[Ischemic heart disease evaluated by exercise stress thallium-201 myocardial scintigraphy: a comparison of SPECT and bull's eye display].

T1-201 stress myocardial scintigraphy was performed in 35 cases of ischemic heart disease (angina pectoris and myocardial infarction) to assess the accuracy of SPECT and bull's eye display in the quantitative diagnosis of coronary artery lesions. We evaluated the sites of ischemic heart disease using the following methods: 1. SPECT (visual): visual evaluation by myocardial SPECT images. 2. SPECT +bull's eye (visual): visual evaluation by stress, delayed and washout images of bull's eye display. 3. bull's eye (quantitative): quantitative evaluation by the washout rate and % uptake. The diagnostic accuracy of method 2 was higher than that of method 1 in all coronary arterial vessels; LAD (74% vs 80%), LCX (60% vs 63%) and RCA (57% vs 60%). The diagnostic accuracy of method 3 was approximately equal to that of method 2. The diagnostic accuracy of method 2 was higher than of method 1 in patients with three-vessel disease (43% vs 67%), while there was no such difference in patients with both single and two-vessel disease. Moreover, the diagnostic accuracy of method 3 was approximately equal to that of method 2 in patients with three-vessel disease. In some cases the redistribution was recognized only by using washout images or by calculating the washout rate as a quantitative evaluation. In conclusion, the bull's eye display improved the diagnostic accuracy of T1-201 scintigraphy, but the quantitative analysis did not further improve the accuracy. However, there were some possibilities of evaluating the redistribution in some cases by using quantitative analysis.(ABSTRACT TRUNCATED AT 250 WORDS)

[Factors influencing exercise tolerance in patients with myocardial infarction as elucidated by Tl-201 myocardial scintigraphy].

Measurements of O2 consumption during treadmill exercise tests and Tl-201 myocardial scintigraphy were performed in 17 cases of myocardial infarction to elucidate O2 consumption at an anaerobic threshold ATVO2 as an adequate index of exercise tolerance, and the scintigraphic indices influencing the exercise tolerance. ATVO2 was obtained using the method of Wasserman and Davisand corrected by body weight. The scintigraphic indices such as the location, extent (residual myocardium), and severity (% uptake) of myocardial infarction were obtained from SPECT and bull's eye displays on Tl-201 myocardial scintigraphy. ATVO2 was correlated with theoretical VO2max as obtained by the predicted maximal heart rate (r = 0.56, p less than 0.01) and with left ventricular ejection fraction as obtained by radionuclide left ventriculography (r = 0.59, p less than 0.01). There was no significant difference between ATVO2 in cases of anterior wall infarction and those of inferior (and/or lateral wall) infarction. There was no significant correlation between % uptake and ATVO2. However, the residual myocardium showed a significant correlation with ATVO2 (r = 0.61, p less than 0.01). In conclusion, 1) ATVO2 is an adequate index of exercise tolerance and reflects cardiac function. 2) The extent of the residual myocardium is most strongly influenced by ATVO2 among the indices of myocardial damage as obtained by Tl-201 myocardial scintigraphy.

[Indications for coronary revascularization and the postoperative evaluations using Tl-201 exercise myocardial scintigraphy and a bull's eye display].

Tl-201 exercise myocardial scintigraphy and quantitative analysis using bull's eye display were performed in 31 cases (18 bypass cases, 13 PTCA cases) to determine the indications for coronary artery bypass surgery and PTCA, and to evaluate postoperative improvement. Regions of interest (ROI) corresponding to each revascularized area were created on a bull's eye display. Then the washout rates (WR) and % uptakes were expressed as percentages. Improvement was judged to have occurred if the revascularized coronary artery was patent and both the WR and % uptake returned to the normal range as determined from the examinations of 20 normal cases. The results were as follows: 1. The preoperative mean WR of the improved areas (30 vessels) was 19 +- 15%, while that of the unimproved areas (15 vessels) was 35 +- 7%. We assumed that the area was suitable for revascularization when the preoperative WR was less than 25% which was in the lower limit of the normal range. Then, 18 vessels were judged to be suitable for surgery, and subsequent postoperative improvement was obtained in the 17 areas. 2. In 32 scintigraphically-improved areas, 30 vessels were angiographically patent, while five vessels were obliterated angiographically in 13 scintigraphically-unimproved areas (diagnostic validity was 76% of all 45 vessels). 3. The exercise tolerance increased significantly (p less than 0.01) from 8.7 +- 2.0 min to 11.6 +- 2.5 min in the improved cases in which all the revascularized areas were improved after revascularization. There was no change of the exercise tolerance (before: 9.4 +- 3.4 min, after: 9.4 +- 2.5 min) in the unimproved cases in which all the revascularized areas were unimproved. 4. Quantitative analysis was useful for objective evaluation, because the visual evaluations did not always agree with the quantitative evaluation. We concluded that the area with the preoperative WR less than the normal range is suitable for revascularization. As the scintigraphic evaluation was in accord with improved exercise tolerance and with patency as observed by coronary angiography, our method seems useful for postoperative follow-up.