LOCALIZATION OF ISCHEMIA IN CANINE HEARTS USING TAGGED ROTATED LONG AXIS MR-IMAGES, ENDOCARDIAL SURFACE STRETCH AND WALL THICKENING

Tagged magnetic resonance imaging allows the noninvasive measurement o f regional systolic myocardial deformations and helps localize ischemi c regions in the left ventricle (LV). The objective of this study was to evaluate the potential accuracy of localizing ischemic regions in t he LV using endocardial and epicardial data obtained from tagged rotat ed long axis images, Nine canine hearts with acute ischemia induced by coronary artery ligation were imaged along four long axis planes rota ted around the LV long axis, at end diastole and end systole, Each pla ne was tagged by four parallel lines perpendicular to the LV long axis , Tracing the endocardial and epicardial intersection points of the ta g lines, 24 myocardial cuboids were reconstructed for each LV at end d iastole and end systole. Endocardial surface stretch and transmural sy stolic thickening were calculated for each cuboid, The functional data were compared to perfusion data obtained from postmortem monastral bl ue staining of the heart, The ability of each functional index to disc riminate between ischemic and non-ischemic regions was assessed using the ''t''-statistic. The potential accuracy in localizing ischemia was evaluated by studying the corresponding sensitivity-specificity curve s. The results demonstrate that adequate discrimination and localizati on can be obtained with both functional indices, However, endocardial surface stretch is advantageous as it uses only endocardial data and c an save 50% of the post-processing time. (C) 1997 Elsevier Science Inc .