Current T(1) and T(2) mapping techniques applied with simple thresholds cannot discriminate acute from chronic myocadial infarction on an individual patient basis: a pilot study

BACKGROUND: Studying T(1)- and T(2)-mapping for discrimination of acute from chronic myocardial infarction (AMI, CMI). METHODS: Eight patients with AMI underwent CMR at 3 T acutely and after >3 months. Imaging techniques included: T(2)-weighted imaging, late enhancement (LGE), T(2)-mapping, native and post-contrast T(1)-mapping. Myocardial T(2)- and T(1)-relaxation times were determined for every voxel. Abnormal voxels as defined by having T(2)- and T(1)-values beyond a predefined threshold (T(2) > 50 ms, native T(1) > 1250 ms and post-contrast T(1) < 350 ms) were highlighted and compared with LGE as the reference. RESULTS: Abnormal T(2)-relaxation times were present in the voxels with AMI (=> delete acute infarction; unfortunately this is not possible in your web interface) acute infarction only in half of the subjects. Abnormal T(2)-values were also present in subjects with CMI, thereby matching the chronically infarcted territory in some. Abnormal native T(1) times were present in voxels with AMI in 5/8 subjects, but also remote from the infarcted territory in four. In CMI, abnormal native T(1) values corresponded with infarcted voxels, but were also abnormal remote from the infarcted territory. Voxels with abnormal post-contrast T(1)-relaxation times agreed well with LGE in AMI and CMI. CONCLUSIONS: In this pilot-study, T(2)- and T(1)-mapping with simple thresholds did not facilitate the discrimination of AMI and CMI.