Papers by Jamshid Maddahi
Journal of Nuclear Medicine Technology, Jun 1, 1991
This is the second article in the four-part series on "New Radiopharmaceutica/s." Upon completion... more This is the second article in the four-part series on "New Radiopharmaceutica/s." Upon completion of this article the reader should be able to: (1) identify imaging characteristics of technetium-99m-sestamibi and ( ) understand the reconstruction and processing protocol.
Journal of Nuclear Cardiology, Feb 19, 2010
Background. We developed a cardiac SPECT system (X-ACT) with low dose volume CT transmission-base... more Background. We developed a cardiac SPECT system (X-ACT) with low dose volume CT transmission-based attenuation correction (AC). Three solid-state detectors are configured to form a triple-head system for emission scans and reconfigured to form a 69-cm field-of-view detector arc for transmission scans. A near mono-energetic transmission line source is produced from the collimated fluorescence x-ray emitted from a lead target when the target is illuminated by a narrow polychromatic x-ray beam from an x-ray tube. Transmission scans can be completed in 1 min with insignificant patient dose (deep dose equivalent <5 lSv). Methods. We used phantom studies to evaluate (1) the accuracy of the reconstructed attenuation maps, (2) the effect of AC on image uniformity, and (3) the effect of AC on defect contrast (DC). The phantoms we used included an ACR phantom, an anthropomorphic phantom with a uniform cardiac insert, and an anthropomorphic phantom with two defects in the cardiac insert. Results. The reconstructed attenuation coefficient of water at 140 keV was .150 ± .003/cm in the uniform region of the ACR phantom, .151 ± .003/cm and .151 ± .002/cm in the liver and cardiac regions of the anthropomorphic phantom. The ACR phantom images with AC showed correction of the bowing effect due to attenuation in the images without AC (NC). The 17-segment scores of the images of the uniform cardiac insert were 78.3 ± 6.5 before and 87.9 ± 3.3 after AC (average ± standard deviation). The inferior-to-anterior wall ratio and the septal-to-lateral wall ratio were .99 and 1.16 before and 1.02 and 1.00 after AC. The DC of the two defects was .528 and .156 before and .628 and .173 after AC. Conclusion. The X-ACT system generated accurate attenuation maps with 1-minute transmission scans. AC improved image quality and uniformity over NC. (
The Journal of Nuclear Medicine, Jul 28, 2014
Absolute quantitation of myocardial blood flow (MBF) by PET is an established method of analyzing... more Absolute quantitation of myocardial blood flow (MBF) by PET is an established method of analyzing coronary artery disease (CAD) but subject to the various shortcomings of available radiotracers. Flurpiridaz F 18 is a novel PET radiotracer that exhibits properties of an ideal tracer. Methods: A new absolute perfusion quantitation method with flurpiridaz was developed, taking advantage of the early kinetics and high first-pass extraction by the myocardium of this radiotracer, and the first-in-human measurements of MBF performed in 7 healthy subjects and 8 patients with documented CAD. PET images with time-activity curves were acquired at rest and during adenosine stress. Results: In healthy subjects, regional MBF between coronary artery territories did not differ significantly, leading to a mean global MBF of 0.73 mL/min/g at rest and 2.53 mL/min/g during stress, with a mean global myocardial flow reserve (MFR) of 3.70. CAD vascular territories with ,50% stenosis demonstrated a mean MBF of 0.73 at rest and 2.02 during stress, leading to a mean MFR of 2.97. CAD vascular territories with $50% stenosis exhibited a mean MBF of 0.86 at rest and 1.43 during stress, leading to a mean MFR of 1.86. Differences in stress MBF and MFR between normal and CAD territories, as well as between ,50% and $50% stenosis vascular territories, were significant (P , 0.01). Conclusion: Absolute quantitation of MBF in humans with the novel PET radiotracer flurpiridaz is feasible over a wide range of cardiac flow in the presence or absence of stressinducible myocardial ischemia. The significant decrease in stress MBF and ensuing MFR in CAD territories allows a clear distinction between vascular territories exhibiting stress-inducible myocardial ischemia and those with normal perfusion.
Circulation, Jan 4, 2000
W riting Group II addressed the question of whether tests that assess silent ischemia or inducibl... more W riting Group II addressed the question of whether tests that assess silent ischemia or inducible ischemia add to prognostic information gained from standard risk factors in asymptomatic patients without known coronary disease. The tests reviewed included the exercise electrocardiogram (ECG), exercise and pharmacological (stress) echocardiogram (echo), exercise and pharmacological myocardial perfusion imaging, ambulatory ECG monitoring, and positron emission tomography. These noninvasive tests detect myocardial ischemia associated with obstructive coronary artery disease (CAD). To date, their greatest application has been diagnostic, in the evaluation of patients with symptoms of angina or a previous clinical manifestation of coronary heart disease (CHD). One limitation of the methods used to detect stress-induced (exercise or pharmacological stress) myocardial ischemia is the dependence of these methods on the presence of flowlimiting coronary stenosis. As with all diagnostic studies, their predictive value is dependent on the prevalence of disease in the population tested. When used in a population with a low prevalence of CHD, such as an asymptomatic population undergoing cardiovascular screening, these tests are expected to have low positive predictive value, and the majority of positive test results represent false-positive responses (Figure). Also central to the discussions of Writing Group II was the recognition that the majority of future events among patients with CHD are related to severity of obstruction, plaque instability, and total atherosclerotic burden. 1 Writing Group II was specifically concerned with delineating the prognostic information available from these tests that could contribute toward identifying patients at higher risk for major CHD-related events.
Clinical evaluation of a low-dose, X-ray-based transmission imaging for attenuation correction of SPECT myocardial perfusion images
The Journal of Nuclear Medicine, 2009
598 Objectives A novel x-ray-based transmission (Tx) approach to cardiac SPECT attenuation correc... more 598 Objectives A novel x-ray-based transmission (Tx) approach to cardiac SPECT attenuation correction (AC) has been developed that produces high-quality Tx scans with negligible (5 μSv) patient dose and a very low incidence of misregistration. Clinical utility of this AC approach was evaluated by assessing its effect on normal SPECT myocardial perfusion count distribution. Methods 69 patients (44 males and 25 females) with a low pre-SPECT likelihood of coronary artery disease underwent same-day rest-stress SPECT with a Tc-99m labeled agent. A triple head, upright solid-state camera was used for emission and Tx scans. Using x-ray fluorescence, a mono-energetic, collimated line source was formed which allowed Tx scans to be completed in one minute. Rest (R) and stress (S) Myocardial count distributions were quantified (as % maximum) for 5 myocardial regions and 17 myocardial segments before (no AC) and after AC. Results Effect of AC on S and R regional counts are shown in [Table] (*p ...
Developments in Cardiovascular Medicine, 1984
Nuclear cardiology: which clinical questions can be answered now and in the future?
Developments in Cardiovascular Medicine, 1998
Nuclear cardiology has now become an established method for diagnosis and evaluation of coronary ... more Nuclear cardiology has now become an established method for diagnosis and evaluation of coronary artery disease (CAD). Since its introduction about two and a half decades ago, myocardial perfusion scintigraphy has become the most commonly performed method in the field of nuclear cardiology and has advanced significantly. Clinical applications have expanded from diagnosis to risk stratification of CAD and assessment of a variety of clinical conditions such as myocardial infarction, left ventricular dysfunction, and revascularization. More recently, cost-effectiveness of these procedures has been demonstrated in a variety of clinical settings. This chapter provides an overview of the clinical questions that can be answered, by myocardial perfusion imaging, now and in the future.
Journal of nuclear medicine : official publication, Society of Nuclear Medicine, 1994
The accuracy of an automated quantitative analysis of same-day rest/stress 99mTc sestamibi SPECT ... more The accuracy of an automated quantitative analysis of same-day rest/stress 99mTc sestamibi SPECT images for detection and localization of coronary artery disease (CAD) was assessed in a multicenter trial consisting of 161 patients from 7 different clinical sites utilizing various camera computer systems. Of the 161 patients, 102 had angiographically documented coronary artery disease, 22 had normal coronary arteriograms, and 37 had a low (< 5%) likelihood of coronary artery disease based on their age, sex, symptoms and the results of their exercise electrocardiograms. The patients were studied using previously optimized image acquisition and processing protocols. An additional population consisting of 45 patients with single-vessel disease were evaluated to determine the optimal criteria for detection of CAD. The quantitative analysis method was associated with an overall sensitivity of 87%, specificity of 36%, and normalcy rate (true negative rate in the low likelihood patients)...
[Detection of coronary artery disease with new non-invasive techniques (author's transl)]
Herz, 1980
Journal of nuclear medicine : official publication, Society of Nuclear Medicine, 1986
Previous quantitation of exercise-redistribution planar 201TI scintigraphy has shown high sensiti... more Previous quantitation of exercise-redistribution planar 201TI scintigraphy has shown high sensitivity and specificity in the detection of coronary artery disease and improved detection of individual coronary stenoses over visual analysis. By using similar methodology based on the circumferential profile method, we studied 133 patients to quantitatively assess the extent, depth, and severity of thallium defects compared with consensus visual analysis. These quantitative measurements are objective, requiring only three operator interactions. In comparing quantitative and visual results, a close correlation was found for measurement of extent of thallium defect (r = 0.73) and severity of defect (r = 0.79). In detecting patients with the high-risk scintigraphic pattern of a severe stress thallium defect, a quantitative depth score of greater than or equal to 36 had an 81% sensitivity and an 82% specificity. Thus, this nearly automatic, computerized quantitative method allows objective d...
Quantitative interpretation of myocardial Tl201 single-photon emission computerized tomograms: A probabilistic approach to the assessment of coronary artery disease
Probabilistic criteria for abnormality would enhance application of stress-redistribution Tl-201 ... more Probabilistic criteria for abnormality would enhance application of stress-redistribution Tl-201 rotational tomography (tomo) for evaluation of coronary artery disease (CAD). Thus, 91 pts were studied, of whom 45 had angiographic CAD (greater than or equal to 50% coronary narrowing) and 46 were normal (nl). The validity of this model was prospectively tested in the remaining 51 pts (26 nls and 25 with CAD) by comparing the predicted and observed likelihood of CAD in four subgroups (I-IV). In this paper a logistic model is developed and validated that assigns a CAD likelihood to the quantified size of tomograhic myocardial perfusion defects.
Quantification of the extent and severity of myocardial ischemia in single-vessel disease using stress-redistribution thallium-201 single-photon emission computerized tomography
Single-vessel coronary artery (CA) disease (SVD) is not uniformly benign: long-term prognosis is ... more Single-vessel coronary artery (CA) disease (SVD) is not uniformly benign: long-term prognosis is likely to be related to the extent (E) and severity (S) of myocardial ischemia (isch). To assess the ability of stress thalium-201 (Tl) single photon emission computerized tomography (SPECT) to quantify E and S of isch, the authors studied 15 patients (pts) without myocardial infarction who had SVD (8 LAD, 4 RCA, and 3 LCX). SPECT cuts were analyzed using maximum count circumferential profiles (CPs) which were compared with previously established normal (nl) limits derived from 20 nl pts. E of isch was defined as the % of the CP points falling below nl, S and depth (D) of ischemia respectively expressed the total and the mean % by which the abnormal points fell below normal limits. Although all pts had SVD, the range of E, S and D of isch was wide (0 to 48% and 0 to 38% and 0 to 20% respectively). CA scores (CS) were derived using a 15-point system accounting for the distribution of the ...
Journal of Nuclear Cardiology, 2008
Clinical Nuclear Medicine, 1982
Clinical Nuclear Medicine, 1982
Clinical Nuclear Medicine, 1982
Clinical Nuclear Medicine, 1982
Clinical Nuclear Medicine, 1992
Clinical Nuclear Medicine, 1987
Clinical Nuclear Medicine, 1987
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Papers by Jamshid Maddahi