Impaired myocardial fatty acid metabolism detected by 123I-BMIPP in patients with unstable angina pectoris: comparison with perfusion imaging by 99mTc-sestamibi.

The present study was undertaken to determine the potential diagnostic value of 123I-BMIPP scintigraphy for the detection of altered myocardial fatty acid metabolism in patients with unstable angina. Both myocardial metabolic imaging with 123I-BMIPP and perfusion imaging with 99mTc-sestamibi were performed at rest in 28 patients with unstable angina in the pain-free state. The regional uptakes of 123I-BMIPP or 99mTc-sestamibi were scored semiquantitatively (0 = normal, 4 = no activity) and compared with the coronary arteriographic findings. Decreased uptakes of 123I-BMIPP were observed in 18 patients, and 11 patients had abnormal 99mTc-sestamibi images. Defect scores of 123I-BMIPP were larger than those of 99mTc-sestamibi (7.8 +/- 2.1 vs. 5.2 +/- 1.9, p < 0.01). The sensitivity for the detection of patients with unstable angina was higher in 123I-BMIPP than in 99mTc-sestamibi (77% vs. 45%, p < 0.01). The site of the decreased 123I-BMIPP uptake corresponded to the most stenotic coronary artery lesion in all patients. Fatty acid metabolic imaging with 123I-BMIPP was more sensitive for detecting myocardial ischemia than perfusion imaging with 99mTc-sestamibi. 123I-BMIPP may be a clue to define the culprit lesion in unstable angina and be helpful to decide the best treatment and guide coronary angioplasty.