Bio

Clinical Focus


  • Diagnostic Radiology
  • Radiology

Academic Appointments


Professional Education


  • Fellowship:UCSF Medical Center (1989) CA
  • Residency:UCSF Medical Center (1988) CA
  • Fellowship:UCSF Medical Center (1988) CA
  • Board Certification: Diagnostic Radiology, American Board of Radiology (1988)
  • Internship:Pacific Presbyterian Med Ctr (1984) CA
  • Medical Education:Stanford University School of Medicine (1983) CA

Research & Scholarship

Current Research and Scholarly Interests


Body imaging utilizing CT, ultrasound and MRI; magnetic, resonance angiography; imaging of trauma; angiography,, interventional radiology and CT angiography, and imaging guidance of, invasive procedures using CT, ultrasound and magnetic resonance

Teaching

2013-14 Courses


Publications

Journal Articles


  • Sonography of the normal appendix: its varied appearance and techniques to improve its visualization. Ultrasound quarterly Ung, C., Chang, S. T., Jeffrey, R. B., Patel, B. N., Olcott, E. W. 2013; 29 (4): 333-341

    Abstract

    The sonographic identification of the normal appendix is crucial to the success of ultrasound as an effective screening method for diagnosing acute appendicitis. The normal appendix can be challenging to identify on sonography, however, because it is a narrow tubular structure and has variable sonographic appearances. Moreover, the tip of the appendix can be quite variable in location. In this article, we review the various sonographic appearances of the normal appendix and highlight strategies to improve its visualization.

    View details for DOI 10.1097/RUQ.0b013e3182a2aa8e

    View details for PubMedID 24263759

  • Sonographic Evaluation of Cervical Lymph Nodes in Papillary Thyroid Cancer ULTRASOUND QUARTERLY Shin, L. K., Olcott, E. W., Jeffrey, R. B., Desser, T. S. 2013; 29 (1): 25-32

    Abstract

    Sonography is the modality of choice for imaging cervical lymph nodes in patients with papillary thyroid cancer, both before surgery and for postoperative surveillance. Sonography is also an invaluable tool to guide fine-needle aspiration of abnormal nodes. Microcalcifications, cystic changes, abnormal morphology, and disordered vascularity are features of metastatic nodal involvement with papillary thyroid carcinoma and should be sought during surveillance scans as well as in targeting for fine-needle aspiration.

    View details for DOI 10.1097/RUQ.0b013e31827c7a9e

    View details for Web of Science ID 000315449400004

    View details for PubMedID 23358214

  • Three-dimensional volume-rendered multidetector CT imaging of the posterior inferior pancreaticoduodenal artery: its anatomy and role in diagnosing extrapancreatic perineural invasion. Cancer imaging Patel, B. N., Giacomini, C., Jeffrey, R. B., Willmann, J. K., Olcott, E. 2013; 13 (4): 580-590

    Abstract

    Extrapancreatic perineural spread in pancreatic adenocarcinoma contributes to poor outcomes, as it is known to be a major contributor to positive surgical margins and disease recurrence. However, current staging classifications have not yet taken extrapancreatic perineural spread into account. Four pathways of extrapancreatic perineural spread have been described that conveniently follow small defined arterial pathways. Small field of view three-dimensional (3D) volume-rendered multidetector computed tomography (MDCT) images allow visualization of small peripancreatic vessels and thus perineural invasion that may be associated with them. One such vessel, the posterior inferior pancreaticoduodenal artery (PIPDA), serves as a surrogate for extrapancreatic perineural spread by pancreatic adenocarcinoma arising in the uncinate process. This pictorial review presents the normal and variant anatomy of the PIPDA with 3D volume-rendered MDCT imaging, and emphasizes its role as a vascular landmark for the diagnosis of extrapancreatic perineural invasion from uncinate adenocarcinomas. Familiarity with the anatomy of PIPDA will allow accurate detection of extrapancreatic perineural spread by pancreatic adenocarcinoma involving the uncinate process, and may potentially have important staging implications as neoadjuvant therapy improves.

    View details for DOI 10.1102/1470-7330.2013.0051

    View details for PubMedID 24434918

  • Sonography for appendicitis: Nonvisualization of the appendix is an indication for active clinical observation rather than direct referral for computed tomography JOURNAL OF CLINICAL ULTRASOUND Stewart, J. K., Olcott, E. W., Jeffrey, R. B. 2012; 40 (8): 455-461

    Abstract

    To determine the prevalence of perforated and nonperforated appendicitis in patients with nonvisualization of the appendix on ultrasound (US) performed for suspected appendicitis, and to evaluate the value of CT in these patients.We analyzed 400 consecutive patients undergoing US for suspected appendicitis. Of these patients, 260 had nonvisualization of the appendix, but otherwise normal scans. We analyzed the clinical outcome in these patients to determine the prevalence of appendicitis, referrals for CT, and the contribution of CT in these patients.Of the 400 patients, 140 (35%) had either a normal (80 patients, 25%) or an abnormal appendix (60 patients, 15%); 260 (65%) had nonvisualization of the appendix. Overall 75 patients had appendicitis (18.8%) and 17 (4.3%) had appendicitis with perforation. Of the 260 patients with nonvisualization of the appendix, 14 patients (5.4%) had appendicitis and 2 were perforated (0.8%). The prevalence of perforated and nonperforated appendicitis in this group was significantly lower than the overall group (p < 0.001 and p < 0.01, respectively). Of these 260 patients, 101 patients (38.8%) had CT within 48 hours and 79 (78.2%) had normal scans.Patients with nonvisualization of the appendix on US, but otherwise normal scans, are at significantly lower risk for appendicitis, either perforated or nonperforated. Active clinical observation should be considered in these patients, rather than direct referral for CT.

    View details for DOI 10.1002/jcu.21928

    View details for Web of Science ID 000308645400001

    View details for PubMedID 22638942

  • Split-bolus MDCT urography with synchronous nephrographic and excretory phase enhancement AMERICAN JOURNAL OF ROENTGENOLOGY Chow, L. C., Kwan, S. W., Olcott, E. W., Sommer, G. 2007; 189 (2): 314-322

    Abstract

    Our purpose was to evaluate the utility of CT urography performed using a split contrast bolus that yields synchronous nephrographic and excretory phase enhancement.Five hundred consecutive patients referred for evaluation of possible urinary tract abnormalities (327 for painless hematuria) underwent CT urography with unenhanced scanning of the abdomen and pelvis and scanning during concurrent nephrographic and excretory phase enhancement produced by administration of a split contrast bolus. The enhanced abdomen scan was obtained with abdominal compression; the enhanced pelvis scan was obtained after release of compression. Findings from axial sections and coronal maximum intensity projections were correlated with clinical follow-up and, as available, with laboratory and other imaging studies including cystoscopy, ureteroscopy, urine cytology, surgery, and pathology. Follow-up management for each patient was determined by the clinical judgment of the referring physician.CT urography identified 100% of pathologically confirmed renal cell carcinomas (n = 10) and uroepithelial malignancies involving the renal collecting system or ureter (n = 8). An additional nine renal masses were identified for which no pathologic proof has yet been obtained, including eight subcentimeter solid renal masses and one multiloculated lesion. Fourteen of 19 confirmed cases of uroepithelial neoplasm involving the bladder were identified. CT urography yielded one false-positive for bladder tumor, two false-positives for ureteral tumor, and one patient with a bladder mass who refused further evaluation. CT urography yielded sensitivity and specificity of 100% and 99% and 74% and 99% and positive predictive value and negative predictive value of 80% and 100% and 93% and 99% for the renal collecting system and ureter and bladder, respectively. CT urography was ineffective in identifying 11 cases of noninfectious cystitis. CT urography also depicted numerous other congenital and acquired abnormalities of the urinary tract.Split-bolus MDCT urography detected all proven cases of tumors of the upper urinary tract, yielding high sensitivity and specificity. The split-bolus technique has the potential to reduce both radiation dose and the number of images generated by MDCT urography.

    View details for DOI 10.2214/AJR.07.2288

    View details for Web of Science ID 000248624400012

    View details for PubMedID 17646456

  • CT colonography: Influence of 3D viewing and polyp candidate features on interpretation with computer-aided detection RADIOLOGY Shi, R., Schraedley-Desmond, P., Napel, S., Olcott, E. W., Jeffrey, R. B., Yee, J., Zalis, M. E., Margolis, D., Paik, D. S., Sherbondy, A. J., Sundaram, P., Beaulieu, C. F. 2006; 239 (3): 768-776

    Abstract

    To retrospectively determine if three-dimensional (3D) viewing improves radiologists' accuracy in classifying true-positive (TP) and false-positive (FP) polyp candidates identified with computer-aided detection (CAD) and to determine candidate polyp features that are associated with classification accuracy, with known polyps serving as the reference standard.Institutional review board approval and informed consent were obtained; this study was HIPAA compliant. Forty-seven computed tomographic (CT) colonography data sets were obtained in 26 men and 10 women (age range, 42-76 years). Four radiologists classified 705 polyp candidates (53 TP candidates, 652 FP candidates) identified with CAD; initially, only two-dimensional images were used, but these were later supplemented with 3D rendering. Another radiologist unblinded to colonoscopy findings characterized the features of each candidate, assessed colon distention and preparation, and defined the true nature of FP candidates. Receiver operating characteristic curves were used to compare readers' performance, and repeated-measures analysis of variance was used to test features that affect interpretation.Use of 3D viewing improved classification accuracy for three readers and increased the area under the receiver operating characteristic curve to 0.96-0.97 (P<.001). For TP candidates, maximum polyp width (P=.038), polyp height (P=.019), and preparation (P=.004) significantly affected accuracy. For FP candidates, colonic segment (P=.007), attenuation (P<.001), surface smoothness (P<.001), distention (P=.034), preparation (P<.001), and true nature of candidate lesions (P<.001) significantly affected accuracy.Use of 3D viewing increases reader accuracy in the classification of polyp candidates identified with CAD. Polyp size and examination quality are significantly associated with accuracy.

    View details for Web of Science ID 000237738600018

    View details for PubMedID 16714460

  • Measurement of renal extraction fraction with contrast-enhanced CT RADIOLOGY Sommer, G., Olcott, E. W., Chow, L. C., Saket, R. R., Schraedley-Desmond, P. 2005; 236 (3): 1029-1033

    Abstract

    Study was approved by the institutional review board, and informed patient consent was waived. A method for minimization of sources of variability in measuring single-kidney extraction fraction (EF) was determined retrospectively with contrast material-enhanced computed tomography (CT). Ten adults underwent CT of the kidneys; precontrast scans were obtained, followed by postcontrast scanning 2 minutes after contrast material injection. Single-kidney EF was then calculated for each patient with the formula EF = (CT(A) - CT(V))/(CT(A) - CT(PRE)), where CT(A) and CT(V) are the postcontrast CT values (in Hounsfield units) of the systemic blood and renal venous blood, respectively, and CT(PRE) is the precontrast CT value of the blood. Both conventional two-dimensional and volumetric three-dimensional regions of interest were used for determining mean CT values of the blood. By using the volumetric regions of interest, left and right renal EF values averaged 17.3% and 18.0%, respectively, for two observers, compared with the accepted value of 15%-20%. This latter technique also minimized right-left kidney and interobserver variability in the measurement of EF.

    View details for DOI 10.1148/radiol.2363041371

    View details for Web of Science ID 000231412600039

    View details for PubMedID 16020561

  • Computed tomography colonography - Feasibility of computer-aided polyp detection in a "First reader" paradigm JOURNAL OF COMPUTER ASSISTED TOMOGRAPHY Mani, A., Napel, S., Paik, D. S., Jeffrey, R. B., Yee, J., Olcott, E. W., Prokesch, R., Davila, M., Schraedley-Desmond, P., Beaulieu, C. F. 2004; 28 (3): 318-326

    Abstract

    : To determine the feasibility of a computer-aided detection (CAD) algorithm as the "first reader" in computed tomography colonography (CTC).: In phase 1 of a 2-part blind trial, we measured the performance of 3 radiologists reading 41 CTC studies without CAD. In phase 2, readers interpreted the same cases using a CAD list of 30 potential polyps.: Unassisted readers detected, on average, 63% of polyps > or =10 mm in diameter. Using CAD, the sensitivity was 74% (not statistically different). Per-patient analysis showed a trend toward increased sensitivity for polyps > or =10 mm in diameter, from 73% to 90% with CAD (not significant) without decreasing specificity. Computer-aided detection significantly decreased interobserver variability (P = 0.017). Average time to detection of the first polyp decreased significantly with CAD, whereas total reading case reading time was unchanged.: Computer-aided detection as a first reader in CTC was associated with similar per-polyp and per-patient detection sensitivity to unassisted reading. Computer-aided detection decreased interobserver variability and reduced the time required to detect the first polyp.

    View details for Web of Science ID 000221234500003

    View details for PubMedID 15100534

  • Rapid measurement of time-averaged blood flow using ungated spiral phase-contrast MAGNETIC RESONANCE IN MEDICINE Park, J. B., Olcott, E. W., Nishimura, D. G. 2003; 49 (2): 322-328

    Abstract

    A novel ungated spiral phase-contrast (USPC) imaging method was developed for rapid measurement of time-averaged blood-flow rates in the presence of pulsatility. The spatial point-spread function was analyzed to provide an intuitive understanding of how spiral trajectories, which sample the k-space origin at every excitation, can mitigate the effects of pulsatility. Pulsatile flow phantom experiments were performed to validate the accuracy and repeatability of the USPC method. The measurement of flow in the renal and femoral arteries of normal volunteers were also performed. The phantom results (error < or = +9%, SD(phantom) < or = 2%, time-averaged pulsatile-flow rates = 3-15 ml/s) and in vivo results (SD(renal) < or = 8%, SD(femoral) < or = 14%) demonstrate the potential of the USPC method for rapidly and repeatedly measuring accurate time-averaged blood flow even in relatively small arteries and in the presence of strong pulsatility.

    View details for DOI 10.1002/mrm.10369

    View details for Web of Science ID 000180807100016

    View details for PubMedID 12541253

  • Imaging of skeletal muscle function using (18)FDG PET: force production, activation, and metabolism JOURNAL OF APPLIED PHYSIOLOGY Pappas, G. P., Olcott, E. W., Drace, J. E. 2001; 90 (1): 329-337

    Abstract

    The purpose of this study was to determine whether [(18)F]fluorodeoxyglucose (FDG) positron emission tomography (PET) can be used to evaluate muscle force production, create anatomic images of muscle activity, and resolve the distribution of metabolic activity within exercising skeletal muscle. Seventeen subjects performed either elbow flexion, elbow extension, or ankle plantar flexion after intravenous injection of FDG. PET imaging was performed subsequently, and FDG uptake was measured in skeletal muscle for each task. A fivefold increase in resistance during elbow flexion increased FDG uptake in the biceps brachii by a factor of 4. 9. Differences in relative FDG uptake were demonstrated as exercise tasks and loads were varied, permitting differentiation of active muscles. The intramuscular distribution of FDG within exercising biceps brachii varied along the transverse and longitudinal axes of the muscle; coefficients of variation along these axes were 0.39 and 0.23, respectively. These findings suggest FDG PET is capable of characterizing task-specific muscle activity and measuring intramuscular variations of glucose metabolism within exercising skeletal muscle.

    View details for Web of Science ID 000167547600042

    View details for PubMedID 11133926

  • Focal liver lesions: Pattern-based classification scheme for enhancement at arterial phase CT RADIOLOGY Nino-Murcia, M., Olcott, E. W., Jeffrey, R. B., Lamm, R. L., Beaulieu, C. F., Jain, K. A. 2000; 215 (3): 746-751

    Abstract

    To present our early experience with a classification scheme for categorizing focal liver lesions on the basis of the enhancement patterns that they exhibit in the arterial phase of computed tomography (CT) and to determine whether particular enhancement patterns suggest particular diagnoses.The authors reviewed arterial phase CT images in 100 consecutive patients with focal liver lesions, excluding simple cysts. The enhancement pattern of the dominant or representative lesion in each patient was classified into one of five categories-homogeneous, abnormal internal vessels or variegated, peripheral puddles, complete ring, or incomplete ring-by three radiologists blinded to the proved diagnosis. Lesions without enhancement were recorded separately. Agreement was reached by consensus in all cases. Standards of reference included findings at histologic examination, correlative imaging, or clinical and imaging follow-up.Ninety-two percent of the 100 lesions demonstrated arterial phase enhancement. Patterns associated with positive predictive values of 82% or greater and specificity of 80% or greater included abnormal internal vessels or variegated (hepatocellular carcinoma), peripheral puddles (hemangioma), and complete ring (metastasis).The appearance of hepatic lesions in the arterial phase of enhancement has potential use in the determination of specific diagnoses. The classification scheme used in this study may be a useful tool for the interpretation of arterial phase CT studies.

    View details for Web of Science ID 000087247000020

    View details for PubMedID 10831693

  • Aortic aneurysmal disease: Assessment of stent-graft treatment - CT versus conventional angiography RADIOLOGY Armerding, M. D., Rubin, G. D., Beaulieu, C. F., Slonim, S. M., Olcott, E. W., Samuels, S. L., Jorgensen, M. J., Semba, C. P., Jeffrey, R. B., Dake, M. D. 2000; 215 (1): 138-146

    Abstract

    To compare computed tomographic (CT) angiography and conventional angiography for determining the success of endoluminal stent-graft treatment of aortic aneurysms.Forty patients underwent conventional angiography and CT angiography following treatment of aortoiliac aneurysms with endoluminal stent-grafts. Six additional sets of conventional angiographic-CT angiographic examinations were performed in five patients after placement of additional stent-grafts or coil embolization to treat perigraft leakage. Three faculty CT radiologists who were blinded to patient clinical data and outcome independently interpreted the CT angiograms, and three faculty angiographers, who were not involved in the stent-graft deployment, interpreted the conventional angiograms. Images were assessed for the presence of postdeployment complications. A reference standard was developed by experienced radiologists using all available images and clinical data. Sensitivities, specificities, and kappa values were calculated.Perigraft leakage was the most commonly identified complication. Twenty perigraft leaks were detected in the results of 46 examinations. Sensitivities and specificities for detecting perigraft leakage were 63% and 77% for conventional angiography and 92% and 90% for CT angiography, respectively. The kappa value was 0. 41 for conventional angiography and 0.81 for CT angiography.CT angiography is the preferred method for establishing the presence of perigraft leakage following treatment of aortoiliac aneurysms with stent-grafts.

    View details for Web of Science ID 000086156700021

    View details for PubMedID 10751479

  • High-resolution three-dimensional in vivo imaging of atherosclerotic plaque MAGNETIC RESONANCE IN MEDICINE Luk-Pat, G. T., Gold, G. E., Olcott, E. W., Hu, B. S., Nishimura, D. G. 1999; 42 (4): 762-771

    Abstract

    The internal structure of atherosclerotic-plaque lesions may be a useful predictor of which lesions will rupture and cause sudden events such as heart attack or stroke. With lipid and flow suppression, we obtained high-resolution, three-dimensional (3D) images of atherosclerotic plaque in vivo that show the cap thickness and core size of the lesions. 3D GRASE was used because it provides flexible T(2) contrast and good resistance to off-resonance artifacts. While 2D RARE has similar properties, its resolution in the slice-select direction, which is important because of the irregular geometry of atherosclerotic lesions, is limited by achievable slice-excitation profiles. Also, 2D imaging generally achieves lower SNR than 3D imaging because, for SNR purposes, 3D image data is averaged over all the slices of a corresponding multislice 2D dataset. Although 3D RARE has many of the advantages of 3D GRASE, it requires a longer scan time because it uses more refocusing pulses to acquire the same amount of data. Finally, cardiac gating is an important part of our imaging sequence, but can make the imaging time quite long. To obtain reasonable scan times, a 2D excitation pulse was used to restrict the field of view. Magn Reson Med 42:762-771, 1999.

    View details for Web of Science ID 000082944400019

    View details for PubMedID 10502766

  • Flow quantification using low-spatial-resolution and low-velocity-resolution velocity images MAGNETIC RESONANCE IN MEDICINE Tsai, C. H., Olcott, E. W., Nishimura, D. G. 1999; 42 (4): 682-690

    Abstract

    In this report, a flow-quantification method using Fourier velocity encoding (FVE) with limited spatial and velocity resolution is presented. The total flow rate in a vessel corresponds to the first moment of the velocity histogram of spins in the vessel, whereas the spin density of flowing spins is the normalization constant. Because the measured histogram using FVE is distorted by RF saturation effects, the RF saturation effects are first estimated and then accurately compensated by acquiring five velocity-encoded images. The spatial resolution in each image can be relatively low because all stationary spins vanish in the resultant flow map. In a phantom study, the errors in measured flow rates were within +/-10% even when the pixel size was greater than the vessel size. This method was also successfully applied to measure flow in the femoral artery. In general, this method constitutes a basis for analyzing multiple velocity-encoded images and is particularly useful for quantifying slow flow or flow in small vessels. Magn Reson Med 42:682-690, 1999.

    View details for Web of Science ID 000082944400009

    View details for PubMedID 10502756

  • Advantages bf performing sonourethrography with lidocaine hydrochloride jelly in a prepackaged delivery system AMERICAN JOURNAL OF ROENTGENOLOGY Desser, T. S., Nino-Murcia, M., Olcott, E. W., Terris, M. K. 1999; 173 (1): 39-40

    View details for Web of Science ID 000081010900009

    View details for PubMedID 10397096

  • Liver tumors: Utility of characterization at dual-frequency US RADIOLOGY Sommer, G., Olcott, E. W., Tai, L. 1999; 211 (3): 629-636

    Abstract

    To evaluate the potential utility of a technique for analysis of ultrasonographic (US) images obtained at two center frequencies in a phantom model and in a clinical study of liver tumors.A US phantom was built that contained target regions with polystyrene scatterers both smaller and larger than scatterers in the background material. High- and low-frequency US images of target regions were obtained, and changes in the contrast-to-noise ratio (CNR) of the targets relative to the background were determined. In a clinical evaluation, 12 hemangiomas, 13 liver metastases, one adenoma, and two hepatomas were evaluated in a similar manner, and the results were correlated with the histologic findings in resected lesions.For targets containing scatterers smaller than those in the background, there was an increase in CNR of higher frequency images. The converse was true for target regions having scatterers larger than those in the background. Liver metastases generally showed an increase in CNR of higher frequency images, whereas hemangiomas generally showed somewhat decreased CNR of higher frequency images, differing significantly from metastases (P < .01-.001).Changes in CNRs of relatively high- and low-frequency US images may give useful information on the frequency dependence of backscattering, which is descriptive of the histologic findings in lesions and which is not evident with conventional US images.

    View details for Web of Science ID 000080446000007

    View details for PubMedID 10352584

  • Unenhanced CT in the evaluation of urinary calculi: Application of advanced computer methods SEMINARS IN ULTRASOUND CT AND MRI Olcott, E. W., Sommer, F. G. 1999; 20 (2): 136-141

    Abstract

    Recent advances in computer hardware and software technology enable radiologists to examine tissues and structures using three-dimensional figures constructed from the multiple planar images acquired during a spiral CT examination. Three-dimensional CT techniques permit the linear dimensions of renal calculi to be determined along all three coordinate axes with a high degree of accuracy and enable direct volumetric analysis of calculi, yielding information that is not available from any other diagnostic modality. Additionally, three-dimensional techniques can help to identify and localize calculi in patients with suspected urinary colic.

    View details for Web of Science ID 000079764600008

    View details for PubMedID 10222520

  • Ultra-short echo-time 2D time-of-flight MR angiography using a half-pulse excitation MAGNETIC RESONANCE IN MEDICINE Nielsen, H. T., Gold, G. E., Olcott, E. W., Pauly, J. M., Nishimura, D. G. 1999; 41 (3): 591-599

    Abstract

    Flow-related artifacts remain a significant concern for magnetic resonance (MR) angiography because their appearance in angiograms adversely impacts accuracy in evaluation of arterial stenoses. In this paper, a half-pulse excitation scheme for improved two-dimensional time-of-flight (2D TOF) angiography is described. The proposed method eliminates the need for gradient moment nulling (of all orders), providing significant reductions in spin dephasing and consequent artifactual signal loss. Furthermore, because the post-excitation refocusing and flow compensation gradients are obviated, the achievable echo time is dramatically shortened. The half-pulse excitation is employed in conjunction with a fast radial-line acquisition, allowing ultra-short echo times on the order of 250-300 microsec. Radial-line acquisition methods also provide additional benefits for flow imaging: effective mitigation of pulsatile flow artifacts, full k-space coverage, and decreased scan times. The half-pulse excitation/radial-line sequence demonstrated improved performance in initial clinical evaluations of the carotid bifurcation when compared with a conventional 2D TOF sequence.

    View details for Web of Science ID 000079317800023

    View details for PubMedID 10204884

  • Effects of niacin therapy that simulate neoplasia: Hepatic steatosis with concurrent hepatic dysfunction JOURNAL OF COMPUTER ASSISTED TOMOGRAPHY Kristensen, T., Olcott, E. W. 1999; 23 (2): 314-317

    Abstract

    Niacin, a widely used antihyperlipidemic agent, can produce hepatic steatosis and clinical hepatic abnormalities that together simulate the presentation of hepatobiliary neoplasia. We describe a patient initially suspected of having hepatobiliary neoplasia for whom imaging studies played a pivotal role in reaching the correct diagnosis of niacin-induced hepatotoxicity. Radiologists should become knowledgeable of these niacin-related effects, add niacin effects to the differential diagnosis of hepatic steatosis, and understand the value of correlative imaging in distinguishing these effects from hepatobiliary neoplasia.

    View details for Web of Science ID 000079202400025

    View details for PubMedID 10096345

  • Differentiation of hepatic malignancies from hemangiomas and cysts by T2 relaxation times: Early experience with multiply refocused four-echo imaging at 1.5 T JOURNAL OF MAGNETIC RESONANCE IMAGING Olcott, E. W., Li, K. C., Wright, G. A., Pattarelli, P. P., Katz, D. S., Ch'en, I. Y., Daniel, B. L. 1999; 9 (1): 81-86

    Abstract

    The purpose of this study was to examine hepatic lesions with a sequence designed to yield improved T2 measurements and evaluate the clinical utility of these measurements in distinguishing malignant from benign disease. Using a modified Carr-Purcell sequence incorporating features designed to compensate for imperfections in the imaging system, including a train of refocusing pulses emitted in an MLEV pattern oriented in composite fashion along all three coordinate axes, and a single spatially selective pulse placed immediately before a spiral readout, 14 benign lesions and 13 malignant lesions were evaluated prospectively with a conventional 1.5 T imager. The maximum, minimum, and mean T2 values of malignant lesions, hemangiomas, and cysts exceeded corresponding published values from spin-echo and echoplanar studies. The mean T2 value of the malignant lesions differed significantly (P < 0.0001) from those of hemangiomas and cysts. All malignant lesions and all benign lesions were distinguishable by their T2 values, which had ranges of no greater than 118.6 msec and no less than 134.3 msec, respectively. This early experience suggests that improved T2 measurements can facilitate the differentiation of hepatic malignancies from hemangiomas and cysts.

    View details for Web of Science ID 000080144300011

    View details for PubMedID 10030654

  • Urinary bladder pseudolesions on contrast-enhanced helical CT: Frequency and clinical implications AMERICAN JOURNAL OF ROENTGENOLOGY Olcott, E. W., Nino-Murcia, M., Rhee, J. S. 1998; 171 (5): 1349-1354

    Abstract

    The goals of this study were to define the distinguishing characteristics and frequency of urinary bladder pseudolesions that are produced as opacified urine enters the bladder during contrast-enhanced helical CT of the abdomen and to evaluate the usefulness of delayed imaging in differentiating pseudolesions from true lesions.Contrast-enhanced routine CT scans of 184 patients were obtained prospectively. For each patient, we also obtained 5-min delayed images of the bladder. The images were evaluated for apparent focal thickening or polypoid lesions involving the bladder wall, findings that may represent bladder neoplasia, without knowledge of the indications for the scan, the patient's clinical history, or the patient's diagnosis. Apparent lesions that were visible on routine images and entirely absent on delayed images were considered to be pseudolesions.Apparent lesions were identified on 20 (10.9%+/-4.5% [limits of the 95% confidence interval]) of the routine CT scans. Using delayed images, the 21 apparent lesions in these 20 patients were resolved as 13 pseudolesions and eight true lesions. Pseudolesions were present in 6.5%+/-3.6% of patients.Pseudolesions of the bladder that are indistinguishable from true lesions pose a significant clinical problem in routine contrast-enhanced helical CT of the abdomen. Delayed imaging of the bladder is useful in distinguishing pseudolesions from true lesions.

    View details for Web of Science ID 000076580400036

    View details for PubMedID 9798877

  • Pictorial essay - Dual-phase helical CT of locally invasive pancreatic adenocarcinoma JOURNAL OF COMPUTER ASSISTED TOMOGRAPHY Nino-Murcia, M., Olcott, E. W., Jeffrey, R. B. 1998; 22 (2): 282-287

    Abstract

    Dual-phase helical CT permits imaging of the pancreas and the peripancreatic structures in the arterial dominant and portal venous phases of enhancement, providing information crucial in the assessment of the local extent of pancreatic adenocarcinoma. This essay reviews the dual-phase helical CT findings of local extension that preclude potentially curative surgery, including vascular involvement, ligamentous or mesenteric invasion, extension of the tumor to involve the stomach or duodenum, and invasion of adjacent solid organs.

    View details for Web of Science ID 000072592200022

  • Power Doppler imaging in preoperative planning and postoperative monitoring of muscle flaps JOURNAL OF CLINICAL ULTRASOUND Loh, N. N., Chen, I. Y., Olcott, E., Jeffrey, R. B., Hui, K. C., PERSONS, B., Lineaweaver, W. C. 1997; 25 (9): 465-471

    Abstract

    We assessed the utility of power Doppler imaging (PDI) in preoperative planning and postoperative evaluation of microvascular tissue transfers.Twenty-five PDI studies were performed on 23 patients using a 5-10-MHz linear-array transducer. Thirteen patients were assessed preoperatively for patency of the desired donor vessel; 8 of them had surgical scars overlying the desired vascular territory. Twelve patients (including 2 from the first group) were evaluated postoperatively for patency of the vascular anastomoses and adequacy of the blood supply to the transferred tissue.Twelve of the 13 patients assessed preoperatively had successful flap transfers. Four of the 8 patients with scars over the desired vascular territories had absent or aberrant arteries, necessitating a change in the operative plan. None of these patients had operative complications. Eight of the 12 patients scanned postoperatively had patent anastomoses. In 2 of these patients, impending surgery was averted when the adequacy of the tissue blood supply was established with PDI. In 4 patients, PDI showed arterial or venous compromise, which was confirmed at surgery.PDI is a useful technique in microsurgical tissue transfer for assessing the patency of desired donor vessels preoperatively and for postoperative evaluation of blood supply.

    View details for Web of Science ID A1997YC38100001

    View details for PubMedID 9350564

  • An unusual acute compression fracture of the thoracolumbar spine ORTHOPEDICS Cheng, J. C., Olcott, E. W., Paiement, G. D. 1997; 20 (10): 975-977

    View details for Web of Science ID A1997YD67200011

    View details for PubMedID 9362082

  • Three-dimensional flow-independent peripheral angiography MAGNETIC RESONANCE IN MEDICINE Brittain, J. H., Olcott, E. W., Szuba, A., Gold, G. E., Wright, G. A., Irarrazaval, P., Nishimura, D. G. 1997; 38 (3): 343-354

    Abstract

    A magnetization-prepared sequence, T2-Prep-IR, exploits T1, T2, and chemical shift differences to suppress background tissues relative to arterial blood. The resulting flow-independent angiograms depict vessels with any orientation and flow velocity. No extrinsic contrast agent is required. Muscle is the dominant source of background signal in normal volunteers. However, long-T2 deep venous blood and nonvascular fluids such as edema also contribute background signal in some patients. Three sets of imaging parameters are described to address patient-specific contrast requirements. A rapid, spiral-based, three-dimensional readout is utilized to generate high-resolution angiograms of the lower extremities. Comparisons with x-ray angiography and two-dimensional time-of-flight angiography indicate that this flow-independent technique has unique capabilities to accurately depict stenoses and to visualize slow flow and in-plane vessels.

    View details for Web of Science ID A1997XW16200001

    View details for PubMedID 9339435

  • Accuracy of detection and measurement of renal calculi: In vitro comparison of three-dimensional spiral CT, radiography, and nephrotomography RADIOLOGY Olcott, E. W., Sommer, F. G., Napel, S. 1997; 204 (1): 19-25

    Abstract

    To compare accuracy of three-dimensional (3D) spiral computed tomography (CT) performed without administration of contrast material with that of radiography and linear nephrotomography in detection and measurement of renal calculi.Fifty renal calculi within an abdominal phantom were imaged with 3D spiral CT, radiography, and linear nephrotomography. Spiral CT data were analyzed with workstation-based 3D imaging software, with a thresholding procedure based on the maximally attenuating voxel within each calculus during measurement. Measurement accuracy and detection rates were compared according to modality. Conventional and magnification-corrected measurements from radiography and linear nephrotomography were included.Spiral CT depicted calculi and allowed determination of the collective two-dimensional and 3D linear measurements statistically significantly more accurately than the other techniques; the mean linear measurement errors along individual axes did not exceed 3.6%. With 3D spiral CT, calculus volumes were determined with a mean error of -4.8%.3D spiral CT enabled highly accurate determination of the volumes and all three linear dimensions of renal calculi. In addition, 3D spiral CT depicted calculi more sensitively than traditional techniques and provided new information and improved accuracy in the evaluation of nephrolithiasis.

    View details for Web of Science ID A1997XF19400008

    View details for PubMedID 9205217

  • Still the great mimicker: Abdominal tuberculosis AMERICAN JOURNAL OF ROENTGENOLOGY Jadvar, H., Mindelzun, R. E., Olcott, E. W., Levitt, D. B. 1997; 168 (6): 1455-1460

    Abstract

    Since the mid 1980s, a resurgence of tuberculosis has occurred. The disease is and will remain a serious public health threat worldwide. The clinical and radiologic features of abdominal tuberculosis may mimic those of many diseases. Radiologists evaluating abdominal images should consider the diagnosis of abdominal tuberculosis in immigrants from areas endemic for tuberculosis, in immunocompromised patients, and in high-risk patients such as the homeless. Imaging features that suggest the correct diagnosis are cecal amputation, ileocecal thickening and inflammation, shortening of the ascending colon, gaping of the ileocecal valve, mesenteric adenopathy, a misty mesentery, diffuse omental infiltration, loculate high-density ascites, an enhancing peritoneum with or without an omental line, nodularity of the surface of the mesenteric leaves, and transperitoneal permeation.

    View details for Web of Science ID A1997XA55300013

    View details for PubMedID 9168707

  • Volume rendering of CT data: Applications to the genitourinary tract AMERICAN JOURNAL OF ROENTGENOLOGY Sommer, F. G., Olcott, E. W., Chen, I., Beaulieu, C. F. 1997; 168 (5): 1223-1226

    View details for Web of Science ID A1997WV56800017

    View details for PubMedID 9129415

  • Do arterial phase helical CT images improve detection or characterization of colorectal liver metastases? JOURNAL OF COMPUTER ASSISTED TOMOGRAPHY Chen, I. Y., Katz, D. S., Jeffrey, R. B., Daniel, B. L., Li, K. C., Beaulieu, C. F., Mindelzun, R. E., Yao, D., Olcott, E. W. 1997; 21 (3): 391-397

    Abstract

    Our goal was to determine if arterial phase images from dual phase helical CT improve either the detection or the characterization of hepatic metastases in patients with colorectal carcinoma. Sixty-two patients with known colorectal cancer underwent 65 dual phase helical CT examinations to evaluate for possible liver metastases. Three blinded reviewers independently evaluated the portal venous phase images alone to determine if hepatic metastases were present or absent. Arterial phase images were then analyzed to determine if they identified additional lesions or aided in characterizing small hepatic lesions. Scores of the two methods for diagnosing metastases were compared with the "gold standard" established by a consensus panel of three other radiologists who reviewed all images together with clinical, pathologic, and other imaging data. The addition of arterial phase imaging did not detect any new metastases. However, in 6 of the 64 technically adequate examinations, hepatic arterial phase images increased lesion conspicuity and significantly increased diagnostic confidence when compared with portal vein phase scans alone. In patients with colorectal cancer, the addition of arterial phase imaging does not increase sensitivity, but improves the specificity in diagnosing liver metastases in a small number of cases. Dual phase helical CT does not appear to be indicated in the evaluation of liver metastases from colorectal cancer.

    View details for Web of Science ID A1997WV86400010

    View details for PubMedID 9135646

  • Power versus color Doppler sonography of the normal cystic artery: Implications for patients with acute cholecystitis AMERICAN JOURNAL OF ROENTGENOLOGY Olcott, E. W., Jeffrey, R. B., Jain, K. A. 1997; 168 (3): 703-705

    Abstract

    The purposes of this investigation were to compare prospectively the pattern and extent of cystic artery flow revealed by power Doppler sonography and color Doppler sonography in patients with normal gallbladders and to analyze the potential implications of these findings for power Doppler sonography in diagnosing acute cholecystitis.The cystic arteries of 142 patients (79 women and 63 men) with normal gallbladders were imaged with both power Doppler sonography and color Doppler sonography using 5-MHz transducers and settings optimized to reveal low-volume flow. The presence or absence of cystic artery flow and the anatomic extent of its visualization were recorded for each patient.Power Doppler sonography revealed flow in 73% of patients with normal gallbladders compared with 53% revealed by color Doppler sonography. Cystic artery flow within the distal fundal quartile was revealed by power Doppler sonography in 20% of patients and flow spanning greater than 50% of the anterior gallbladder wall was revealed by power Doppler sonography in 17% of patients. These findings differed from those of color Doppler sonography at a highly significant level (p < .0001, chi-square test).Power Doppler sonography is significantly more sensitive than color Doppler sonography for revealing cystic artery flow in patients with normal gallbladders. The flow patterns in patients with normal gallbladders obtained with power Doppler sonography overlap flow patterns previously reported as fairly specific criteria for diagnosing acute cholecystitis using color Doppler sonography, namely, flow within the distal fundal quartile and flow spanning greater than 50% of the anterior gallbladder wall. Accordingly, these color Doppler sonography criteria are not applicable to the diagnosis of acute cholecystitis with power Doppler sonography. Different power Doppler sonography criteria are necessary for the diagnosis of acute cholecystitis.

    View details for Web of Science ID A1997WJ62800027

    View details for PubMedID 9057519

  • Improved 2D time-of-flight angiography using a radial-line k-space acquisition MAGNETIC RESONANCE IN MEDICINE Nielsen, H. T., Olcott, E. W., Nishimura, D. G. 1997; 37 (2): 285-291

    Abstract

    For flow imaging applications, radial-line k-space acquisition methods offer advantages over conventional 2DFT methods. Specifically, radial-line acquisition methods mitigate artifacts resulting from pulsatile flow while offering a potential reduction in scan times. In this paper, radial-line and 2DFT acquisitions are compared in a two-dimensional time-of-flight angiography sequence. The twisting radial-line (TwiRL) trajectory, a variant of 2D projection reconstruction, is used to represent the family of radial-line trajectories. In both phantom and in vivo studies, the TwiRL images demonstrate improved vessel depiction including a more uniform signal intensity and better delineation of the vasculature in comparison with images obtained via the 2DFT method.

    View details for Web of Science ID A1997WD27200020

    View details for PubMedID 9001154

  • IMAGING OF BLUNT HEPATIC-TRAUMA RADIOLOGIC CLINICS OF NORTH AMERICA Jeffrey, R. B., Olcott, E. W. 1991; 29 (6): 1299-1310

    Abstract

    This article focuses on the clinical role of high resolution computed tomography (CT) in the initial diagnosis and management of hemodynamically stable patients with blunt hepatic trauma. The increased utilization and diagnostic confidence afforded by CT has dramatically changed the surgical approach and need for laparatomy. The most important development has been the growing realization by many trauma surgeons that nonoperative management is often successful in stable patients who have CT evidence of isolated blunt hepatic trauma.

    View details for Web of Science ID A1991GN74000011

    View details for PubMedID 1947047

  • DETECTION OF ACTIVE INTRAABDOMINAL ARTERIAL HEMORRHAGE - VALUE OF DYNAMIC CONTRAST-ENHANCED CT AMERICAN JOURNAL OF ROENTGENOLOGY Jeffrey, R. B., Cardoza, J. D., Olcott, E. W. 1991; 156 (4): 725-729

    Abstract

    Contrast-enhanced dynamic CT was used prospectively to diagnose and locate the site of active arterial intraabdominal hemorrhage in 18 patients. Active arterial extravasation was confirmed by angiography in five patients and by immediate surgery in nine. Two patients not undergoing surgery or angiography required multiple blood transfusions to correct rapidly falling hematocrit due to a coagulopathy. One patient died of hypovolemic shock, and autopsy confirmed a large acute retroperitoneal hematoma. Another patient with a splenic laceration and massive hemoperitoneum on CT had no active bleeding at the time of surgery, which was delayed 1 hr from the time of the CT. All patients were clinically thought to be hemodynamically stable and had systolic blood pressures greater than 110 mm Hg at the time of CT. In seven patients, hypotension developed either during (two patients) or immediately after (five patients) CT scanning, necessitating either immediate surgery or angiographic embolization. Contrast-enhanced dynamic CT is valuable in the diagnosis and localization of active arterial intraabdominal hemorrhage. Identification of the anatomic site of this potentially life-threatening hemorrhage is critical in determining whether immediate laparotomy or angiographic embolization is the preferred method of treatment.

    View details for Web of Science ID A1991FC83000010

    View details for PubMedID 2003435

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