). In the paired comparison, 433 of 864 (50.1%) real images were correctly identified.Computer modification of 200-mAs raw scan data to simulate 100- and 40-mAs noise levels produces reconstructed images indistinguishable from real 100- and 40-mAs scans. This technique provides realistic reduced-dose images without patient radiation exposure and with identical image registration and motion artifact.

    View details for DOI 10.1148/radiology.202.2.9015073

    View details for Web of Science ID A1997WD82200029

    View details for PubMedID 9015073

  • Spiral CT of the thorax in daily practice: Optimization of technique JOURNAL OF THORACIC IMAGING Leung, A. N. 1997; 12 (1): 2-10


    Effective utilization of spiral computed tomography (CT) technology in imaging of the thorax requires an understanding of technical parameters that affect image and scan quality. This article discusses how operator-controlled scan parameters can be optimized to achieve diagnostic and cost-effective examinations appropriate for daily clinical practice.

    View details for Web of Science ID A1997WA70200002

    View details for PubMedID 8989754

  • MRI of pulmonary embolism using Gd-DTPA-polyethylene glycol polymer enhanced 3D fast gradient echo technique in a canine model MAGNETIC RESONANCE IMAGING Li, K. C., Pelc, L. R., NAPEL, S. A., Goris, M. L., Lin, D. T., SONG, C. K., Leung, A. N., Rubin, G. D., HOLLETT, M. D., Harris, D. P. 1997; 15 (5): 543-550


    This study was to evaluate the accuracy of MR angiography (MRA) using a Gd-DTPA-polyethylene glycol polymer (Gd-DTPA-PEG) with a 3D fast gradient echo (3D fgre) technique in diagnosing pulmonary embolism in a canine model. Pulmonary emboli were created in six mongrel dogs (20-30 kg) by injecting tantalum oxide-doped autologous blood clots into the femoral veins via cutdowns. MRI was performed with a 1.5 T GE Signa imager using a 3D fgre sequence (11.9/2.3/15 degrees) following intravenous injection of 0.06 mmol Gd/kg of Gd-DTPA-PEG. The dogs were euthanized and spiral CT of the lungs were then obtained on the deceased dogs. The MRI images were reviewed independently and receiver-operating-characteristic (ROC) curves were used for statistical analysis using spiral CT results as the gold standard. The pulmonary emboli were well visualized on spiral CT. Out of 108 pulmonary segments in the six dogs, 24 contained emboli >2 mm and 27 contained emboli < or = 2 mm. With unblinded review, MRI detected 79% of emboli >2 mm and only 48% of emboli < or = 2 mm. The blinded review results were significantly worse. Gd-DTPA-PEG enhanced 3D fgre MRI is potentially able to demonstrate pulmonary embolism with fairly high degree of accuracy, but specialized training for the interpretations will be required.

    View details for Web of Science ID A1997XM76800004

    View details for PubMedID 9253998

  • Radiologic manifestations of lymphoma in the thorax AMERICAN JOURNAL OF ROENTGENOLOGY Au, V., Leung, A. N. 1997; 168 (1): 93-98

    View details for Web of Science ID A1997VZ55500019

    View details for PubMedID 8976927

  • Optimization of thoracic spiral CT: Effects of iodinated contrast medium concentration RADIOLOGY Rubin, G. D., Lane, M. J., Bloch, D. A., Leung, A. N., Stark, P. 1996; 201 (3): 785-791


    To determine the effect of varying iodine concentration on arterial enhancement and perivenous artifact during thoracic spiral computed tomographic (CT) scanning.One hundred thirty-eight outpatients received 15.0 g (n = 76) or 22.5 g (n = 62) of iodine (300 mg/mL iodine) while undergoing thoracic spiral CT. Patients received either undiluted contrast medium, 1:1 normal saline dilution, or 3:1 normal saline dilution. Contrast medium was injected at a flow rate determined to deliver the entire iodine dose within 40 seconds. Attenuation was measured within arteries and veins. Three blinded thoracic radiologists independently graded perivenous artifact and arterial enhancement.Perivenous artifacts were statistically significantly reduced with successive iodine dilution (P < .002). Arterial enhancement was statistically significantly better with 15.0 g of iodine diluted 1:1 when compared with the same iodine dose undiluted or diluted 3:1 (P < .01). Arterial enhancement achieved with 15.0 g of iodine diluted 1:1 was not statistically significantly lower than that achieved with 22.5 g of iodine diluted 1:1 (P > .31); however, venous artifact was greater with 22.5 g of iodine (P < .004).Reduced iodine concentration appears to diminish perivenous artifact and to result in improved arterial enhancement during thoracic spiral CT.

    View details for Web of Science ID A1996VU50000033

    View details for PubMedID 8939232

  • Effects of lobar atelectasis on the distribution of pleural effusion and pneumothorax JOURNAL OF THORACIC IMAGING Stark, P., Leung, A. 1996; 11 (2): 145-149


    Atelectasis is known to change the retractility of the involved part of the lung and the pleural pressure adjacent to it. Consequently, pleural effusions or pneumothoraxes will change their distribution and preferentially migrate toward the site of atelectasis. This alteration will often result in an atypical distribution of pleural liquid or gas. The radiological implications of this phenomenon are discussed herein.

    View details for Web of Science ID A1996UP14200004

    View details for PubMedID 8820023

  • Pulmonary tuberculosis: Comparison of CT findings in HIV-seropositive and HIV-seronegative patients RADIOLOGY Leung, A. N., Brauner, M. W., Gamsu, G., MlikaCabanne, N., BenRomdhane, H., Carette, M. F., Grenier, P. 1996; 198 (3): 687?91


    To determine the differences in the computed tomographic (CT) appearance of pulmonary tuberculosis (TB) between patients with and patients without human immunodeficiency virus (HIV) infection.CT scans and chest radiographs of 42 HIV-seropositive and 42 HIV-seronegative patients with pulmonary TB were reviewed. CD4 T-lymphocyte counts, measured in 40 seropositive patients, were at least 200 cells per microliter in 10 patients and were less that 200 cells per microliter in 30.Seropositive patients had a higher prevalence of lymphadenopathy at chest radiography (P< .05). The seropositive patients had a lower prevalence of consolidation (P< .05), cavitation (P< .01), and postprimary pattern (P< .05) at CT. HIV-seropositive patients had a higher frequency of miliary (P< .01) and extrapulmonary disease (P< .001). Similar features of pulmonary TB were observed in seropositive patients with mild and severe immunosuppression.HIV-seropositive patients had a lower prevalence of localized parenchymal disease and a higher prevalence of disseminated disease at CT.

    View details for DOI 10.1148/radiology.198.3.8628855

    View details for Web of Science ID A1996TW21200013

    View details for PubMedID 8628855

  • Radiographic appearance of central venous catheters AMERICAN JOURNAL OF ROENTGENOLOGY Fisher, K. L., Leung, A. N. 1996; 166 (2): 329-337


    Central venous catheters (CVCs) are defined as venous access devices whose tips terminate in the superior or inferior vena cava, regardless of insertion site. CVCs allo reliable, painless, and repeated entry into the venous system and are commonly used for the administration of IV therapy, parenteral nutrition, and blood products as well as for the periodic blood sampling, hemodynamic monitoring, and hemodialysis. Catheter composition and design vary and depend on the duration of intended use and specific functions required. The purpose of this essay is to illustrate commonly used catheters, discuss factors governing catheter selection, and review important catheter-related complications.

    View details for Web of Science ID A1996TR34300018

    View details for PubMedID 8553941

  • VOLUMETRIC APPLICATIONS FOR SPIRAL CT IN THE THORAX Conference on Physiology and Function from Multidimensional Images Rubin, G. D., Napel, S., Leung, A. SPIE - INT SOC OPTICAL ENGINEERING. 1994: 353?360
  • INTRATHORACIC PEDIATRIC TUBERCULOSIS - A REPORT OF 202 CASES TUBERCLE AND LUNG DISEASE PINEDA, P. R., Leung, A., Muller, N. L., Allen, E. A., Black, W. A., FitzGerald, J. M. 1993; 74 (4): 261-266


    Until recently paediatric tuberculosis rates were in decline in developed countries, but more recently there has been a significant change in these trends. Tuberculosis in British Columbia (BC) is centralized and all paediatric cases diagnosed between 1979 and 1988 were reviewed. There were 252 notifications during the study period but 50 cases were excluded (31 extrapulmonary cases, 11 with missing records and 8 because of incorrect diagnoses). There were 109 (54%) female patients. The age range was 4 months-15 years (6.4 +/- 4.1 years). 52% were 5 years old or less. 75 (37.1%) were aboriginal Canadians, 61 (30.2%) were Asian, 50 (24.8%) were Caucasian and 16 (8%) were included in miscellaneous or unknown groups. Primary pulmonary disease occurred in 197 (97.5%); the remaining 5 had post-primary disease. A history of close contact was elicited in 158 children (78.2%). All but 8 (4%) had a positive PPD response to 5TU. 40% of children had symptoms, the most frequent being cough (51%) and fever (28.4%). Mycobacteriology was carried out in 169 (83.7%) children. Bacteriologic confirmation was achieved in 45 patients (22.2%). Chest X-rays were reviewed in 186 cases. Lymphadenopathy occurred in 93.5%, with hilar (34%) and combined hilar-paratracheal (26%) being the commonest findings. The majority of patients were treated with isoniazid and rifampin, with a minority receiving streptomycin or pyrazinamide in the initial intensive phase. 14 (6.9%) children had adverse reactions to their drugs but these were rapidly reversed with the withdrawal of the responsible drug. Response to therapy was excellent and there were no deaths.

    View details for Web of Science ID A1993LT95700007

    View details for PubMedID 8219178



    To correlate areas of parenchymal opacification on thin-section computed tomographic (CT) scans with histologic findings in patients with chronic infiltrative lung disease, the CT and histologic findings were evaluated in 29 patients with 11 such diseases. Open-lung biopsy was performed after CT. The area of predominant involvement was classified as air space, interstitium, or a mixture of both. A pathologic score of disease activity was assigned, and the extent of fibrosis was assessed whenever fibrosis was present. Parenchymal opacification on CT scans corresponded to abnormalities that affected mainly the air spaces in three patients (10%), the interstitium in 13 patients (45%), or both to a similar degree in 13 patients (45%). In 25 of 29 patients (86%), parenchymal opacification was associated with potentially treatable or reversible disease. Abnormalities considered irreversible were seen in three patients with end-stage fibrosis and one patient with talcosis. Parenchymal opacification on thin-section CT scans is a nonspecific finding in diseases that affect the air spaces, interstitium, or both but usually indicates potentially treatable or reversible disease.

    View details for Web of Science ID A1993LH28400040

    View details for PubMedID 8511299



    The aim of the study was to review the radiologic features of primary tuberculosis in childhood and to determine whether differences in patterns of disease occur among age and ethnic groups. Chest radiographs of 191 children with pediatric primary tuberculosis were reviewed by two observers. Lymphadenopathy, present in 92% of cases, was the most common abnormality identified on the initial chest radiograph and typically involved the hilar and paratracheal regions. Parenchymal abnormalities, identified in 70% of cases, occurred more commonly in the right lung (P less than .001). Children 0-3 years of age had a higher prevalence of lymphadenopathy (P less than .01) and a lower prevalence of parenchymal abnormalities (P less than .001) than older children. A lower prevalence of lymphadenopathy was found in whites than in nonwhites (P less than .02). The radiologic abnormalities often progressed in the initial follow-up. Lymphadenopathy, with or without concomitant parenchymal abnormality, is the radiologic hallmark of primary tuberculosis in childhood. However, distinct age-related and racial differences in presenting patterns of disease exist and should be recognized.

    View details for Web of Science ID A1992GW05400019

    View details for PubMedID 1727316



    We compared the accuracies of high-resolution CT (HRCT) and conventional CT in determining the specific diagnoses in 75 consecutive patients with chronic diffuse infiltrative lung disease. Without knowledge of clinical or pathologic data, two reviewers independently assessed three separate sets of CT scans in random order: three HRCT scans, three 10-mm collimation CT scans obtained at the same levels as the HRCT scans, and a complete conventional CT scan. The HRCT scans were obtained at the level of the aortic arch, tracheal carina, and 1 cm above the right hemidiaphragm by using 1.5-mm collimation and a high spatial resolution algorithm. Observers gave the most likely diagnosis along with their degree of diagnostic confidence. The correct diagnosis, irrespective of confidence level, was reached with 71% of the HRCT scans and with 72% of both the corresponding 10-mm and complete conventional CT scans. Confidence level 1 (definite) was reached with 49% of HRCT scans, 31% of corresponding 10-mm scans, and 43% of complete conventional CT examinations; the correct diagnosis was made in 92%, 96%, and 94% of those examinations, respectively. In none of the patients were findings on the limited HRCT scan normal when findings on the conventional CT scan were abnormal. We conclude that in most patients with chronic infiltrative lung disease a specific diagnosis can be made by obtaining a limited number of HRCT scans.

    View details for Web of Science ID A1991GF74300003

    View details for PubMedID 1892019



    The CT features of benign and malignant pleural diseases have been described. However, the accuracy of these features in the differential diagnosis of diffuse pleural disease has not been assessed before. Without knowledge of clinical or pathologic data, we reviewed the CT findings in 74 consecutive patients with proved diffuse pleural disease (39 malignant and 35 benign). The patients included 53 men and 21 women 23-78 years old. Features that were helpful in distinguishing malignant from benign pleural disease were (1) circumferential pleural thickening, (2) nodular pleural thickening, (3) parietal pleural thickening greater than 1 cm, and (4) mediastinal pleural involvement. The specificities of these findings were 100%, 94%, 94%, and 88%, respectively. The sensitivities were 41%, 51%, 36%, and 56%, respectively. Twenty-eight of 39 malignant cases (sensitivity, 72%; specificity, 83%) were identified correctly by the presence of one or more of these criteria. Malignant mesothelioma (n = 11) could not be reliably differentiated from pleural metastases (n = 24). We conclude that CT is helpful in the differential diagnosis of diffuse pleural disease, particularly in differentiation of malignant from benign conditions.

    View details for Web of Science ID A1990CN84800006

    View details for PubMedID 2106209

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