Comparison of Perfusion-Metabolism Mismatch in 99mTc-MIBI and 123I-BMIPP Scintigraphy With Cardiac Magnetic Resonance in Patients With Dilated Cardiomyopathy

Abstract

BackgroundCardiac magnetic resonance (CMR) imaging is an established method of detecting myocardial fibrosis related to prognosis in patients with dilated cardiomyopathy (DCM). Recent studies have found that 99mTc–methoxy-isobutyl-isonitrile (MIBI) and 123I–15-(p-iodophenyl)-3(R,S)-methylpentadecanoic acid (BMIPP) dual single-photon-emission computerized tomography (MIBI-BMIPP dual SPECT) can detect perfusion-metabolism mismatches. We compared MIBI-BMIPP dual SPECT with CMR findings and assessed their prognostic abilities to determine the significance of abnormal metabolism in patients with DCM. Methods and ResultsFifty inpatients with DCM (age 58 ± 12 y; 14 female) were assessed with the use of MIBI-BMIPP dual SPECT and CMR. Perfusion-metabolism mismatches were identified mainly at the left ventricular free wall, whereas late gadolinium enhancement (LGE) was evident mostly at the septal wall. During a median follow-up of 33 months, 9 patients developed cardiac events including death, heart failure, and fatal arrhythmia. Event-free survival rates were significantly lower for patients with LGE plus a mismatch than with other abnormalities (P = .001). Among clinical and imaging variables, LGE plus a mismatch was significantly associated with cardiac events (hazard ratio 7.9, 95% confidence interval 1.8–35.6; P = .007). ConclusionsCoexisting LGE and a perfusion-metabolism mismatch accurately predict future cardiac events in patients with DCM.