Three-dimensional whole-heart T2 mapping at 3T.

PurposeDetecting variations in myocardial water content with T-2 mapping is superior to conventional T-2-weighted MRI since quantification enables direct observation of complicated pathology. Most commonly used T-2 mapping techniques are limited in achievable spatial and/or temporal resolution, both of which reduce accuracy due to partial-volume averaging and misregistration between images. The goal of this study was to validate a novel free breathing T-2 mapping sequence that overcomes these limitations. MethodsThe proposed technique was made insensitive to heart rate variability through the use of a saturation prepulse to reset magnetization every heartbeat. Respiratory navigator-gated, differentially T-2-weighted volumes were interleaved per heartbeat, guaranteeing registered images and robust voxel-by-voxel T-2 maps. Free breathing acquisitions removed limits on spatial resolution and allowed short diastolic windows. Accuracy was quantified with simulations and phantoms. ResultsHomogeneous three-dimensional (3D) T-2 maps were obtained from normal human subjects and swine. Normal human and swine left ventricular T-2 values were 42.34.0 and 43.5 +/- 4.3 ms, respectively. The T-2 value for edematous myocardium obtained from a swine model of acute myocardial infarction was 59.1 +/- 7.1 ms. ConclusionFree-breathing accurate 3D T-2 mapping is feasible and may be applicable in myocardial assessment in lieu of current clinical black blood, T-2-weighted techniques. Magn Reson Med 74:803-816, 2015. (c) 2014 Wiley Periodicals, Inc.