Comparison of contrast-enhanced MRI with iodine-123 BMIPP for detection of myocardial damage in hypertrophic cardiomyopathy

OBJECTIVE. The purpose of this study was to compare contrast-enhanced MRI with dual-radionuclide SPECT for the detection of myocardial damage associated with hypertrophic cardiomyopathy. SUBJECTS AND METHODS. Twenty-three patients with hypertrophic cardiomyopathy were examined. Delayed hyperenhancement of the damaged myocardium was observed using contrast-enhanced MRI, and regional wall thickness and left ventricular ejection fraction were measured using cine balanced steady-state free precession MRI. Dual-radionuclide SPECT using technetium-99m sestamibi and iodine-123 15-(p-iodophenyl)-3-(R,S)-methyl-pentadecanoic acid (BMIPP) was performed at rest. In the abnormal myocardial segments, agreement between the contrast-enhanced MRI and I-123 BMIPP SPECT was assessed. The relationships between the regional and global cardiac abnormalities and the delayed hyperenhancement on MRI and decreased uptake of I-123 BMIPP were also evaluated. RESULTS. In 368 left ventricular segments, 57 segments showed delayed hyperenhancement on MRI, 43 segments showed decreased uptake of I-123 BMIPP, and seven showed decreased uptake of Tc-99m sestamibi. The delayed hyperenhancement and decreased uptake of I-123 BMIPP were frequently observed in the interventricular septal wall (p < 0.0001); however, the agreement between the methods in detecting myocardial abnormalities was fair (kappa = 0.38). The abnormal septal walls were significantly thicker than those without apparent abnormalities (p = 0.031). There was an inverse correlation between the number of enhancing segments and the ejection fraction (r = -0.53). CONCLUSION. In hypertrophic cardiomyopathy, contrast-enhanced MRI was valuable for the detection of extensive myocardial damage.