Increased uptake of iodine-123-BMIPP in chronic ischemic heart disease: comparison with fluorine-18-FDG SPECT.

Abstract

To evaluate the potential role of 15-p-[123I]iodophenyl-3-(R,S)-methylpentadecanoic acid (BMIPP) for the assessment of myocardial viability, the patterns of BMIPP versus 18F-fluorodeoxyglucose (FDG) uptake were evaluated in patients with chronic ischemic heart disease. Twenty-one patients with stable chronic coronary artery disease underwent resting TI SPECT to delineate myocardial perfusion followed by FDG SPECT to detect residual viability in regions showing perfusion defects. Resting BMIPP SPECT was obtained on a separate day. SPECT images were displayed as polar maps (13 segments) and analyzed semiquantitatively. A total of 273 segments were analyzed. In 87 (32%) of the segments, a perfusion defect was observed. In perfusion defects, the distributions of BMIPP/TI (mis)matches were significantly different (p < 0.0001) between the FDG viable (n = 42) and nonviable (n = 45) segments. A BMIPP/TI mismatch (BMIPP uptake higher than perfusion) was found in 74% of FDG viable segments, whereas a BMIPP/TI match (BMIPP uptake equal or lower than perfusion) was found in 69% of FDG nonviable segments. Agreement between matching or mismatching of segments was assessed to be 71%. Agreement was 81% when the data were analyzed on a patient basis. The observed frequency of BMIPP/TI mismatches was significantly higher (p < 0.05) in segments with an old myocardial infarction (20 of 36; 55%) than it was in subacute infarcted myocardium (5 of 21; 24%). In chronically hypoperfused myocardium, an increased BMIPP uptake relative to perfusion was detected, which is different from the decreased BMIPP uptake often reported in (sub)acute myocardial ischemia. Therefore, the interval from infarction may be an important factor in the interpretation of BMIPP scintigraphic data. Increased BMIPP uptake was associated with FDG/TI mismatches and may, therefore, confirm myocardial viability. Some segments with a FDG/TI mismatch, however, revealed a BMIPP/TI match. These segments may contain viable but more severely damaged tissue. Further studies on functional recovery are warranted to assess the significance of a BMIPP/perfusion (mis)match for tissue viability.