Three‐dimensional whole‐heart T 2 mapping at 3T

Purpose Detecting 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. Methods The 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. Results Homogeneous three‐dimensional (3D) T 2 maps were obtained from normal human subjects and swine. Normal human and swine left ventricular T 2 values were 42.3 ± 4.0 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. Conclusion Free‐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. © 2014 Wiley Periodicals, Inc.