'Reverse redistribution pattern' during myocardial perfusion imaging with 99Tcm-MIBI.

We retrospectively studied 540 consecutive patients with coronary artery disease (CAD) undergoing 99Tcm-methoxy-isobutyl-isonitrile (99Tcm-MIBI) myocardial single photon emission tomography (SPET) to determine the incidence of the 'reverse redistribution pattern' (RRP). RRP is similar to reverse redistribution (RR) in 201Tl myocardial SPET and is defined as the presence of a perfusion defect on the resting cardiac image, rather than on the exercise image. Our results confirmed 30 (5.6%) patients to have RRP, all of whom underwent diagnostic coronary angiography. None of the 30 patients showed RRP in the territory of the left circumflex coronary artery. RRP occurred in the territory of the left anterior descending coronary artery (LAD) in 16 patients, 12 of whom had a normal LAD. Fourteen patients presented with RRP in the territory of the right coronary artery, all of whom had normal coronary arteries. RRP in 99Tcm-MIBI myocardial SPET is less common than RR in 201Tl myocardial SPET and is frequently associated with normal coronary arteries. RRP with 99Tc(m)-MIBI seems to be of little value in the diagnosis of CAD.