FIGURE 8:

Representative T₂ maps estimated from different reconstruction methods at R = 5 using an eight-echo spin-echo T₂ mapping sequence (GE 3T Signa Excite Hdx), respectively, for a symptomatic patient. The global low rank (GLR) reconstruction generated images with noticeable artifacts in bone and fatty tissues (white arrows). Although the local low rank (LLR) reconstruction improved overall image quality with reduced image artifacts, it led to noticeable smoothing due to the exploitation of local sparsity at high acceleration. In contrast, model-augmented neural network with incoherent k-space sampling (MANTIS) generated nearly artifact-free T₂ maps with well-preserved sharpness and texture comparable to the reference T₂ maps. This qualitative observation was also confirmed using the residual error maps (displayed with the same scale) and nRMSE values. Images courtesy Dr. Fang Liu, University of Wisconsin, Madison, WI.