[Novel Application of Post-contrast T₁map for Detection of Subendocardial Infarction]

In cardiac magnetic resonance (CMR) for myocardial infarction, there have been quite a few cases of obscure image contrast between subendocardial lesion and left ventricular (LV) blood pool on late gadolinium enhancement (LGE) images. This study was motivated by confirmation of usefulness of post-contrast T₁map for detection of subendocardial infarction. From June 2017 to May 2018, forty-eight consecutive patients who underwent contrast-enhanced CMR to assess myocardial infarction were reviewed. We measured the contrast ratio (CR) between the infarcted myocardium and LV blood pool on LGE and on post-contrast T₁map images, and compared them. The CR (mean±standard deviation) was -0.04±0.11 for LGE images and 0.02±0.04 for post-contrast T₁map images (P<0.05). These results suggest that the post-contrast T₁map, which uses the difference in T₁ value as image contrast rather than magnitude image, can clearly depict the boundary between the infarcted myocardium and LV blood pool. The addition of post-contrast T₁map to image interpretation might provide valuable information in the evaluation of subendocardial infarction.