Usefulness of Tc-99m methoxyisobutylisonitrile scintigraphy for evaluating congestive heart failure

Background. Evidence is accumulating that technetium 99m methoxyisobutylisonitrile (MIBI) is not retained in the impaired myocardium. The purpose of this study was to determine whether the severity of congestive heart failure (CHF) can be evaluated by use of the washout rate (WR) of MIBI. Methods and Results. Seventeen patients with CHF and ten healthy volunteers were enrolled in this study. MIBI and iodine 123 metaiodobenzylguanidine (MIBG) scintigraphy techniques were performed, and the WR was calculated. The blood was also sampled for the measurement of levels of brain natriuretic peptide, which is a powerful predictor of the severity of CHF. The WR of MIBI was higher in CHF patients (31.2% +/- 6.3%) than in healthy volunteers (25.2% +/- 4.7%) (P < .05). There were positive correlations between the WR of MIBI and brain natriuretic peptide levels (r = 0.723, P < .0001) and a negative correlation between the WR of MIBI and the left ventricular ejection fraction (r = -0.545, P < .01). The WR of MIBT was correlated with that of MIBG (r = 0.603, P < .01). Conclusions. MIBI scintigraphy is useful in evaluating the severity of congestive heart failure.