Three-dimensional simultaneous brain T , T , and ADC mapping with MR Multitasking.

Purpose: To develop a simultaneous T , T , and ADC mapping method that provides co-registered, distortion-free images and enables multiparametric quantification of 3D brain coverage in a clinically feasible scan time with the MR Multitasking framework.

Methods: The T /T /diffusion weighting was generated by a series of T preparations and diffusion preparations. The underlying multidimensional image containing 3 spatial dimensions, 1 T weighting dimension, 1 T -preparation duration dimension, 1 b-value dimension, and 1 diffusion direction dimension was modeled as a 5-way low-rank tensor. A separate real-time low-rank model incorporating time-resolved phase correction was also used to compensate for both inter-shot and intra-shot phase inconsistency induced by physiological motion. The proposed method was validated on both phantom and 16 healthy subjects. The quantification of T /T /ADC was evaluated for each case. Three post-surgery brain tumor patients were scanned for demonstration of clinical feasibility.

Results: Multitasking T /T /ADC maps were perfectly co-registered and free from image distortion. Phantom studies showed substantial quantitative agreement ( ) with reference protocols for T /T /ADC. In vivo studies showed nonsignificant T (P = .248), T (P = .97), ADC (P = .328) differences among the frontal, parietal, and occipital regions. Although Multitasking showed significant differences of T (P = .03), T (P < .001), and ADC (P = .001) biases against the references, the mean bias estimates were small (ΔT % < 5%, ΔT % < 7%, ΔADC% < 5%), with all intraclass correlation coefficients greater than 0.82 indicating "excellent" agreement. Patient studies showed that Multitasking T /T /ADC maps were consistent with the clinical qualitative images.

Conclusion: The Multitasking approach simultaneously quantifies T /T /ADC with substantial agreement with the references and is promising for clinical applications.