Reverse redistribution in resting thallium-201 myocardial scintigraphy in patients with coronary artery disease: Relation to coronary anatomy and ventricular function

We studied 25 male patients, with coronary artery disease, mean age 56 ± 8 yr. All underwent ²⁰¹Tl rest-redistribution and resting ^99mTc methoxyisobutyl isonitrile (MIBI) cardiac imaging. Regional ²⁰¹Tl and MIBI uptake were quantitatively analyzed. Regional left ventricular wall motion (WM) was visually assessed on MIBI gated images using a three-point scale (0 = normal, 1 = hypokinetic, 2 = a/dyskinetic). Two patterns of reverse redistribution (RR) were identified: RR-A when ²⁰¹Tl uptake was normal on rest images and abnormal on redistribution images, and RR-B when ²⁰¹Tl uptake was abnormal on rest images and a significant decrease in uptake was observed on redistribution images. Of the total 375 myocardial segments analyzed, 229 were classified as normal (NI), 40 as reversible defect (RD), 74 as irreversible defect (ID); 26 showed RR-A while 6 myocardial segments had RR-B. Myocardial segments with RR-A differed from NI in the degree of coronary artery stenosis (81% ± 33% versus 57% ± 39%, respectively, p <0.05), in WM score (1.1 ± 0.7 versus 0.5 ± 0.6, respectively, p <0.01), and in MIBI uptake (81% ± 10% versus 92% ± 9%, respectively, p <0.0001). Moreover, the percent of myocardial segments supplied by a totally occluded coronary artery was significantly higher (p <0.05) in myocardial segments with RR-A (46%) than in NI (22%). Segments with RR-B did not show any significant difference either from RD and ID. These results suggest that myocardial segments with RR-A on resting ²⁰¹Tl images have impaired function and are supplied by severely stenosed coronary arteries and should not be considered normal.