We tested the possibility of identifying areas of hibernating myocardium by the combined assessment of perfusion and metabolism using single photon emission tomography (SPET) with technetium-99m hexakis 2-methoxyisobutylisonitrile (99mTc-MIBI) and positron emission tomography (PET) with fluorine-18 fluoro-2-deoxy-D-glucose (18F-FDG). Segmental wall motion, perfusion and 18F-FDG uptake were scored in 5 segments in 14 patients with coronary artery disease (CAD), for a total number of 70 segments. Each subject underwent the following studies prior to and following coronary artery bypass grafting (CABG): first-pass radionuclide angiography, electrocardiography gated planar perfusion scintigraphy and SPET perfusion scintigraphy with 99mTc-MIBI and, after 16 h fasting, 18F-FDG/PET metabolic scintigraphy. Wall motion impairment was either decreased or completely reversed by CABG in 95% of the asynergic segments which exhibited 18F-FDG uptake, whereas it was unmodified in 80% of the asynergic segments with no 18F-FDG uptake. A stepwise multiple logistic analysis was carried out on the asynergic segments to estimate the postoperative probability of wall motion improvement on the basis of the preoperative regional perfusion and metabolic scores. The segments with the highest probability (96%) of functional recovery from preoperative asynergy after revascularization were those with a marked 18F-FDG uptake prior to CABG. High probabilities of functional recovery were also estimated for the segments presenting with moderate and low 18F-FDG uptake (92% and 79%, respectively). A low probability of functional recovery (13%) was estimated in the segments with no 18F-FDG uptake.(ABSTRACT TRUNCATED AT 250 WORDS)