Deep Learning Constrained Compressed Sensing Reconstruction Improves High-Resolution 3D T2-weighted Turbo Spin Echo MRI of the Lumbar Spine

Objective We sought to assess the image quality of 3D T2-weighted (w) Turbo Spin Echo (TSE) sequences with Deep Learning (DL) constrained Compressed Sensing (CS) reconstruction relative to a reference 2D T2w TSE sequence for routine clinical lumbar spine MRI. Materials and Methods 53 patients underwent imaging of the lumbar spine with a sagittal 2D T2w TSE sequence and with two CS accelerated 3D T2w TSE sequences (voxel size of 0.4x0.4 × 0.5 mm) with CS factors of 7 and 11. The CS accelerated sequences were reconstructed with iterative reconstruction with wavelet transformation (conventional CS) and secondly with a DL constrained CS reconstruction (named CS-AI). Two readers graded image quality, based on 8 metrics (overall image quality, presence of image noise, presence of motion artifacts, delineation/conspicuity and clarity of anatomical structures as spinal cord, cauda equine nerve roots, cerebrospinal fluid CSF, intervertebral disc, bone marrow and intervertebral foramen) using Likert scales. Results Overall interreadout agreement was substantial (Krippendorff's alpha = 0.724, 95%CI: 0.692-0.755). The CS7-AI and CS11-AI sequences were comparable or better than the 2D sequence in all 8 metrics (p<0.001-p>0.99). The CS7 and CS11 sequences were comparable or better than the 2D sequence in only 5 and 3 of 8 metrics respectively (p<0.001-p>0.99). Conclusion A DL constrained CS reconstruction significantly improves the quality of accelerated high-resolution 3D T2w TSE imaging of the lumbar spine. Thus, high quality imaging in sub-millimeter resolution in all three imaging planes can be achieved without compromising the image quality as compared with standard 2D T2w TSE imaging.