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 ^99mTcsestamibi 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.