The application of three-dimensional diffusion-weighted PSIF technique in peripheral nerve imaging of the distal extremities

Purpose: To evaluate whether the addition of the three-dimensional diffusion-weighted reversed fast imaging with steady state free precession (3D DW-PSIF) sequence improves the identification of peripheral nerves in the distal extremities. Materials and Methods: Twelve MR neurography (MRN) studies of the distal upper extremity and 12 MRN studies of distal lower extremity were evaluated. From the 24 subjects who were enrolled, 10 had clinically suspected peripheral neuropathy, whereas 14 suffered from various orthopedic diseases and had no clinical signs of neuropathy. In each examination, the ability to identify each peripheral nerve on T2-weighted and 3D DW-PSIF sequences was evaluated using a semi-quantitative (0-2) scale. Thereafter, a total certainty score was registered for each sequence. Results: Combining the results of all studies, the mean certainty score was 1.92 ± 0.28 on the 3D DW-PSIF images and 1.50 ± 0.72 on the T2-weighted images (P < 0.001). In the upper extremity studies, the corresponding certainty scores were 2.0 and 1.70 ± 0.55, respectively (P = 0.008), and in the lower extremity studies, 1.86 ± 0.35 and 1.36 ± 0.79, respectively (P < 0.001). Conclusion: The 3D DW-PSIF images provide improved identification of the nerves compared with the T2-weighted images, and should be incorporated in the MRN protocol, whenever accurate nerve localization and/or presurgical evaluation are required.