A COMPARISON OF REST SESTAMIBI AND REST-REDISTRIBUTION THALLIUM SINGLE PHOTON-EMISSION TOMOGRAPHY - POSSIBLE IMPLICATIONS FOR MYOCARDIAL VIABILITY DETECTION IN INFARCTED PATIENTS

Thirty patients (26 men, 4 women, mean age 61 +/- 8 years) who had suffered myocardial infarction 15 +/- 6 months previously, were submitted to (1) standard stress-redistribution thallium-201 single photon emission tomography (SPET), (2) rest-redistribution Tl-201 SPET and (3) stress-rest technetium-99m sestamibi SPET. Uptake modifications in relation to exercise-induced defects were evaluated in a total of 390 myocardial segments. Tracer uptake was scored as normal ( = 0), mildly reduced ( = 1), apparently reduced ( = 2), severely reduced ( = 3) or absent ( = 4). Comparison of stress studies failed to show any statistical difference (58% segmental abnormalities with sestamibi vs 61% with thallium). Uptake abnormalities (score 1-4) were detected in 55% of the segments wihest sestamibi, 55% with standard thallium redistribution, 55% with early imaging after thallium injection at rest and 54% with 3-h delayed rest imaging (P = NS). Absence of tracer uptake (score = 4) under resting conditions was recorded in 75 (19%) segments with standard Tl-201 redistribution, 75 (19%) with rest sestamibi, 70 (18%) with rest Tl-201 imaging and 62 (16%) with rst-rdistruion Tl-201 (P < 0.05 vs other imaging modalities). Thus, 3-h delayed rest thallium imaging detected reversibility of uptake defects in a significantly higher number of myocardial segments. This finding might have important implications for both tracer and technique selection when myocardial viability is the main clinical issue.