The Utility of a Combination of 99mTc-MIBI Washout Imaging and Cardiac Magnetic Resonance Imaging in the Evaluation of Cardiomyopathy

Background : In cardiomyopathy, 99m Tc-MIBI washout can reflect mitochondrial dysfunction and late gadolinium enhancement (LGE) on cardiac magnetic imaging (MRI) is associated with tissue fibrosis. We sought to determine the relationship between 99m Tc-MIBI uptake, 99m Tc-MIBI washout, and LGE on MRI in patients with cardiomyopathy. Methods : Twenty-one patients underwent rest myocardial perfusion scintigraphy at 45 minutes (early) and 4 hours (delayed) after intravenous 99m Tc-MIBI administration and cardiac MRI. We assessed myocardial perfusion, 99m Tc-MIBI washout, and LGE. We divided the left ventricle (LV) wall into 16 segments using a polar map. Then, we classified each segment into 5 groups according to 99m Tc-MIBI uptake in early-rest images and washout. Additionally, we created a contingency table based on LGE presence/absence in the groups. Results : We evaluated 336 segments in 21 patients. 99m Tc-MIBI uptake was decreased in 168 segments in the early-rest 99m Tc-MIBI images. 99m Tc-MIBI washout was observed in 108 segments with either normal perfusion or reduced perfusion in the early-rest 99m Tc-MIBI images. LGE was positive in 104 segments. A contingency table analysis with Fisher's exact test showed that LGE was observed significantly more frequently in the segments with decreased 99m Tc-MIBI uptake (p