Background-Late-gadolinium-enhanced (LGE) cardiac MRI (CMR) is a powerful method for characterizing myocardial infarction (MI), but the requisite gadolinium infusion is estimated to be contraindicated in ≈20% of patients with MI because of end-stage chronic kidney disease. The purpose of this study is to investigate whether T1 CMR obtained without contrast agents at 3 T could be an alternative to LGE CMR for characterizing chronic MIs using a canine model of MI. Methods and Results-Canines (n=29) underwent CMR at 7 days (acute MI [AMI]) and 4 months (chronic MI [CMI]) after MI. Infarct location, size, and transmurality measured by using native T1 maps and LGE images at 1.5 T and 3 T were compared. Resolution of edema between AMI and CMI was examined with T2 maps. T1 maps overestimated infarct size and transmurality relative to LGE images in AMI (P=0.016 and P=0.007, respectively), which was not observed in CMI (P=0.49 and P=0.81, respectively) at 3 T. T1 maps underestimated infarct size and transmurality relative to LGE images in AMI and CMI (P1 of the infarcted myocardium was increased in CMI and AMI (P2 of the infarcted myocardium was increased in AMI (P0.20) at both feld strengths. Histology showed extensive replacement fbrosis within the CMI territories. CMI detection sensitivity and specifcity of T1 CMR at 3 T were 95% and 97%, respectively. Conclusions-Native T1 maps at 3 T can determine the location, size, and transmurality of CMI with high diagnostic accuracy. Patient studies are necessary for clinical translation.
- Myocardial infarction
ASJC Scopus subject areas
- Cardiology and Cardiovascular Medicine
- Radiology Nuclear Medicine and imaging