On the sampling strategies and models for measuring diffusion exchange with a double diffusion encoding sequence

查看全文 作　　者：Alfredo [1]Ordinola;Shan [2,3]Cai;Peter [2,3]Lundberg;Ruiliang [4]Bai;Evren [1,3]Ozarslan 机构地区：[1]Department of Biomedical Engineering(IMT),Link oping University,Link oping,S-58185,Sweden;[2]Department of Radiation Physics,Department of Health,Medicine and Caring Sciences(HMV),Link oping University,Link oping,S-58183,Sweden;[3]Center for Medical Image Science and Visualization(CMIV),Link oping University,Link oping,S-58185,Sweden;[4]School of Medicine,Zhejiang University,866 Yuhangtang Rd,Hangzhou,310058,China 出　　处：《Magnetic Resonance Letters》索引2023年第3卷第3期,共17页 基　　金：the Swedish Foundation for International Cooperation in Research and Higher Education(STINT),and the Swedish Research Council(Dnr 2022e04715). 摘　　要：Water exchange between the different compartments of a heterogeneous specimen can be characterized via diffusion magnetic resonance imaging(dMRI).Many analysis frameworks using dMRI data have been proposed to describe exchange,often using a double diffusion encoding(DDE)stimulated echo sequence.Techniques such as diffusion exchange weighted imaging(DEWI)and the filter exchange and rapid exchange models,use a specific subset of the full space DDE signal.In this work,a general representation of the DDE signal was employed with different sampling schemes(namely constant b1,diagonal and anti-diagonal)from the data reduction models to estimate exchange.A near-uniform sampling scheme was proposed and compared with the other sampling schemes.The filter exchange and rapid exchange models were also applied to estimate exchange with their own subsampling schemes.These subsampling schemes and models were compared on both simulated data and experimental data acquired with a benchtop MR scanner.In synthetic data,the diagonal and near-uniform sampling schemes performed the best due to the consistency of their estimates with the ground truth.In experimental data,the shifted diagonal and near-uniform sampling schemes outperformed the others,yielding the most consistent estimates with the full space estimation.The results suggest the feasibility of measuring exchange using a general representation of the DDE signal along with variable sampling schemes.In future studies,algorithms could be further developed for the optimization of sampling schemes,as well as incorporating additional properties,such as geometry and diffusion anisotropy,into exchange frameworks. 关 键 词：Diffusion MRI Water exchange Sampling schemes Double diffusion encoding