Rest-Injected Thallium-201 Redistribution and Technetium-99m Methoxyisobutylisonitrile Uptake in Coronary Artery Disease: Relation to the Severity of Coronary Artery Disease

To compare rest-injected thallium-201 (T1) redistribution and resting technetium-99m methoxyisobutylisonitrile (99mTc-MIBI) myocardial uptake in chronic coronary artery disease (CAD), 15 patients with angiographically proven CAD and left ventricular (LV) dysfunction (ejection fraction 34% +9%) were studied. All patients underwent rest-redistribution T1 and resting 99mTc-MIBI cardiac imaging. Gated 99mTc-MIBI images were also acquired to assess regional LV wall motion (WM). Myocardial segments (n = 225) were divided into three groups on the basis of the degree of coronary artery stenosis: group 1 (total occlusion, n-- 82), group 2 (50%- 99% of stenosis, n= 84) and group 3 (< 50% of stenosis, n = 59). WM was significantly worse in groups 1 and 2 compared to group 3 (P<0.001), but no difference was observed between groups 1 and 2. T1 and 99mTc-MIBI uptake were significantly lower in groups 1 and 2 compared to group 3 (P < 0.001), and in group 1 compared to group 2 (P<0.001). When T1 and 99mTc-MIBI uptake were directly compared, T1 uptake was higher than 99mTc-MIBI uptake in group 1 (P