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M J Cramer

Publications and source records attributed to M J Cramer.

26 records · Page 2Linked to original sources
PubMed1990

ECG-gated and static technetium-99m-SESTAMIBI planar myocardial perfusion imaging: a comparison with thallium-201 and study of observer variabilities.

To assess the diagnostic accuracy of planar diastolic and static Technetium-99m-SESTAMIBI, myocardial perfusion imaging at rest and during exercise, was performed in 60 consecutive patients. The results were compared with coronary angiographic findings, obtained within 3 months of the exercise test and Thallium-201 images, obtained on the same day and to the same exercise level as Technetium-99m-SESTAMIBI exercise. Exact segmental concordance between static Technetium-99m-SESTAMIBI and Thallium-201 was 77% and between the diastolic images and Thallium-201 76%. Concordance between static and diastolic images was 92%. Nineteen percent of all 900 segments demonstrated ischemia with both static and diastolic Technetium-99m-SESTAMIBI and 20% with Thallium-201. Overall sensitivity to detect hemodynamically significant coronary artery disease with static Technetium-99m-SESTAMIBI was 86%, specificity 78%, with diastolic images 89% and 70% and with Thallium-201 89% and 78% (differences not significant). Vessel-specific comparative detection rates revealed no statistical significant differences between both radiopharmaceuticals as well. Intra-observer variability for the static images was 12%, for the diastolic images 21% and Thallium-201 14%. Inter-observer variability for the static images was 14%, diastolic images 24%, and Thallium-201 17%. Although the physical characteristics of Tc-SESTAMIBI enable to perform high-count density imaging and electrocardiographic gating, no significant differences are found when planar diastolic and static Technetium-99m-SESTAMIBI images are compared with Thallium-201 and are well within observer variabilities.

Coronary Disease↗
PubMed1989

Detection of multivessel disease in patients with sustained myocardial infarction by thallium 201 myocardial scintigraphy: no additional value of quantitative analysis.

This study was performed to determine the value of visual and quantitative thallium 201 scintigraphy for the detection of multivessel disease in 67 patients with a sustained transmural myocardial infarction. Also the viability of the myocardial regions corresponding to pathologic Q-waves was evaluated. Of the 67 patients, 51 patients had multivessel coronary artery disease (76%). The sensitivity of the exercise test was 53%, of thallium scintigraphy 69%, when interpreted visually, and 67%, when analysed quantitatively. The specificity of these methods was 69%, 56%, and 50%, respectively. Sixty-two infarct-related flow regions were detected by visual analysis of the thallium scans, total redistribution was observed in 11/62 (18%) of patients, partial redistribution in 26/62 (42%), and no redistribution in 25/62 (40%) of patients. The infarct-related areas with total redistribution on the thallium scintigrams were more likely to be associated with normal or hypokinetic wall motion (7/11: 64%) than the areas with a persistent defect (7/25:28%) (P = 0.05), which were more related with akinetic or dyskinetic wall motion. Based on our results, it is concluded that 1) both visual and quantitative analysis of thallium exercise scintigraphy have limited value to predict the presence or absence of multivessel coronary artery disease in patients with sustained myocardial infarction, and 2) exercise-induced thallium redistribution may occur within the infarct zone, suggesting the presence of viable but jeopardized myocardium in presumed fibrotic myocardial areas.

Coronary Angiography↗
PubMedDate not supplied

Quantitative thallium-201 myocardial exercise scintigraphy in normal subjects and patients with normal coronary arteries.

Quantitative thallium-201 myocardial exercise scintigraphy was tested in two patient populations representing alternative standards for cardiac normality: group I comprised 18 male uncatheterized patients with a low likelihood of coronary artery disease (CAD); group II contained 41 patients with normal coronary arteriograms. Group I patients were younger, they achieved a higher rate-pressure product than group II patients; all had normal findings by physical examination and electrocardiography at rest and exercise. Group II patients comprised 21 females, 11 patients showed abnormal electrocardiography at rest, and five patients showed ischemic ST depression during exercise. Twelve patients had signs of minimal CAD. Twelve patients revealed abnormal visual and quantitative thallium findings, three of these patients had minimal CAD. Profiles of uptake and washout of thallium-201 were derived from both patient groups, and compared with normal limits developed by Maddahi et al. Furthermore, low likelihood and angiographically normal patients may differ substantially, and both sets of normal patients should be considered when establishing criteria for abnormality in exercise thallium imaging. When commercial software containing normal limits for quantitative analysis of exercise thallium-201 imaging is used in clinical practice, it is mandatory to compare these with normal limits of uptake and washout of thallium-201, derived from the less heterogeneous group of low-likelihood subjects, which should be used in selecting a normal population to define normality.

Adult↗
PubMedDate not supplied

Safety and efficacy of computerized closed-loop delivery of arbutamine: a new pharmacologic myocardial stress modality for the assessment of coronary artery disease. The European Arbutamine Study Group.

This study evaluated the efficacy of computer-controlled closed-loop delivery of a new synthetic catecholamine, arbutamine, when given to induce myocardial ischemia detected by electrocardiography and echocardiography with a high (10 beats/min/min) and low (6 beats/min/min) rate of increase in heart rate (heart rate slope) in 70 patients with coronary artery disease. The electrocardiographic sensitivity for the detection of myocardial ischemia was 52% for the low slope and 51% for the high slope. The corresponding figures for echocardiographic sensitivity were 83% and 79% for the low and high slopes, respectively. There were no significant differences in changes from baseline to maximum in pharmacodynamic variables, although the mean times to reach maximum heart rate and systolic blood pressure were 1.4 minutes shorter (p = 0.001) and 3.7 minutes shorter (p < 0.05), respectively, for the high-slope regimen. The duration of the infusion was shorter (p < 0.001) for the high slope. In this study, closed-loop arbutamine administration was effective and safe in the detection of coronary artery disease for both heart rate slope regimens.

Adult↗
PubMedDate not supplied

Detection of coronary artery disease: comparison between technetium 99m-labeled sestamibi single-photon emission computed tomography and two-dimensional echocardiography with dipyridamole low-level exercise-stress.

BACKGROUND: Myocardial perfusion imaging in conjunction with dipyridamole low-level exercise stress has proved its value in the evaluation of patients with coronary artery disease (CAD). Simultaneous wall motion analysis by two-dimensional (2D) echocardiography may provide additional information beyond that obtained by myocardial perfusion imaging alone. The purpose of this study was to compare 99mTc-labeled sestamibi single-photon emission computed tomography (SPECT) and 2D echocardiography for the evaluation of CAD according to a dipyridamole low-level bicycle exercise stress protocol. METHODS AND RESULTS: We studied 35 consecutive patients referred for the evaluation of chest pain who had undergone coronary arteriography. 99mTc-labeled sestamibi SPECT and 2D echocardiography agreed in 27 patients (80%) studied for overall detection of CAD. On a segmental basis, agreement was found between SPECT and 2D echocardiography in 124 (73%) of 170 segments (Cohen's kappa = 0.43). The accuracy of the combined assessment of myocardial perfusion and echocardiographic wall motion in detecting CAD was 86%, which was not different from the accuracy of SPECT alone (80%; difference not significant) but significantly higher than for 2D echocardiography alone (71%; p = 0.03). In the detection of individual coronary artery stenoses, SPECT had a significantly higher accuracy for detecting left anterior descending coronary artery lesions than had 2D echocardiography (80% vs 60%; p < 0.01); combining the two method did not improve the accuracy (80%). The combined assessment slightly improved the accuracy for detecting left circumflex coronary artery stenoses from 71% to 83% (p = 0.05). CONCLUSION: The combined simultaneous assessment of myocardial perfusion by 99mTc-labeled sestamibi SPECT and wall motion by 2D echocardiography did not significantly improve overall accuracy over that obtained by 99mTc-labeled sestamibi SPECT alone. Therefore 99mTc-labeled sestamibi SPECT with dipyridamole low-level exercise stress appears the preferred imaging modality for the evaluation of patients with CAD.

Adult↗