Bio

Academic Appointments

Administrative Appointments

  • Chief, Nuclear Medicine Service, VA Palo Alto Health Care System (1998 - Present)

Honors & Awards

  • Presidential Distinguished Educator Award, Society of Nuclear Medicine (2010)
  • Distinguished Service Award, Western Regional Chapters Society of Nuclear Medicine (2006)
  • Taplin Lecturer, Western Regional Chapters Society of Nuclear Medicine (2005)
  • Commendation, Department of Veterans Affairs Palo Alto Health Care System (2004)

Professional Education

  • MD, University Southern California, Medicine (1979)

Community and International Work

  • Board of Directors

    Partnering Organization(s)

    American Board of Nuclear Medicine

    Location

    US

    Ongoing Project

    No

    Opportunities for Student Involvement

    No

  • President

    Partnering Organization(s)

    Society of Nuclear Medicine

    Populations Served

    Professional community

    Location

    International

    Ongoing Project

    No

    Opportunities for Student Involvement

    No

Contact

Research & Scholarship

Current Research and Scholarly Interests

Scintigraphic evaluation of coronary blood flow and myocardial function using single photon emission computed tomography (SPECT) and positron emission tomography (PET). Tumor imaging and characterization of pulmonary nodules with PET/CT.

Clinical Trials

  • Cervical Nodal Mets in Squamous Cell Carcinoma of H&N - MRI, FDG-PET, & Histopathologic Correlation Not Recruiting

    The purpose of this study is to determine the value of novel non-invasive medical imaging methods for detecting the spread of head and neck squamous cell carcinoma to the lymph nodes in the neck by comparing their results to findings at the time of surgery.

    Stanford is currently not accepting patients for this trial. For more information, please contact Quynh-Thu Le, (650) 498 - 6184.

    View full details

  • Correlation of PET-CT Studies With Serum Protein Analysis Not Recruiting

    To correlate serum proteomics patterns with PET/CT findings to improve cancer diagnosis, staging, prognosis, and therapy monitoring.

    Stanford is currently not accepting patients for this trial. For more information, please contact Erik Mittra, (650) 725 - 4711.

    View full details

Teaching

2017-18 Courses

Publications

All Publications

  • Variable activation of the DNA damage response pathways in patients undergoing single-photon emission computed tomography myocardial perfusion imaging. Circulation. Cardiovascular imaging Hee Lee, W., Nguyen, P., Hu, S., Liang, G., Ong, S., Han, L., Sanchez-Freire, V., Lee, A. S., Vasanawala, M., Segall, G., Wu, J. C. 2015; 8 (2): e002851

    Abstract

    Although single-photon emission computed tomography myocardial perfusion imaging (SPECT MPI) has improved the diagnosis and risk stratification of patients with suspected coronary artery disease, it remains a primary source of low-dose radiation exposure for cardiac patients. To determine the biological effects of low-dose radiation from SPECT MPI, we measured the activation of the DNA damage response pathways using quantitative flow cytometry and single-cell gene expression profiling.Blood samples were collected from patients before and after SPECT MPI (n=63). Overall, analysis of all recruited patients showed no marked differences in the phosphorylation of proteins (H2AX, protein 53, and ataxia telangiectasia mutated) after SPECT. The majority of patients also had either downregulated or unchanged expression in DNA damage response genes at both 24 and 48 hours post-SPECT. Interestingly, a small subset of patients with increased phosphorylation had significant upregulation of genes associated with DNA damage, whereas those with no changes in phosphorylation had significant downregulation or no difference, suggesting that some patients may potentially be more sensitive to low-dose radiation exposure.Our findings showed that SPECT MPI resulted in a variable activation of the DNA damage response pathways. Although only a small subset of patients had increased protein phosphorylation and elevated gene expression postimaging, continued care should be taken to reduce radiation exposure to both the patients and operators.

    View details for DOI 10.1161/CIRCIMAGING.114.002851

    View details for PubMedID 25609688

    View details for PubMedCentralID PMC4354894

  • Variable activation of the DNA damage response pathways in patients undergoing single-photon emission computed tomography myocardial perfusion imaging. Circulation. Cardiovascular imaging Lee, W. H., Nguyen, P., Hu, S., Liang, G., Ong, S., Han, L., Sanchez-Freire, V., Lee, A. S., Vasanawala, M., Segall, G., Wu, J. C. 2015; 8 (2)

    Abstract

    Although single-photon emission computed tomography myocardial perfusion imaging (SPECT MPI) has improved the diagnosis and risk stratification of patients with suspected coronary artery disease, it remains a primary source of low-dose radiation exposure for cardiac patients. To determine the biological effects of low-dose radiation from SPECT MPI, we measured the activation of the DNA damage response pathways using quantitative flow cytometry and single-cell gene expression profiling.Blood samples were collected from patients before and after SPECT MPI (n=63). Overall, analysis of all recruited patients showed no marked differences in the phosphorylation of proteins (H2AX, protein 53, and ataxia telangiectasia mutated) after SPECT. The majority of patients also had either downregulated or unchanged expression in DNA damage response genes at both 24 and 48 hours post-SPECT. Interestingly, a small subset of patients with increased phosphorylation had significant upregulation of genes associated with DNA damage, whereas those with no changes in phosphorylation had significant downregulation or no difference, suggesting that some patients may potentially be more sensitive to low-dose radiation exposure.Our findings showed that SPECT MPI resulted in a variable activation of the DNA damage response pathways. Although only a small subset of patients had increased protein phosphorylation and elevated gene expression postimaging, continued care should be taken to reduce radiation exposure to both the patients and operators.

    View details for DOI 10.1161/CIRCIMAGING.114.002851

    View details for PubMedID 25609688

    View details for PubMedCentralID PMC4354894

  • PET/CT with sodium 18F-fluoride for management of patients with prostate cancer. Journal of nuclear medicine : official publication, Society of Nuclear Medicine Segall, G. M. 2014; 55 (4): 531-533

    View details for DOI 10.2967/jnumed.113.133546

    View details for PubMedID 24591486

  • SNMMI/ABNM Joint Position Statement on Optimizing Training in Nuclear Medicine in the Era of Hybrid Imaging JOURNAL OF NUCLEAR MEDICINE Delbeke, D., Royal, H. D., Frey, K. A., Graham, M. M., Segall, G. M. 2012; 53 (9): 1490-1494

    View details for DOI 10.2967/jnumed.112.110346

    View details for Web of Science ID 000308685100034

    View details for PubMedID 22836344

  • Status of and Trends in Nuclear Medicine in the United States JOURNAL OF NUCLEAR MEDICINE Delbeke, D., Segall, G. M. 2011; 52: 24S-28S

    Abstract

    Nuclear medicine in the United States has grown because of advances in technology, including hybrid imaging, the introduction of new radiopharmaceuticals for diagnosis and therapy, and the development of molecular imaging based on the tracer principle, which is not based on radioisotopes. Continued growth of the field will require cost-effectiveness data and evidence that nuclear medicine procedures affect patients' outcomes. Nuclear medicine physicians and radiologists will need more training in anatomic and molecular imaging. New educational models are being developed to ensure that future physicians will be adequately prepared.

    View details for DOI 10.2967/jnumed.110.085688

    View details for Web of Science ID 000298162800005

    View details for PubMedID 22144551

  • Therapy Response Evaluation with Positron Emission Tomography-Computed Tomography SEMINARS IN ULTRASOUND CT AND MRI Segall, G. M. 2010; 31 (6): 490-495

    Abstract

    Positron emission tomography-computed tomography with F-18-fluorodeoxyglucose is widely used for evaluation of therapy response in patients with solid tumors but has not been as readily adopted in clinical trials because of the variability of acquisition and processing protocols and the absence of universal response criteria. Criteria proposed for clinical trials are difficult to apply in clinical practice, and gestalt impression is probably accurate in individual patients, especially with respect to the presence of progressive disease and complete response. Semiquantitative methods of determining tissue glucose metabolism, such as standard uptake value, can be a useful descriptor for levels of tissue glucose metabolism and changes in response to therapy if technical quality control measures are carefully maintained. The terms partial response, complete response, and progressive disease are best used in clinical trials in which the terms have specific meanings and precise definitions. In clinical practice, it may be better to use descriptive terminology agreed upon by imaging physicians and clinicians in their own practice.

    View details for DOI 10.1053/j.sult.2010.10.007

    View details for Web of Science ID 000285901400006

    View details for PubMedID 21147376

  • Session 3: Strategies to engage referring physicians and increase utilization of clinical molecular imaging JOURNAL OF NUCLEAR MEDICINE Segall, G. M. 2008; 49 (6): 52N-53N

    View details for Web of Science ID 000256491000015

    View details for PubMedID 18511827

  • A new paradigm to increase utilization of PET/CT JOURNAL OF NUCLEAR MEDICINE Segall, G. M. 2008; 49 (6): 53N-56N

    View details for Web of Science ID 000256491000016

    View details for PubMedID 18511828

  • A comparison of the diagnostic accuracy of F-18-FDG PET and CT in the characterization of solitary pulmonary nodules JOURNAL OF NUCLEAR MEDICINE Fletcher, J. W., Kymes, S. M., Gould, M., Alazraki, N., Coleman, R. E., Lowe, V. J., Marn, C., Segall, G., Thet, L. A., Lee, K. 2008; 49 (2): 179-185

    Abstract

    CT and PET are widely used to characterize solitary pulmonary nodules (SPNs). However, most CT accuracy studies have been performed with outdated technology and methods, and previous PET studies have been limited by small sample sizes and incomplete masking. Our objective was to compare CT and PET accuracy in veterans with SPN.Between January 1999 and June 2001, we recruited 532 participants with SPNs newly diagnosed on radiography and untreated. The SPNs were 7-30 mm. All patients underwent (18)F-FDG PET and CT. A masked panel of 3 PET and 3 CT experts rated the studies on a 5-point scale. SPN tissue diagnosis or 2-y follow-up established the final diagnosis.A definitive diagnosis was established for 344 participants. The prevalence of malignancy was 53%. The average size was 16 mm. Likelihood ratios (LRs) for PET and CT results for combined ratings of either definitely benign (33% and 9% of patients, respectively) or probably benign (27% and 12%) were 0.10 and 0.11, respectively. LRs for PET and CT results for combined ratings of indeterminate (1% and 25%), probably malignant (21% and 39%), or definitely malignant (35% and 15%) were 5.18 and 1.61, respectively. Area under the receiver operating characteristic curve was 0.93 (95% confidence interval, 0.90-0.95) for PET and 0.82 (95% confidence interval, 0.77-0.86) for CT (P < 0.0001 for the difference). PET inter- and intraobserver reliability was superior to CT.Definitely and probably benign results on PET and CT strongly predict benign SPN. However, such results were 3 times more common with PET. Definitely malignant results on PET were much more predictive of malignancy than were these results on CT. A malignant final diagnosis was approximately 10 times more likely than a benign final diagnosis in participants with PET results rated definitely malignant.

    View details for DOI 10.2967/jnumed.107.044990

    View details for Web of Science ID 000252866300023

    View details for PubMedID 18199626

  • Concurrent metabolic and osseous metastatic disease on a Tc99m-MDP bone scan EUROPEAN JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING Mittra, E., Segall, G. 2007; 34 (12): 2150-2150

    View details for DOI 10.1007/s00259-007-0535-x

    View details for Web of Science ID 000251370400034

    View details for PubMedID 17874099

  • A case of three synchronous primary tumors demonstrated by F-18FDG PET CLINICAL NUCLEAR MEDICINE Mittra, E., Vasanawala, M., Niederkohr, R., Rodriguez, C., Segall, G. 2007; 32 (8): 666-667

    Abstract

    We present an F-18 FDG PET scan which demonstrates 3 synchronous primary malignancies. The patient is a 61-year-old man who presented with weight loss and dysphagia. He was initially diagnosed with squamous cell carcinoma of the midesophagus, and was then found to have an adenocarcinoma in the right lung. A staging PET scan additionally showed increased left tonsillar uptake. Subsequent biopsy confirmed squamous cell carcinoma of the left tonsil. The demonstration of 3 synchronous primaries by PET is probably rare.

    View details for Web of Science ID 000248382000022

    View details for PubMedID 17667450

  • F-18 FDG PET visualization of urinary leak after nephrostomy tube removal CLINICAL NUCLEAR MEDICINE Iagaru, A., Gamie, S., Segall, G. 2007; 32 (2): 168-169

    View details for Web of Science ID 000243782800025

    View details for PubMedID 17242582

  • F-18FDG PET imaging of urinary bladder oat cell carcinoma with widespread osseous metastases CLINICAL NUCLEAR MEDICINE Iagaru, A., Gamie, S., Segall, G. 2006; 31 (8): 476-478

    View details for Web of Science ID 000241026700010

    View details for PubMedID 16855436

  • F-18FDG PET evaluation of bronchial plasmacytoma with CT and MRI correlation CLINICAL NUCLEAR MEDICINE Iagaru, A., Mari, C., Segall, G. 2006; 31 (5): 279-280

    View details for Web of Science ID 000237077700009

    View details for PubMedID 16622337

  • Oral administration of F-18FDG to evaluate a single pulmonary nodule by positron emission tomography in a patient with poor intravenous access CLINICAL NUCLEAR MEDICINE Franc, B., Carlisle, M. R., Segall, G. 2003; 28 (7): 541-544

    Abstract

    F-18 fluorodeoxyglucose (FDG) is typically administered intravenously for positron emission tomography. The authors present a case of oral administration of FDG for evaluation of a pulmonary nodule and review the limited literature on this subject. Oral administration of FDG is a useful alternative to intravenous administration in patients with difficult intravenous access when the alimentary tract is not involved in the clinical diagnosis.

    View details for Web of Science ID 000183782800001

    View details for PubMedID 12819404

  • Positron emission tomography of the thyroid, with an emphasis on thyroid cancer NUCLEAR MEDICINE COMMUNICATIONS McDougall, I. R., Davidson, J., Segall, G. M. 2001; 22 (5): 485-492

    Abstract

    The role of Positron Emission Tomography (PET) using 18F-fluorodeoxyglucose (FDG) in the management of thyroid cancer is discussed. It is important to ensure that patients are relaxed because uptake of FDG in tense or active muscles in the neck and larynx can be misinterpreted as metastases. The major role for PET is in patients where the stage of disease is uncertain, usually the result of discordant negative 131I scan and a positive serum thyroglobulin (Tg) values. PET identifies the source of Tg production in 50-80% of patients. PET scan can be negative in well differentiated cancers which retain the ability to trap iodine. This can result in a 'flip/flop', with negative PET, positive radio-iodine scan, or positive PET, negative radioiodine scan. PET is also valuable in identifying the source of calcitonin production in patients with medullary thyroid cancer. When focal uptake is seen in the thyroid of patients who are scanned for non thyroidal reasons, the likelihood of primary thyroid cancer is high. In contrast diffuse uptake of FDG in the thyroid is usually the result of auto-immune thyroid disorders.

    View details for Web of Science ID 000168832200004

    View details for PubMedID 11388568

  • FDG PET imaging in patients with lymphoma: A clinical perspective - Invited commentary JOURNAL OF NUCLEAR MEDICINE Segall, G. M. 2001; 42 (4): 609-610

    View details for Web of Science ID 000168000500017

    View details for PubMedID 11337550

  • Fluorodeoxyglucose positron emission tomography studies in diagnosis and staging of clinically organ-confined prostate cancer UROLOGY Liu, I. J., Zafar, M. B., Lai, Y. H., Segall, G. M., Terris, M. K. 2001; 57 (1): 108-111

    Abstract

    To determine the value of 18-fluoro-2-deoxyglucose (FDG) positron emission tomography (PET) studies in the evaluation of patients with organ-confined prostate cancer. This imaging method has previously found little usefulness in localized prostate tumors because of excretion of the isotope into the urine, masking any lower urinary tract lesions. We evaluated this imaging modality using hydration, furosemide, and bladder emptying before the procedure to evacuate the nonspecific isotope in the urine.FDG PET scans were performed on 24 patients diagnosed with clinically organ-confined prostate cancer. No patient had received any prior treatments for the cancer. FDG PET scans were performed 1 hour after injection of 15 mCi of F-18 deoxyglucose. Patients were scanned from the base of the skull through the inguinal region (including the pelvis). Additional signal attenuation-corrected images of the inguinal region were acquired 30 minutes after intravenous injection of 40 mg of furosemide. The final diagnosis was made by histologic examination, correlative imaging studies, and/or clinical follow-up.FDG PET studies were negative in 23 of the 24 organ-confined prostate cancers and the study was only faintly positive in 1 tumor (4.0% sensitivity).FDG PET is not a useful test in the evaluation of clinically organ-confined prostate cancer.

    View details for Web of Science ID 000166663000021

    View details for PubMedID 11164153

  • PET in differentiation of recurrent brain tumor from radiation injury JOURNAL OF NUCLEAR MEDICINE Langleben, D. D., Segall, G. M. 2000; 41 (11): 1861-1867

    Abstract

    The annual incidence of primary intracranial tumors is 7 to 19 cases per 100,000 people. The general approach to the treatment of brain neoplasms is surgical resection of solitary lesions or limited disease, followed by radiation therapy with or without chemotherapy. Multiple metastatic lesions are usually treated with whole-brain radiation. Radiation injury occurs in 5% to 37% of cases and can be difficult to differentiate from residual or recurrent malignancy by MRI. PET has been used to differentiate radiation injury from malignancy on the basis of differences in glucose uptake. Recent studies have reported the sensitivity and specificity of PET to be 81% to 86% and 40% to 94%, respectively. This article reviews the classification of primary brain tumors, the histologic changes associated with radiation injury, and the diagnostic and prognostic information provided by PET.

    View details for Web of Science ID 000165204600018

    View details for PubMedID 11079496

  • 9:45-10:00. Positron Emission Tomography (PET) is Superior to Computerized Tomography (CT) for Metastatic Staging in Melanoma Patients. Clinical positron imaging : official journal of the Institute for Clinical P.E.T Swetter, Carroll, Johnson, SEGALL 2000; 3 (4): 154-?

    Abstract

    PET provides diagnostic information currently not available with traditional imaging. Retrospective analysis was performed of 104 patients with primary or recurrent melanoma who underwent PET for staging to determine sensitivity/specificity compared to body CT. 157 PET and 70 CT scans were analyzed with a mean follow up of 26 months. Metastatic events were confirmed with positive histology (73%) or documented disease progression.PET demonstrated 86% sensitivity and 97% specificity in 41 patients with metastasis. CT showed 57% sensitivity and 70% specificity in 30 patients with metastasis. Exclusion of areas not evaluated on CT (head, neck/supraclavicular, and extremities) increased CT sensitivity to 68%. Fifty-three patients underwent 67 consecutive CT and PET scans that detected 132 metastases in 30 individuals. PET detected a greater percentage of metastases (83%) compared to CT (56%), and specifically, in the soft tissue, neck, peripheral/mediastinal/intraabdominal lymph nodes, and small bowel. PET detected 100% of mediastinal metastasis while CT detected only 67%. Surprisingly, PET detected 84% of lung parenchymal metastasis compared to 72% with CT.PET is more sensitive and specific than CT for detection of melanoma metastasis and should be considered the primary staging study upon suspicion of recurrent disease. PET shows greater ability to detect soft tissue, small bowel, and lymph node metastasis that do not meet criteria designated as abnormal by CT. Likewise, CT does not routinely evaluate the supraclavicular area, neck, or upper/lower extremities. However, even when these sites are excluded from comparative analysis, PET is superior to CT in detecting melanoma metastasis.

    View details for PubMedID 11150757

  • Comparison of FDG-PET and Bone Scans for Detecting Skeletal Metastases in Patients with Non-small Cell Lung Cancer. Clinical positron imaging : official journal of the Institute for Clinical P.E.T Durski, J. M., Srinivas, S., Segall, G. 2000; 3 (3): 97?105

    Abstract

    Purpose: Positron Emission Tomography (PET) with F18-fluorodeoxyglucose has been proven useful for staging non-small cell lung cancer. Bone scans are frequently performed for suspected skeletal metastases. The purpose of this study was to evaluate if bone scans compared to PET scans provide additional information that changes the stage of disease.Procedures: Nineteen patients with non-small cell lung cancer had PET and bone scans done for staging of the malignancy. The results of both studies were compared.Results: Bone and PET scans agreed on the presence or absence of skeletal metastases in all nineteen patients. The addition of a bone scan to a PET scan did not change the stage of the disease or the management in any of the patients. Bone scans allowed for more precise localization of the lesions in some patients.Conclusions: Bone scans do not change the stage of disease when performed in addition to PET scans, but provide more precise localization of skeletal abnormalities.

    View details for PubMedID 11008099

  • The effect of fluorine-18 fluorodeoxyglucose positron emission tomography on the management of cutaneous malignant melanoma CLINICAL NUCLEAR MEDICINE Jadvar, H., Johnson, D. L., Segall, G. M. 2000; 25 (1): 48-51

    Abstract

    To assess the effect of positron emission tomography (PET) with fluorine-18 fluorodeoxyglucose (FDG) on the treatment of patients with cutaneous malignant melanoma.We retrospectively reviewed the medical records of 38 patients with newly diagnosed (n = 25) and recurrent (n = 13) cutaneous melanoma who were referred for evaluation with FDG PET imaging at our institution. We compared the PET findings with computed tomography (CT), which was available in 21 (55%) patients, and tabulated the changes in the diagnostic evaluation and therapeutic management that were prompted by PET during a follow-up period of 10 to 36 months.Compared with PET, the extent of disease was underestimated by CT in 5 (13%) patients. Planned surgical resection of metastases was canceled in two of these patients. In another patient, surveillance PET detected an unsuspected hypermetabolic abdominal mass that was noted on a subsequent CT to arise from the small bowel. The mass was found to be jejunal metastatic melanoma at the time of resection. Overall, PET influenced surgical management in 3 (8%) patients, but it did not affect the wait-and-watch strategy or decision to initiate immunotherapy in the others.FDG PET contributes important information not provided by CT and has a substantial effect on the clinical management of patients with malignant melanoma.

    View details for Web of Science ID 000084584100011

    View details for PubMedID 10634531

  • Effect of atropine and sincalide on the intestinal uptake of F-18 fluorodeoxyglucose CLINICAL NUCLEAR MEDICINE Jadvar, H., Schambye, R. B., Segall, G. M. 1999; 24 (12): 965-967

    Abstract

    Variable diffuse intestinal uptake of F-18 fluorodeoxyglucose (FDG) is commonly seen in patients undergoing positron emission tomography (PET) imaging. Diffuse high uptake can obscure a lesion, whereas occasional high focal uptake can mimic a lesion. The cause of intestinal FDG uptake and the parameters that influence the level of uptake are unknown.We hypothesized that intestinal FDG uptake may result from smooth muscle peristalsis. We tested our hypothesis by comparing FDG uptake at baseline and after administration of two drugs (atropine and sincalide) that are known to affect intestinal motility. We performed FDG PET scans in random order in five healthy male volunteers without medication, after intramuscular administration of atropine, and after intravenous administration of sincalide.Qualitative comparison of the images before and after both medications did not show any significant difference in the level of intestinal FDG uptake.We conclude that intestinal FDG uptake is probably not caused by peristalsis. Mucosal uptake may be an alternative explanation.

    View details for Web of Science ID 000083936200012

    View details for PubMedID 10595478

  • Physiologic Source of Intestinal FDG Uptake. Effect of Atropine and Sincalide. Clinical positron imaging : official journal of the Institute for Clinical P.E.T Jadvar, H., Schambye, R. B., Segall, G. M. 1999; 2 (6): 318-?

    View details for PubMedID 14516615

  • A mathematical model for the distribution of fluorodeoxyglucose in humans JOURNAL OF NUCLEAR MEDICINE Hays, M. T., Segall, G. M. 1999; 40 (8): 1358-1366

    Abstract

    The goals of this study were to define the total body distribution kinetics of 18F-fluorodeoxyglucose (FDG), to contribute to its radiation dosimetry and to define a suitable proxy for arterial cannulation in human FDG studies.Time-activity FDG heart, lung, liver and blood data from paired fasting and glucose-loaded sessions in five adult human volunteers, together with published brain parameters, were incorporated into a multicompartmental model for whole-body FDG kinetics. Tau values were calculated from this model. We also compared the usefulness of activity in the left ventricle (LV), right ventricle (RV), left lung and right lung as proxy for arterial blood FDG sampling.No systematic difference was found in model parameters between the fasting and glucose-fed sessions, even for the parameter for transfer of FDG into the myocardium. Myocardial PET data fitted well to a model in which there is very rapid exchange indistinguishable from blood kinetics and transfer into an intracellular "sink." The lung data fitted to a simple sink representing the lung cells. The liver data required an additional intermediate exchange compartment between the plasma and a hepatic sink. In terms of total body distribution kinetics, unmeasured organs and tissues (probably the skeletal muscle and gut) become increasingly important with time and account for a mean of 76% of the decay-corrected FDG activity at infinity. Right lung activity, corrected to venous blood, represents the whole arterial blood curve better than the LV or RV. The tau values for radiation dosimetry of FDG in the heart, lungs, liver and bladder calculated from our model do not differ significantly from published results using other methods. Bladder tau decreased with voiding frequency and was markedly decreased with early voiding.Glucose loading state is not a good predictor of myocardial FDG uptake. The majority of FDG distribution at 90 min is in tissues other than the blood, brain, heart and liver. Bladder radiation will be much reduced if the patient voids early after FDG administration. Summed large volume right lung activity, normalized to venous blood activity, is a good proxy for arterial blood FDG sampling. The model presented may be expanded to include other FDG kinetics as studies become available.

    View details for Web of Science ID 000081902300020

    View details for PubMedID 10450689

  • Evaluation of suspected recurrent papillary thyroid carcinoma with [F-18]fluorodeoxyglucose positron emission tomography NUCLEAR MEDICINE COMMUNICATIONS Jadvar, H., McDougall, I. R., Segall, G. M. 1998; 19 (6): 547-554

    Abstract

    We evaluated 10 patients with suspected recurrent papillary thyroid cancer using [18F]fluorodeoxyglucose positron emission tomography (FDG PET). Prior therapy included total (n = 8) or subtotal (n = 2) thyroidectomy, radiation therapy (n = 2) and radioiodine ablation (n = 2). All patients had an 131I scan and one or more of the following imaging studies: 99Tcm-sestamibi scan. 111In-octreotide scan, sonography (US), computed tomography (CT) and magnetic resonance imaging (MRI). Both the PET and 131I scans were negative in four patients. The PET and 131I scan results were discordant in six patients. Of the six discordant cases, five had true-positive PET scans and false-negative 131I studies. Three of these patients underwent neck lymph node dissection that showed positive histology for metastatic papillary carcinoma. Another patient had fine-needle aspiration (FNA) of a parapharyngeal mass that was also positive for papillary carcinoma. One patient was treated with radiation to the thyroid surgical bed based on an elevated serum thyroglobulin and a positive PET finding. Tumour response with a decrease in the size of the lesion was documented by a follow-up MRI scan. The remaining patient had a presumed false-positive PET scan, since a difficult hypocellular FNA of a small palpable lymph node was negative for tumour. We conclude that FDG PET is useful in the evaluation of patients with suspected recurrent papillary thyroid cancer when the 131I scan is negative.

    View details for Web of Science ID 000074566100005

    View details for PubMedID 10234658

  • Hot water swallows improve symptoms and accelerate esophageal clearance in esophageal motility disorders JOURNAL OF CLINICAL GASTROENTEROLOGY Triadafilopoulos, G., Tsang, H. P., Segall, G. M. 1998; 26 (4): 239-244

    Abstract

    Cold liquid ingestion may precipitate episodes of dysphagia and chest pain in patients with spastic esophageal motility disorders. The effect of hot liquids on esophageal symptoms, esophageal peristalsis, and clearance and any potential therapeutic benefit in such patients has not been examined. Using esophageal scintigraphy and manometry, we have investigated the effects of hot water swallows on dysphagia, chest pain, and esophageal motility and clearance in patients with esophageal motility disorders. We studied 48 men and women with intermittent dysphagia to both solids and liquids, chest pain, and/or regurgitation. All patients underwent upper endoscopy, barium swallow, and esophageal manometry using standard techniques. Esophageal scintigraphy assessed esophageal transit time (ETT) and retrograde intraesophageal movement of bolus at baseline (22 degrees C) and after hot (60 degrees C) water swallows. Esophageal manometry assessed the amplitude and duration of esophageal contractions in response to baseline and hot water swallows. Patients were followed clinically for as long as 6 months to assess symptomatic response. We found that baseline esophageal scintigraphy revealed a mean ETT of 48.5 seconds; after hot water swallow, mean ETT was 27.8 seconds (p < 0.001). The number of secondary peaks at baseline was 3.5; after hot water swallow, it was 2.1 (p < 0.001). Baseline esophageal manometry showed a mean esophageal body contraction amplitude of 188 mm Hg (mean duration, 11.8 seconds) in response to wet swallows and 125 mm Hg (mean duration, 5.7 seconds) with hot water swallows (p < 0.001). Clinically, 28 (58%) of 48 patients noted significant (>50%) improvement of their symptoms and have been ingesting hot water or other hot liquids regularly with their meals. We conclude that hot water accelerates esophageal clearance, decreases the amplitude and duration of esophageal body contractions, and improves symptoms in patients with esophageal motility disorders. Because of its safety and simplicity, it may have an important role in the management of these chronic conditions.

    View details for Web of Science ID 000074134700003

    View details for PubMedID 9649001

  • Effect of radionuclide renograms on treatment of patients with spinal cord injuries AMERICAN JOURNAL OF ROENTGENOLOGY PHILLIPS, J. R., Jadvar, H., Sullivan, G., Lin, V. W., Segall, G. M. 1997; 169 (4): 1045-1047

    Abstract

    Urinary tract problems stemming from neurologic dysfunction are a major cause of morbidity in patients with spinal cord injury. Radionuclide renograms have been used to monitor renal function in these patients. However, the effect of renographic results on the treatment of patients has not been studied. A retrospective study was done to determine the effect of radionuclide renography on the diagnostic evaluation and therapeutic treatment of patients with spinal cord injury.The records of 199 patients with spinal cord injuries were reviewed. A decline in effective renal plasma flow of 20% or more, a low effective renal plasma flow for age, and abnormal tracer time-activity curves were correlated with diagnostic procedures and therapeutic interventions. Diagnostic procedures included renal sonography, CT, excretory urography, and urodynamics. Therapeutic interventions included changes in medication, changes in bladder management, and surgery.Patients with abnormal findings on renograms underwent more diagnostic procedures and therapeutic interventions. A significant correlation was found between abnormal tracer time-activity curves and use of excretory urography. A decline in effective renal plasma flow was the best predictor of therapeutic intervention.Radionuclide renograms influence the diagnostic evaluation and therapeutic treatment of patients with spinal cord injury.

    View details for Web of Science ID A1997XW98100025

    View details for PubMedID 9308462

  • False-negative fluorine-18-FDG PET in metastatic carcinoid JOURNAL OF NUCLEAR MEDICINE Jadvar, H., Segall, G. M. 1997; 38 (9): 1382-1383

    Abstract

    Carcinoid tumors have high numbers of somatostatin receptors that allow scintigraphic imaging with the radiolabeled somatostatin analog octreotide. Experience, however, with PET using 2-[18F]fluoro-2-deoxy-D-glucose (18FDG) in carcinoid is very limited. In two prior studies which investigated the utility of 18FDG-PET in cancer detection, three patients with small, solitary, indolent carcinoid tumors had false-negative results. We report a case where 18FDG-PET imaging was false-negative in a patient with known metastatic carcinoid and a positive octreotide scan.

    View details for Web of Science ID A1997XV76600020

    View details for PubMedID 9293792

  • Fast acquisition of myocardial SPECT images with Tc-99m sestamibi for the diagnosis of coronary artery disease JOURNAL OF NUCLEAR CARDIOLOGY Segall, G. M., Stepp, C., Kadkade, P. P., Dae, M. W., Botvinick, E. H. 1997; 4 (5): 358-363

    Abstract

    Shortening the acquisition time for myocardial single-photon emission computed tomographic (SPECT) imaging increases patient comfort and laboratory throughput. The purpose of this study was to compare the diagnostic accuracy for coronary artery disease detection of myocardial SPECT images acquired in 5 to 10 minutes versus 25 minutes using Tc-99m methoxyisobutylisonitrile (Tc-99m sestamibi) and a single-head gamma camera.Forty-one subjects had a standard 1-day rest/stress Tc-99m sestamibi myocardial SPECT study. Two sets of rest and stress images were acquired on the same day for each subject. One set of images was acquired with a 5- to 10-minute fast acquisition protocol; the second set of images was acquired with a 25-minute standard protocol. The accuracies of the fast and standard protocols for identifying individuals with and without coronary artery disease were equivalent. Accuracy was 76% for the fast protocol and 73% for the standard protocol in individuals with at least one coronary stenosis > or = 70%. The accuracies of the two protocols for identifying individual coronary arteries with stenoses > or = 70% also were equivalent. Accuracy was 77% for the fast protocol and 74% for the standard protocol.SPECT myocardial images may be acquired in as little as 5 to 10 minutes using Tc-99m sestamibi and a 1-day rest/stress protocol. Accuracy is equivalent to that attained in studies with longer imaging times.

    View details for Web of Science ID A1997YE75000003

    View details for PubMedID 9362011

  • Psychological stress and myocardial perfusion in coronary disease patients and healthy controls JOURNAL OF PSYCHOSOMATIC RESEARCH BENIGHT, C. C., Segall, G. M., Ford, M. E., Goetsch, V. L., Hays, M. T., Taylor, C. B. 1997; 42 (2): 137-144

    Abstract

    This study examined the effect of two different psychological stressors on regional cardiac perfusion in six men with coronary heart disease (CHD) and nine healthy controls. Subjects recalled an anger experience and an anger plus helpless (i.e., Desperation Recall Task) experience during positron emission tomography (PET). Emotional reactivity, blood pressure, and heart rate were also assessed. Experimental manipulations generated significant emotional and cardiovascular reactivity. Cardiac perfusion to diseased myocardial segments failed to show any significant differences between CHD patients' diseased segments and controls' healthy segments for the Anger Recall task or the Desperation Recall Task. Results failed to confirm previous findings of coronary artery constriction while reliving an angry experience, yet are consistent with other studies utilizing mental arithmetic. Vasoactive medication use, sample size, and perfusion variability may have contributed to these findings.

    View details for Web of Science ID A1997WK44200003

    View details for PubMedID 9076641

  • Low probability lung scan in a patient at high risk for pulmonary embolism JOURNAL OF NUCLEAR MEDICINE Kwok, C. G., SKIBO, L. K., Segall, G. M. 1996; 37 (1): 165-170

    View details for Web of Science ID A1996TP05200036

    View details for PubMedID 8543989

  • VARIABILITY OF NORMAL CORONARY ANATOMY - IMPLICATIONS FOR THE INTERPRETATION OF THALLIUM-SPECT MYOCARDIAL PERFUSION IMAGES IN SINGLE-VESSEL DISEASE JOURNAL OF NUCLEAR MEDICINE Segall, G. M., Atwood, J. E., Botvinick, E. H., Dae, M. W., Lucas, J. R. 1995; 36 (6): 944-951

    Abstract

    Standard criteria for assigning perfusion defects to a specific vascular territory often result in mistaken identification of the affected coronary artery due to the normal variability of coronary anatomy. A retrospective study was performed to determine the frequency of this type of error and to identify the most common perfusion patterns associated with specific coronary lesions.Records were reviewed of all patients with single-vessel coronary artery disease (CAD) who had exercise or dipyridamole thallium SPECT myocardial perfusion studies since 1987. Patients with coronary artery bypass grafts and an interval between the two studies greater than 6 wk or interval change in medical status were excluded. Ninety-three studies were available for review. The size, severity and location of all perfusion defects were noted by three observers who had no knowledge of the angiographic data. Significant CAD was defined as luminal diameter stenosis greater than 50%.The diseased vessel was correctly identified in 85% of positive studies. Thallium SPECT, however, mistakenly predicted additional vessel involvement in 29% of those studies. Another 15% correctly predicted single-vessel disease but identified the wrong artery. Using standard criteria, thallium SPECT correctly predicted the arteriogram findings in only 56% of studies. Most of these findings could be correlated with variations in individual coronary anatomy.The accurate localization of coronary stenoses by thallium SPECT imaging requires close correlation with arteriography owing to the significant variability in normal coronary anatomy.

    View details for Web of Science ID A1995RB81600015

    View details for PubMedID 7769450

  • IN-VITRO EVALUATION OF WHITE BLOOD-CELL LABELING WITH 99TCM RADIOPHARMACEUTICALS NUCLEAR MEDICINE COMMUNICATIONS Segall, G. M., Lang, E. V., CHAOVAPONG, W. 1994; 15 (10): 845-849

    Abstract

    Several commercially available 99Tcm radiopharmaceuticals were tested as possible white blood cell labelling agents. Labelling efficiency, labelling stability and white blood cell adherence were measured in vitro. White blood cells were not successfully labelled with mebrofenin, disofenin, gluceptate or dimercaptosuccinic acid but were successfully labelled with exametazime, albumin colloid, sulphur colloid, sestamibi and teboroxime. Exametazime had the highest mean labelling efficiency of 79%. Labelling efficiency was 5-14% with albumin colloid, sulphur colloid, sestamibi and teboroxime. Labelling stability was high (> 95% at 4 h and > 80% at 24 h) for all agents except sestamibi (52% at 4 h and 5% at 24h). Exametazime did not alter white blood cell adherence. Albumin colloid, sestamibi and teboroxime decreased adherence and sulphur colloid increased adherence. Exametazime appears to be the best agent for labelling white blood cells. Teboroxime, however, is a new agent for labelling white blood cells which deserves further investigation.

    View details for Web of Science ID A1994PK95100010

    View details for PubMedID 7838449

  • REST EXERCISE THALLIUM MYOCARDIAL PERFUSION IMAGING - A NEW AND RAPID TECHNIQUE TO EVALUATE CORONARY-ARTERY DISEASE NUCLEAR MEDICINE COMMUNICATIONS Segall, G. M., ZIPKIN, R. E. 1993; 14 (6): 465-470

    Abstract

    Twenty-six patients underwent conventional exercise/4-h redistribution thallium myocardial perfusion imaging as well as rest/exercise imaging on different days. For the rest/exercise study, patients were imaged 10 min after receiving 1 mCi thallium at rest. The resting study was immediately followed by symptom-limited treadmill exercise. Patients were injected with 2 mCi thallium at peak exercise and imaged 10 min later. The entire rest/exercise study was completed in 2 h. There was a high degree of correlation between the two studies. Of the 130 segments analysed, 84 were normal and 46 were abnormal by exercise/redistribution imaging whereas 88 were normal and 42 were abnormal by rest/exercise imaging. Among the 14 patients who had coronary arteriography, both exercise/redistribution and rest/exercise imaging correctly identified 23/35 segments as abnormal (sensitivity [pi003] 66%) and 34/35 segments as normal (specificity = 97%). Furthermore, abnormal segments were more likely to be reversible on the rest/exercise study. The results suggest that the accuracy of rest/exercise thallium imaging is equal to conventional exercise/redistribution imaging in the evaluation of coronary artery disease. The significant time economy and possible improvement in assessing myocardial viability are important potential advantages of this new technique.

    View details for Web of Science ID A1993LF94700009

    View details for PubMedID 8321485

  • QUALITY ASSURANCE OF WHITE BLOOD-CELL LABELING WITH A TEST BASED ON ADHERENCE JOURNAL OF NUCLEAR MEDICINE Lang, E. V., Nigh, E., EUBANKS, R. S., Lang, J. H., Segall, G. M. 1993; 34 (2): 345-348

    Abstract

    A new quality control assay was developed based on the premise that proper radioactive labeling should not affect the adherence characteristics of white blood cells to nylon fibers. Heparinized whole blood with trace amounts of radioactively labeled white blood cells was passed over nylon fiber columns and eluted in eight fractions. Percent radioactive adherence (%RA) and percent white blood cell adherence (%WBCA) were determined for each fraction. Regression lines (%RA versus %WBCA) were calculated for 9 samples labeled properly with 111In-oxine and for 17 samples intentionally subjected to improper labeling. Properly labeled preparations had a median slope = 1.05 and an intercept = 1%. Improperly labeled preparations had significantly lower slopes and/or higher intercepts. By the use of +/- 2 s.d. ranges as indicators of proper labeling (slope of 0.71-1.74; intercept of -35%-37%), the test had 100% sensitivity and 94% specificity. We conclude that proper labeling with 111In-oxine preserves the adherence characteristics of white blood cells, that improper labeling may affect the binding strength of white blood cells (decrease in slope) and/or lead to formation of sticky cell subgroups (increased intercept) and that the quality control assay can objectively assess the impact of labeling on adherence.

    View details for Web of Science ID A1993KK92600034

    View details for PubMedID 8429359

  • FUNCTIONAL IMAGING OF PERIPHERAL VASCULAR-DISEASE - A COMPARISON BETWEEN EXERCISE WHOLE-BODY THALLIUM PERFUSION IMAGING AND CONTRAST ARTERIOGRAPHY JOURNAL OF NUCLEAR MEDICINE Segall, G. M., Lang, E. V., LENNON, S. E., STEVICK, C. D. 1992; 33 (10): 1797-1800

    Abstract

    Whole-body thallium scintigraphy was used to study leg muscle perfusion in 12 healthy individuals and 31 patients with peripheral vascular disease. Subjects were scanned immediately after exercise and 4 hr later. Buttock, thigh and calf perfusion were measured in terms of fractional uptake relative to whole-body activity, percent change in fractional uptake over 4 hr and interextremity symmetry ratios. The results were compared to contrast arteriography on a region by region basis. The overall sensitivity and specificity of thallium scintigraphy were 80% and 73%, respectively. The results suggest that thallium scintigraphy may provide useful information about the hemodynamic significance of noncritical anatomic lesions.

    View details for Web of Science ID A1992JU52000017

    View details for PubMedID 1306653

  • EFFECTS OF ANGER ON LEFT-VENTRICULAR EJECTION FRACTION IN CORONARY-ARTERY DISEASE AMERICAN JOURNAL OF CARDIOLOGY Ironson, G., Taylor, C. B., BOLTWOOD, M., BARTZOKIS, T., Dennis, C., Chesney, M., Spitzer, S., Segall, G. M. 1992; 70 (3): 281-285

    Abstract

    This study examined the comparative potency of several psychological stressors and exercise in eliciting myocardial ischemia as measured by left ventricular (LV) ejection fraction (EF) changes using radionuclide ventriculography. Twenty-seven subjects underwent both exercise (bicycle) and psychological stressors (mental arithmetic, recall of an incident that elicited anger, giving a short speech defending oneself against a charge of shoplifting) during which EF, blood pressure, heart rate and ST segment were measured. Eighteen subjects had 1-vessel coronary artery disease (CAD), defined by greater than 50% diameter stenosis in 1 artery as assessed by arteriography. Nine subjects served as healthy control subjects. Anger recall reduced EF more than exercise and the other psychological stressors (overall F [3.51] = 2.87, p = .05). Respective changes in EF for the CAD patients were -5% during anger recall, +2% during exercise, 0% during mental arithmetic and 0% during the speech stressor. More patients with CAD had significant reduction in EF (greater than or equal to 7%) during anger (7 of 18) than during exercise (4 of 18). The difference in EF change between patients with CAD and healthy control subjects was significant for both anger (t25 = 2.23, p = 0.04) and exercise (t25 = 2.63, p = 0.01) stressors. In this group of patients with CAD, anger appeared to be a particularly potent psychological stressor.

    View details for Web of Science ID A1992JE54300003

    View details for PubMedID 1632389

  • EFFECT OF FLOW-RATE ON ADHERENCE OF UNLABELED AND IN-111 OXINE-LABELED LEUKOCYTES INVESTIGATIVE RADIOLOGY Lang, E. V., Lang, J. H., Segall, G. M. 1992; 27 (1): 50-54

    Abstract

    Uptake of radioactively labeled leukocytes has been observed in ischemic noninfected regions. Since this may be a flow-related phenomenon, the authors investigated the effect of flow rate on adherence of indium-111 oxine-labeled leukocytes with a model based on the elution patterns of radioactivity and granulocytes from nylon fiber columns. Relative radioactivity adherence (%RA) and relative granulocyte adherence (%GA) agreed closely, indicating that radioactivity retained by the columns is predominantly in the form of viable labeled granulocytes, and that labeled and unlabeled granulocytes have the same adherence characteristics. When other conditions were held constant, but passage speed was varied, %GA and %RA were related to the flow rate in an inverse linear fashion. Decrease in flow rate can lead to increased accumulation of leukocytes.

    View details for Web of Science ID A1992GX89400007

    View details for PubMedID 1733881

  • SAFETY OF DIPYRIDAMOLE-THALLIUM IMAGING IN HIGH-RISK PATIENTS WITH KNOWN OR SUSPECTED CORONARY-ARTERY DISEASE JOURNAL OF NUCLEAR MEDICINE PERPER, E. J., Segall, G. M. 1991; 32 (11): 2107-2114

    Abstract

    The effects of an oral dipyridamole suspension were studied in 400 consecutive patients to determine if certain subsets of patients were at greater risk of suffering major complications. Most patients (69%) experienced at least one side effect. Severe chest pain, severe hypotension, and severe dyspnea occurred in 9%, 2.5%, and 0.3% of patients respectively. Two patients were hospitalized for persistent chest pain but none suffered a myocardial infarction, malignant ventricular arrhythmia, or death. The test was found to be safe for patients over 70 yr old. Severe dyspnea was rare even among patients with lung disease who were withdrawn from theophylline prior to testing. Patients with three-vessel coronary artery disease were more likely to experience severe chest pain and those with significant left ventricular dysfunction were more likely to develop severe hypotension. In 99.5% of patients, side effects were promptly reversed by aminophylline. Dipyridamole-thallium imaging has an acceptable safety profile for a wide variety of patients, including those with severe coronary disease and/or left ventricular dysfunction.

    View details for Web of Science ID A1991GP12700023

    View details for PubMedID 1941146

  • EXERCISE WHOLE-BODY THALLIUM SCINTIGRAPHY IN THE DIAGNOSIS AND EVALUATION OF OCCLUSIVE ARTERIAL-DISEASE IN THE LEGS JOURNAL OF NUCLEAR MEDICINE Segall, G. M., LENNON, S. E., STEVICK, C. D. 1990; 31 (9): 1443-1449

    Abstract

    Whole-body thallium scintigraphy can be used to diagnose and evaluate occlusive arterial disease in patients with leg claudication. We performed exercise and redistribution scans in 36 healthy individuals and 17 patients with claudication. Regions of interest were drawn around the whole body, as well as each buttock, thigh, and calf. Counts in each region were expressed as a percentage of whole-body activity, as well as an interextremity activity ratio for each level. Significant differences due to gender and age were found. The sensitivity and specificity of the test in men was 94% and 71%, respectively, using the criterion of percentage regional uptake and 81% and 90%, respectively, using interextremity comparison. We conclude that exercise whole-body thallium imaging is a simple and accurate test for the evaluation of suspected occlusive arterial disease in the legs.

    View details for Web of Science ID A1990DX50300005

    View details for PubMedID 2118563

  • KINETICS OF LEUKOCYTE SEQUESTRATION IN THE LUNGS OF ACUTELY SEPTIC PRIMATES - A STUDY USING IN-111 LABELED AUTOLOGOUS LEUKOCYTES JOURNAL OF SURGICAL RESEARCH HANGEN, D. H., Segall, G. M., HARNEY, E. W., Stevens, J. H., McDougall, I. R., Raffin, T. A. 1990; 48 (3): 196-203

    Abstract

    To further clarify the role of leukocytes in the pathogenesis of ARDS, we studied the localization and kinetics of leukocyte migration using 111In-labeled autologous white cell scans (111In wbc scans) in four primates made acutely septic with infusions of Escherichia coli. Whole body images were obtained with a gamma camera and were acquired on computer every 15 min beginning immediately after the E. coli infusion. Simultaneous measurements of C5a and peripheral blood leukocyte count were also obtained. Within 5 min of initiating sepsis, three major events occurred: complement activation as measured by the production of C5a, a profound fall in peripheral leukocyte count, and a significant increase in the sequestration of leukocytes in the lungs. The pulmonary sequestration reached a peak at 15 min with a mean of 152% of baseline activity. This sequestration consisted of a population that was predominantly neutrophils. Damage to the pulmonary capillary endothelium was demonstrated by an increase in extravascular lung water. The results support a role for neutrophils and complement as mediators in the pathogenesis of ARDS.

    View details for Web of Science ID A1990CV60600003

    View details for PubMedID 2314092

  • SEQUENTIAL ASSESSMENT OF PULMONARY EPITHELIAL DIETHYLENE TRIAMINE PENTA-ACETATE CLEARANCE AND INTRAPULMONARY TRANSFERRIN ACCUMULATION DURING ESCHERICHIA-COLI PERITONITIS AMERICAN REVIEW OF RESPIRATORY DISEASE Ishizaka, A., Stephens, K. E., Segall, G. M., HATHERILL, J. R., McDougall, I. R., Wu, Z. H., Raffin, T. A. 1990; 141 (3): 631-639

    Abstract

    The individual roles of pulmonary capillary endothelial and alveolar epithelial permeability in the pathogenesis of the adult respiratory distress syndrome (ARDS) are unclear. We developed a method for the sequential assessment of pulmonary macromolecule accumulation and small solute clearance in vivo using a gamma camera. We measured the exponential clearance coefficient of 111In-labeled diethylene triamine penta-acetate (111In-DTPA) to assess airway clearance of small solutes. We also calculated the exponential equilibration coefficient of 111In-labeled transferrin (111In-TF) to assess intrapulmonary accumulation of transferrin. We determined these parameters in guinea pigs with Escherichia coli peritonitis and compared them with a saline-treated control group, oleic-acid-treated groups, and a group treated with low molecular weight dextran Ringer solution. The pulmonary DTPA clearance and the intrapulmonary transferrin accumulation were significantly increased in the peritonitis group (29.4 +/- 8.2 x 10(-3) min-1, p less than 0.02, and 15.1 +/- 3.1 x 10(-3) min-1, p less than 0.02) when compared with the control group (3.1 +/- 0.8 x 10(-3) min-1 and 4.5 +/- 0.5 x 10(-3) min-1). These changes developed within 5.5 h of the initial insult. Neither increased extravascular lung water nor elevated pulmonary artery and left atrial pressures were detected in the peritonitis group. The low molecular weight dextran Ringer group did not show a significant increase in the pulmonary DTPA clearance and the intrapulmonary transferrin accumulation.(ABSTRACT TRUNCATED AT 250 WORDS)

    View details for Web of Science ID A1990CT66700020

    View details for PubMedID 2178527

  • THE ROLE OF BONE-SCAN AND RADIOGRAPHY IN THE DIAGNOSTIC EVALUATION OF SUSPECTED PEDAL OSTEOMYELITIS CLINICAL NUCLEAR MEDICINE Segall, G. M., NINOMURCIA, M., Jacobs, T., Chang, K. 1989; 14 (4): 255-260

    Abstract

    The authors reviewed the three-phase bone scans and radiographs of 24 patients with suspected pedal osteomyelitis who also had histologic confirmation of the diagnosis. Twenty patients had a pedal ulcer, cellulitis, or necrosis. Sensitivity and specificity of bone scanning were 70% and 43% respectively. Sensitivity and specificity of radiography were 70% and 50% respectively. The non-invasive diagnosis of pedal osteomyelitis remains problematic due to the poor specificity of bone scans and radiographs.

    View details for Web of Science ID A1989U252100003

    View details for PubMedID 2706867

  • PRONE VERSUS SUPINE THALLIUM MYOCARDIAL SPECT - A METHOD TO DECREASE ARTIFACTUAL INFERIOR WALL DEFECTS JOURNAL OF NUCLEAR MEDICINE Segall, G. M., Davis, M. J. 1989; 30 (4): 548-555

    Abstract

    Artifactual inferior wall defects as a result of diaphragmatic attenuation of activity are a frequent source of error in thallium myocardial single photon emission computed tomography (SPECT) studies. Thirty-four patients and 11 clinically normal volunteers were studied prospectively to see if specificity of inferior wall defects for right coronary artery disease could be improved by scanning patients prone versus supine. All individuals were scanned both prone and supine, in random order, following symptom limited treadmill exercise. Images were acquired at 3 degrees steps, 25 sec per frame, in a 180 degrees elliptical orbit always beginning in the 45 degrees right anterior oblique position relative to the patient. Polar maps generated from the short axis slices were used to calculate the average regional activity. The prone studies showed consistently higher inferior wall activity compared to the supine studies on both the exercise (182 +/- 22 vs. 160 +/- 23, p less than or equal to 0.001) and 4-hr delay studies (183 +/- 20 vs. 175 +/- 21, p less than or equal to 0.001). Prone imaging resulted in a significantly higher specificity for RCA disease compared to supine imaging (90% vs. 66%, p less than 0.05) with an improvement in accuracy from 71% to 82%. Sensitivity, specificity, and accuracy for left anterior descending and left circumflex artery disease were not significantly affected by patient position during imaging. All patients having SPECT thallium myocardial perfusion studies should be imaged prone to minimize artifactual inferior wall defects and improve accuracy.

    View details for Web of Science ID A1989T939600019

    View details for PubMedID 2661750

  • VARIABILITY OF SERUM DRUG LEVEL FOLLOWING A SINGLE ORAL DOSE OF DIPYRIDAMOLE JOURNAL OF NUCLEAR MEDICINE Segall, G. M., Davis, M. J. 1988; 29 (10): 1662-1667

    Abstract

    Serum dipyridamole levels were measured in 27 patients undergoing planar thallium-201 myocardial perfusion scintigraphy after receiving a 300 mg oral dose. Mean serum dipyridamole level was 2.9 +/- 1.6 mcg/ml (range 0.2-5.7). No correlation was found between serum level and symptoms, heart rate or blood pressure response, peak heart to lung thallium activity ratio, peak heart to liver thallium activity ratio, or peak myocardial thallium washout. Serum level following a single oral dose of dipyridamole is unpredictable and patients with low drug levels cannot be easily identified at the time of study.

    View details for Web of Science ID A1988Q348500010

    View details for PubMedID 3171696

  • NONINVASIVE DETECTION OF HUMAN CARDIAC TRANSPLANT REJECTION WITH IN-111 ANTIMYOSIN (FAB) IMAGING CIRCULATION FRIST, W., Yasuda, T., Segall, G., Khaw, B. A., Strauss, H. W., Gold, H., STINSON, E., Oyer, P., Baldwin, J., Billingham, M., McDougall, I. R., Haber, E. 1987; 76 (5): 81-85

    View details for Web of Science ID A1987L004500015

  • Noninvasive detection of human cardiac transplant rejection with indium-111 antimyosin (Fab) imaging. Circulation FRIST, W., Yasuda, T., Segall, G., Khaw, B. A., Strauss, H. W., Gold, H., STINSON, E., Oyer, P., Baldwin, J., Billingham, M. 1987; 76 (5): V81-5

    Abstract

    Diagnosis of rejection after cardiac transplantation is currently made by right ventricular endomyocardial biopsy. To evaluate antimyosin imaging as a noninvasive means of detecting human cardiac rejection, the Fab fragment of murine monoclonal antimyosin antibodies was labeled with indium-111 and given intravenously to 18 patients (age 45 +/- 12 years) in 20 studies 7 days to 9 years after transplantation. Endomyocardial biopsy specimens were obtained at the time of each imaging study. Eight patients had positive scans confirmed by biopsy as rejection, and eight patients had negative scans and no evidence of rejection on biopsy. Discordance was observed in four studies, two with positive scans and no rejection on biopsy and two with negative scans and positive biopsy. The sensitivity, specificity, and overall accuracy of the technique were each 80%. Imaging with radiolabeled antimyosin antibody Fab fragments may be of value in the noninvasive identification of rejection in the cardiac transplant recipient.

    View details for PubMedID 3311460

  • ADHERENCE OF RADIOPHARMACEUTICALS AND LABELED CELLS TO INTRAVENOUS TUBING CLINICAL NUCLEAR MEDICINE Segall, G. M., Gurevich, N., McDougall, I. R. 1986; 11 (12): 830-833

    Abstract

    A survey of 67 nuclear medicine departments revealed no agreement on which radiolabeled agents could be injected through intravenous lines (IVs) and which required direct venipuncture. Labeled cells and several common radiopharmaceuticals were tested for adherence to intravenous tubing. Residual activity remaining in the tubing after an adequate flush was less than 1% of the injected dose in each case. Administration of radiolabeled agents through existing IVs is an acceptable alternative to direct venipuncture in many cases.

    View details for Web of Science ID A1986F214900006

    View details for PubMedID 3815981

  • DIAGNOSTIC-VALUE OF LUNG UPTAKE OF IN-111 OXINE-LABELED WHITE BLOOD-CELLS AMERICAN JOURNAL OF ROENTGENOLOGY Segall, G. M., McDougall, I. R. 1986; 147 (3): 601-606

    Abstract

    One hundred sixty-two white-blood-cell scans were retrospectively reviewed to determine the sensitivity and specificity of the test for pulmonary and pleural infection. All scans were performed 18-24 hr after injection of indium-111 oxine-labeled autologous or donor cells. Pulmonary activity was graded on a scale of 0-4: 0 = equal to soft tissue; 1 = greater than soft tissue but less than rib; 2 = equal or greater than rib but less than liver; 3 = equal or greater than liver but less than spleen; 4 = equal to spleen. Activity was also characterized as being focal or diffuse. The white-blood-cell scan findings were correlated with the clinical diagnosis on the basis of physical examination, laboratory results, chest radiographs, clinical course, and pathologic studies when available. As pulmonary activity increased from grade 1 to 4, sensitivity declined from 93% to 14% and specificity increased from 64% to 100%. The sensitivity and specificity of focal uptake were 31% and 89% vs 62% and 74% for diffuse pulmonary activity. Making a distinction between focal and diffuse activity did not improve the specificity of low grades of pulmonary activity. The white-blood-cell scan can be very sensitive or very specific for pulmonary or pleural infection, depending on the criteria selected for a positive scan.

    View details for Web of Science ID A1986D685000034

    View details for PubMedID 3090866

  • NONVISUALIZATION OF THE LIVER BY IN-111 OXINE LABELED LEUKOCYTES IN ALCOHOLIC LIVER-DISEASE CLINICAL NUCLEAR MEDICINE Segall, G. M., Goodwin, D. A. 1986; 11 (2): 79-81

    Abstract

    The liver was not visualized by In-111 WBC scan in a patient with alcoholic liver disease. The liver was visualized on repeat scan when liver function had improved.

    View details for Web of Science ID A1986AZG8600002

    View details for PubMedID 3095010

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