Dan Pavel

ICSS, PathFinder Brain SPECT, Director

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Address: Deerfield , Illinois, United States

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Fourier classification images in cardiac nuclear medicine

by Enrique Olea and Dan Pavel

IEEE Transactions on Medical Imaging, 1989

Abstruct-At present, the diagnosis of cardiac left ventricular regional wall motion abnormalities... more Abstruct-At present, the diagnosis of cardiac left ventricular regional wall motion abnormalities (RWMA) in nuclear medicine is aided mainly by the phase images and amplitude images. They picture the spatial distribution of the phase and of the amplitude of the first harmonics of pixel time activity curves, respectively. However, they do not utilize other information contained in the original radionuclide images, and they do not offer a direct diagnostic interpretation of the data. The proposed Fourier classification images (FCI) overcome these deficiencies. Their pixel intensities express directly the diagnostic class of RWMA. The FCI pixel intensities are functions of pixel coordinates, Fourier features of pixel time activity curves and their distribution parameters, and are not limited by the first harmonics model. The derivation of the pixel classifier includes normalization transforms of coordinates and activities, Fourier analysis of raw image data, and "teaching" the computer by examples of already diagnosed cases with the help of discriminant analysis. FCI offer direct and robust diagnosis of RWMA. The offered diagnosis is superior to that derived from phase and amplitude images, especially in the detection of mild RWMA.

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Experimental Investigations of the Possible Cause of Liver Appearance During Bone Scanning 1

Radiology, 1978

Rats were injected with 99mTc-Sn-diphosphonate preparation containing various concentrations of A... more Rats were injected with 99mTc-Sn-diphosphonate preparation containing various concentrations of Al+3, ranging from 0 microgram/ml to 60 microgram/ml, and whole-body rat images were obtained at two hours postinjection to assess soft-tissue uptake. Uptake (kidney and liver) occurred at approximately 20 microgram/ml Al+3. [This is the maximum allowed in pertechnetate eluate by the Nuclear Regulatory Commission (NRC). ] Increased soft-tissue uptake and progressive degradation of bone scan images occurred with higher Al+3 concentrations. Chromatographic analysis confirmed the breakdown of the radiopharmaceutical preparation containing 20 microgram/ml or more Al+3. Millipore filtration showed no evidence of large colloid particles (greater than 0.2 micrometer).

Ketamine and transcranial magnetic stimulation treatment for bipolar II disorder: a case report

Journal of Medical Case Reports, 2015

To the best of our knowledge, this is the first case report of successful treatment for bipolar I... more To the best of our knowledge, this is the first case report of successful treatment for bipolar II disorder using a combined ketamine and transcranial magnetic stimulation treatment. A 43-year-old Caucasian unemployed man presented to us with treatment-resistant bipolar II disorder, currently in a mixed state. A psychometric assessment and brain single-photon emission computer tomography scan were conducted at baseline. His psychometric assessment revealed severe depressive and manic symptoms that were consistent with bipolar II disorder. Findings from a brain single-photon emission computer tomography scan converged with those from his psychometric assessment. The combined ketamine and transcranial magnetic stimulation treatment was administered a total of 24 times over five months, with his ketamine dosage increased from 50mg at the first treatment to 600mg by the last. Starting after the second treatment, he reported substantial improvements in his symptoms. A follow-up psychometric assessment and brain single-photon emission computer tomography scan five months later revealed substantial blood flow increases in the previously deficient areas. We provide preliminary evidence for a treatment method that magnifies the therapeutic benefits of infused ketamine along with transcranial magnetic stimulation. We postulate that this may be based on an interaction at the level of the relevant cortico-thalamo-cortical circuit(s).

Patient perception and preference for diagnostic tests of intestinal inflammation

Gastroenterology, 2000

AGAA1369 54 wks, serious adverse events were reported in 21% pbo vs 17% infliximab and serious in... more AGAA1369 54 wks, serious adverse events were reported in 21% pbo vs 17% infliximab and serious infections in 8% pbo vs 6% infliximab. Three of 86 pbo pts (3.5%) died compared with 5 of 342 infliximab pts (1.5%). Infusion reactions occurred infrequently (-2% pbo, -5% infliximab), were generally mild and transient, and did not increase over time. No serious infusion reactions were reported. One case of lymphoma and I possible case of drug-induced lupus (mild and reversible) occurred among infliximabtreated pts. Assessment of jo int damage by x-ray at 54 wks showed 7-8% progression in pbo compared to 0% in infliximab pts (p<O.OOI). Radiologic benefit with infliximab occurred in both clinical responders and non-responders. Conclusion: Long-term therapy with inftiximab was well tolerated in combination with MTX in RA pts. Now in two chronic inflammatory diseases, infliximab halts end organ injury: healing of mucosal damage in CD (D'Haens, et al., Gastroenterology, 1999) and prevention of further jo int damage in RA. Background;The radiolabled white cell scan has been shown to be an accurate method of detecting intestinal inflammation. Its usefulness is further assessed by determining what diagnostic tests individuals might prefer in the diagnosis of inflammatory bowel disease. Method;Two survey groups are included in this study: one with IBD which has experienced all of the diagnostic tests in question, and one which has experienced none of them (naive group). A questionnare was administered describing the preparation and performance of colonoscopy (C), barium enema (B) and technitium labled white cell scan (WCS), then asking the above subjects which test they would prefer. In addition to preference, subjects were asked to rank the tests according to perceived pain, embarrassemnt, inconvenience and danger. Results;Both Groups had significantly greater preference for WCS than either C or B (p< O.OI by Wilcoxon signed rank tests). Ranks were similar for discomfort, embarrassment, inconvenience and danger except that the naive group expected C to be significantly more painful and embarrassing than B. WCS was perceived as more inconvenient than C but less inconvenient than B in the IBD group. Conclusion; The usefullness of the WCS in the diagnosis of IBD is further established by its perceived advantages over other methods by both IBD patients and healthy individuals. 6228 MODIFICATION OF INTRACELLULAR CYTOKINES BY ANTI-CD4 ANTffiODIES IN CROHN'S DISEASE.

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Assessment of the usefulness of a diagnostic test: A survey of patient preference for diagnostic techniques in the evaluation of intestinal inflammation

by Dan Pavel and Alan Schwartz

BMC medical research …, 2001

Background: In order to assess the usefulness of radiolabeled white cell scanning in the diagnosi... more Background: In order to assess the usefulness of radiolabeled white cell scanning in the diagnosis of intestinal inflammation, subjects were asked to rank several dimensions of preference for white cell scanning in relation to other diagnostic tests. Two groups were surveyed: one known to have inflammatory bowel disease and the second not familiar in most cases with the tests. Subjects were asked to rank preference for each of seven tests: radiolabeled white cell scan, colonoscopy, barium enema, sigmoidoscopy, enteroclysis, stool analysis and laparotomy for the diagnosis of IBD and impressions of discomfort, embarrassment, inconvenience and danger related to each test. Mean rank scores were calculated, test ranks compared within groups and significance determined by the Wilcoxon rank test.

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IC-P1-044: Differential and staging of dementia with comorbidity: Brain SPECT contribution

Alzheimer's & Dementia, 2008

2) , was utilized. Two identical triple head gamma cameras (Prism 3000XP) were used (3) with ultr... more 2) , was utilized. Two identical triple head gamma cameras (Prism 3000XP) were used (3) with ultra high resolution fan beam collimators. The radiopharmaceutical administered was 99mTc-HMPAO, with dose adjusted for patient weight. Image reconstruction was performed by filtered back projection, including a Parzen 4 filtering. The resulting slice stack underwent a 3D smoothing with low pass filtering followed by a linear attenuation correction, oblique reorientation and summation of the original reconstructed slices by a factor of 2. This resulted in a slice thickness of approx 4.4 mm. The orthogonal slices were then obtained and supplemented by a fourth set, namely the temporal slices (along the temporal long axis). The data were then transferred to a special work station (4) where a discrete 21 shades color code was used and automatic volume rendered images were obtained and displayed in four, fixed levels of thresholding (55,65, 85 & 90 %). When needed (follow-up SPECT-s and/or contemporary MRI studies) an automatic realignment method (based on a Mutual Information algorithm) was used. In addition a set of eight 3D functional surface displays, normalized to the Talairach space, were obtained via an adaptation of the Neurostat automatic software (Minoshima 1992) (5) . The end product is comprised of 4 display pages ( first 2 pages include the orthogonal and temporal slices, the 3-d page has the 6 views of each of the 4 thresholded volume renderings and, on the 4-th page displays the eight views of the surface images. To simplify the presentation and discussion of cases, a summary one line display, which includes the key images, was also generated (see ).

Assessment of left ventricular function by radionuclide angiography during induced supraventricular tachycardia

Electrocardiographically synchronized radionuclide angiography was performed before, during and a... more Electrocardiographically synchronized radionuclide angiography was performed before, during and after induced paroxysmal supraventricular tachycardia in I3 patients. Data were acquired with a computer-interfaced Anger camera in a left anterior oblique projection. No data were acquired during tachycardia until tachycardia had been sustained for I minute. Patients ranged in age from 20 to 64 years (mean f standard deviation 42 f 14.5). Three patients had organic heart disease and 10 did not. Baseline and tachycardia heart rates (beatsimin)

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Radionuclide regurgitant index: Value and limitations

The radionuclide regurgitant index, defined as left ventricular/right ventricular stroke counts o... more The radionuclide regurgitant index, defined as left ventricular/right ventricular stroke counts obtained from gated equilibrium studies, has been reported to predict the presence and severity of left-sided valve regurgitation. This study evaluated the radionuclide regurgitant index in 100 patients in whom left-sided valve regurgitation was angiographically graded (0 to 4+) with regard to most severe mitral or aortic regurgitation. Regurgitation was graded 0 in 44 of the 100 patients, l+ in 22, 2-I in 8, 3-F in 8 and 4+ in 20.

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Erythromycin stearate as prokinetic agent in postvagotomy gastroparesis

Digestive Diseases and Sciences, 1990

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Visualization of Atrial Myocardium with TI-201: Case Report

Clinical Nuclear Medicine, 1981

A case of right atrial visualization on Tl-201 imaging in a patient with marked right atrial enla... more A case of right atrial visualization on Tl-201 imaging in a patient with marked right atrial enlargement secondary to atrial septal defect is described. The misinterpretation of Tl-201 an gated cardiac studies on initial inspection, due to this unusual finding, and the importance of obtaining special lateral and oblique view for correct identification of cardiac chambers are discussed.

Tricuspid Insufficiency Detected by Equilibrium Gated Radionuclide Study

Clinical Nuclear Medicine, 1981

The results of a gated radionuclide cardiac study are reported in a patient with biventricular fa... more The results of a gated radionuclide cardiac study are reported in a patient with biventricular failure and tricuspid insufficiency demonstrated by clinical evaluation, M-mode and 2-D sector echocardiography, and cardia catheterization. The processed gated radionuclide cardiac study showed a left ventricular/right ventricular stroke volume ratio of 0.5; expansion of the hepatic blood pool demonstrated by hepatic time activity curve and calculation of an &amp;amp;quot;&amp;amp;#39;expansion fraction&amp;amp;quot;; and synchronous changes of count rate of the atrial and hepatic regions detected by phase analysis (similar phase shifts).

Incidence and Consequences of Breast Artifacts in Radionuclide Cardiac Studies

Clinical Nuclear Medicine, 1982

A retrospective evaluation was done on 426 radionuclide cardiac studies performed on female patie... more A retrospective evaluation was done on 426 radionuclide cardiac studies performed on female patients at our institution from January through September, 1980. These procedures included pyrophosphate (PYP) myocardial scans, resting and exercise Tl-201 studies, and gated equilibrium studies. The purpose of this evaluation was to document the incidence and possible consequences of breast artifacts in various cardiac procedures. We found the incidence to range from 30 to 50% of the studies performed, and both the incidence and type of artifact encountered varied with the type of procedure performed. Furthermore, 13 to 35% of patients had artifacts directly overlying the myocardium. The possible consequences, including potential misdiagnosis, interference with computer derived quantitative parameters, and the technical maneuvers necessary to avoid or alleviate these problems are discussed.

The Hot Rectus Abdominis Muscle Sign

Clinical Nuclear Medicine, 1999

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Potential False-positive In-111 Labeled Leukocyte Study in a Patient with Orthopedic Hip Arthroplasty

Clinical Nuclear Medicine, 1992

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Positive Captopril Renal Scintigraphy in a Patient With Extensive Bilateral Renal Interlobar Arterial Disease

Clinical Nuclear Medicine, 1994

The authors determined an unusual cause of renovascular hypertension in a 29-year-old man with th... more The authors determined an unusual cause of renovascular hypertension in a 29-year-old man with the recent onset of hypertension and a history of intravenous substance abuse. Captopril renal scintigraphy (CRS) demonstrated bilateral renogram changes and a decrease in estimated global glomerular filtration rate. The abdominal aortogram failed to show renal artery or branch artery stenosis. Magnified selective views of the kidneys demonstrated extensive, bilateral, small vessel interlobar disease. Two major points are illustrated in this patient. First, in the presence of positive CRS results and a history of renovascular hypertension, bilateral, selective, magnified renal angiography should be performed in accordance with standard abdominal aortic views when large vessel disease is not detected. Second, although surgical intervention is not an option in such patients, finding the cause of hypertension is important for patient management.

Ventricular phase analysis of radionuclide gated studies

The American Journal of Cardiology, 1980

Sequential regional phase mapping of radionuclide gated biventriculograms in patients with sustained ventricular tachycardia: Close correlation with electrophysiologic characteristics

American Heart Journal, 1982

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