Three-dimensional quantitative T-1 and T-2 mapping of the carotid artery: Sequence design and in vivo feasibility

PurposeA novel three-dimensional (3D) T-1 and T-2 mapping protocol for the carotid artery is presented. MethodsA 3D black-blood imaging sequence was adapted allowing carotid T-1 and T-2 mapping using multiple flip angles and echo time (TE) preparation times. B-1 mapping was performed to correct for spatially varying deviations from the nominal flip angle. The protocol was optimized using simulations and phantom experiments. In vivo scans were performed on six healthy volunteers in two sessions, and in a patient with advanced atherosclerosis. Compensation for patient motion was achieved by 3D registration of the inter/intrasession scans. Subsequently, T-1 and T-2 maps were obtained by maximum likelihood estimation. ResultsSimulations and phantom experiments showed that the bias in T-1 and T-2 estimation was<10% within the range of physiological values. In vivo T-1 and T-2 values for carotid vessel wall were 84496 and 39 +/- 5 ms, with good repeatability across scans. Patient data revealed altered T-1 and T-2 values in regions of atherosclerotic plaque. ConclusionThe 3D T-1 and T-2 mapping of the carotid artery is feasible using variable flip angle and variable TE preparation acquisitions. We foresee application of this technique for plaque characterization and monitoring plaque progression in atherosclerotic patients. Magn Reson Med 75:1008-1017, 2016. (c) 2015 Wiley Periodicals, Inc.