%0 Journal Article
%T Time-division multiplexing (TDM) sequence removes bias in T2 estimation and relaxation-diffusion measurements.
%A Liu Q
%A Gagoski B
%A Shaik IA
%A Westin CF
%A Wilde EA
%A Schneider W
%A Bilgic B
%A Grissom W
%A Nielsen JF
%A Zaitsev M
%A Rathi Y
%A Ning L
%J bioRxiv
%V 0
%N 0
%D 2024 Jun 3
%M 38895252
暂无%R 10.1101/2024.06.03.597138
%X <B>UNASSIGNED: </B>To compare the performance of multi-echo (ME) and time-division multiplexing (TDM) sequences for accelerated relaxation-diffusion MRI (rdMRI) acquisition and to examine their reliability in estimating accurate rdMRI microstructure measures.<BR><B>UNASSIGNED: </B>The ME, TDM, and the reference single-echo (SE) sequences with six echo times (TE) were implemented using Pulseq with single-band (SB-) and multi-band 2 (MB2-) acceleration factors. On a diffusion phantom, the image intensities of the three sequences were compared, and the differences were quantified using the normalized root mean squared error (NRMSE). For the in-vivo brain scan, besides the image intensity comparison and T2-estimates, different methods were used to assess sequence-related effects on microstructure estimation, including the relaxation diffusion imaging moment (REDIM) and the maximum-entropy relaxation diffusion distribution (MaxEnt-RDD).<BR><B>UNASSIGNED: </B>TDM performance was similar to the gold standard SE acquisition, whereas ME showed greater biases (3-4× larger NRMSEs for phantom, 2× for in-vivo). T2 values obtained from TDM closely matched SE, whereas ME sequences underestimated the T2 relaxation time. TDM provided similar diffusion and relaxation parameters as SE using REDIM, whereas SB-ME exhibited a 60% larger bias in the <R2> map and on average 3.5× larger bias in the covariance between relaxation-diffusion coefficients.<BR><B>UNASSIGNED: </B>Our analysis demonstrates that TDM provides a more accurate estimation of relaxation-diffusion measurements while accelerating the acquisitions by a factor of 2 to 3.