PRECISION OF MYOCARDIAL CONTOUR ESTIMATION FROM TAGGED MR-IMAGES WITHA BLACK-BLOOD TECHNIQUE

Rationale and Objectives. The authors determined whether blood presatu ration of tagged magnetic resonance (MR) images affects identification of left ventricular endocardial borders. Materials and Methods. Three healthy volunteers underwent MR imaging performed with a breath-hold segmented spoiled gradient-recalled-echo sequence with tissue tagging. Two saturation pulses (in the basal and apical regions) were used to generate black-blood images. Manual segmentation of endocardial contou rs on black-blood and white-blood images was performed independently b y five observers. Results. Endocardial borders were better identified on black-blood images compared with white-blood images, especially in the early systolic phases. Interobserver variability in contour estima tion was significantly higher for white-blood images (P < .001) and wa s twice that for corresponding black-blood images during early systole . Contour variability appeared to be affected mainly by tag-to-myocard ium contrast (P = .009) and myocardium-to-chamber contrast (P = .05). Conclusion. Blood presaturation of tagged MR images improves reliabili ty of contour segmentation.