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Unlabelled: Perfusion scintigrams with Technetium-labeled microspheres were performed in 60 patients undergoing selective coronary angiography. The scintigrams were analyzed semiquantitatively with the aid of a computer. In addition, angiograms were quantitated with regard to proximal obstructions as well as regional wall changes of the left ventricle (VCF)., Results: 1. A reduction of scintigraphic activity was already seen in narrowings of lesser degrees (50%); 2. scintigraphic activity followed the degree of obstruction rather than the contraction abnormality. Perfusion scintigrams are helpful in selecting patients for revascularization.

Unlabelled: Regional myocardial blood flow was studied at rest in 72 patients with a typical history of angina pectoris and/or myocardial infarction using the 133Xenon clearance technique. 62 patients had isolated greater than 50% obstructions of the left anterior descending or of the left circumflex branch, 10 patients had segmental asynergy yet no or only minimal (less than 35%) coronary obstructions. In each patient, flow of the poststenotic (asynergic) LV wall area was related to flow of the normal area (= 100%). Coronary obstructions were measured in multiple projections using a vernier, and segmental wall motion was quantitated by systolic halfaxial shortening., Results: A progressive decrease of poststenotic flow was found with increasing severity of coronary obstructions: in relation to the respective normal areas, poststenotic flow was reduced to 84% distal to 50-75% obstructions (p less than 0.01), to 75% distal to 76-90% obstructions (p less than 0.0005), and to 67% distal to less than 90% obstructions (p less than 0.0005). However, analysis of poststenotic LV wall motion suggested that flow was correlated more closely to poststenotic wall motion: in hypokinetic areas, flow was reduced to 75% (p less than 0.0005), and in akinetic areas to 55% (p less than 0.0005) whereas in poststenotic areas with normal wall motion resting flow was normal regardless of the severity of coronary obstructions. Furthermore, the reduction of flow in asynergic areas of patients without coronary obstructions was comparable to flow in asynergic areas supplied by severely stenosed vessels. Thus in chronic coronary heart disease, regional myocardial blood flow correlates not only to the severity of coronary obstructions but also to segmental left ventricular wall motion.

The regional uptake of Thallium-201 is correlated with the regional distribution of cardiac output in the myocardium as well as in skeletal muscle. Thallium-201 perfusion scans will detect peripheral occlusive arterial disease (POAD) as well as coronary heart disease (CHD). In a prospective study we examined POAD patients and CHD patients by both myocardial and leg stress scintigraphy. In normals the uptake ratio of both calves was 1.03 +/- 0.05 (mean +/- SD), while in all patients with proven POAD the ratio was higher than 1.2. In 12 of 16 patients with myocardial infarction the high ratio indicated a coincidence of POAD and CAD, confirmed by other techniques in all but one patient. In patients with suspected CHD there was an increased ratio in 8 of 21;6 of these patients also had an abnormal myocardial stress scan, while there were only 4 abnormal scans in the 13 patients with normal leg uptake. In 19 of 26 patients with known POAD the myocardial stress scan was abnormal, indicating CHD in 75% of this group. This was confirmed in most patients by coronary angiography. The combination of myocardial and leg stress scan can be carried out without further radiation exposure to the patient and in a few minutes. It is a new approach to determine the possible coincidence between POAD and CHD; it should be performed in all patients referred for TI-201 myocardial stress scintigraphy.

Unlabelled: The effect of isosorbide dinitrate (ISDN) (10 mg sublingually) on myocardial perfusion during ischemic conditions was analyzed in 14 patients with angiographically severe coronary artery disease and typical angina pectoris, using the 201-Thallium-myocardial scintigraphy. All patients underwent two identical scintigrams with the same work load during bicycle ergometry; a control scintigram leading to angina and ST-depressions of greater than 0.1 mV was followed 4--6 weeks later by a scintigram after ISDN; all drugs -- except sublingual nitroglycerin -- were withheld for an entire week. --, Results: 25 of 39 new or enlarged, exercise-induced defects (64%) were normalyzed after ISDN; 14 new or enlarged defects remained unchanged (p less than 0.0005). In the 11 patients, in whom ISDN led to complete abolishment of angina, 23 of 30 new defects (76%) were normalized against none in the 3 patients with persistent angina and ST-depressions. Quantitation of perfusion was attempted by calculating the average impulse rate (counts/min/matrix point): in those patients reacting favorably to ISDN average impulse rate decreased significantly especially in the normal area (p less than 0.001), resulting in a more homogeneous distribution of Thallium activity, indicating a marked reduction in local oxygen consumption.