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Direct diffusion tensor estimation using a model‐based method with spatial and parametric constraints
Author(s) -
Zhu Yanjie,
Peng Xi,
Wu Yin,
Wu Ed X.,
Ying Leslie,
Liu Xin,
Zheng Hairong,
Liang Dong
Publication year - 2017
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1002/mp.12054
Subject(s) - diffusion mri , acceleration , imaging phantom , parametric statistics , tensor (intrinsic definition) , computer science , mathematics , conjugate gradient method , algorithm , magnetic resonance imaging , physics , statistics , geometry , medicine , classical mechanics , optics , radiology
Purpose To develop a new model‐based method with spatial and parametric constraints ( MB ‐ SPC ) aimed at accelerating diffusion tensor imaging ( DTI ) by directly estimating the diffusion tensor from highly undersampled k ‐space data. Methods The MB ‐ SPC method effectively incorporates the prior information on the joint sparsity of different diffusion‐weighted images using an L1–L2 norm and the smoothness of the diffusion tensor using a total variation seminorm. The undersampled k ‐space datasets were obtained from fully sampled DTI datasets of a simulated phantom and an ex‐vivo experimental rat heart with acceleration factors ranging from 2 to 4. The diffusion tensor was directly reconstructed by solving a minimization problem with a nonlinear conjugate gradient descent algorithm. The reconstruction performance was quantitatively assessed using the normalized root mean square error ( nRMSE ) of the DTI indices. Results The MB ‐ SPC method achieves acceptable DTI measures at an acceleration factor up to 4. Experimental results demonstrate that the proposed method can estimate the diffusion tensor more accurately than most existing methods operating at higher net acceleration factors. Conclusion The proposed method can significantly reduce artifact, particularly at higher acceleration factors or lower SNR s. This method can easily be adapted to MR relaxometry parameter mapping and is thus useful in the characterization of biological tissue such as nerves, muscle, and heart tissue.