Simultaneous visualization of nerves and vessels of the lower extremities using magnetization-prepared susceptibility weighted magnetic resonance imaging at 3.0 T

BACKGROUND: Identifying the extent of involvement of the vessel and nerve, particularly in regard to preoperative evaluation and precise localization of the tumor and its relation to the structures of the extremities, has important applications for advancing the treatment of lower extremity diseases. OBJECTIVE: To review the technical feasibility of simultaneous visualization of nerves and vessels of the lower extremities by using magnetization-prepared susceptibilityweighted magnetic resonance (MR) imaging (MP-SWI) at 3.0T. METHODS: Ten healthy volunteers and 10 patients were studied. Optimized MP-SWI, MR neurography (MRN) based on 3D diffusion-weighted steady-state free precession imaging and contrast-enhanced MR angiography (CE-MRA) sequences were performed for each subject. The means of signal-to-noise ratio (SNR)n, SNRv, SNRm, contrastto- noise ratio (CNR)_n,m and CNR_v,m were calculated and the certainty of identifying nerves and vessels was determined. CNR_n,m between MP-SWI and MRN, and CNR_v,m between MP-SWI and CE-MRA were compared. RESULTS: MP-SWI provides slightly poorer CNR_v,m than CE-MRA, whereas MP-SWI provides a better CNR_n,m than MRN. In thin-slice-thickness maximum-intensity projection arbitrary planes, the sciatic nerve and its branches were clearly identified (score 1 or 2 of 2) in 17 subjects (85%); the femoral artery and the main branches were identified (score 1 or 2 of 2) in all 20 subjects (100%). The nerves are isointense to slightly hypointense to muscle, and the vessels show a more obvious hyperintense signal than muscle in MP-SWI. CONCLUSION: The proposed MP-SWI demonstrates the feasibility of simultaneously visualizing nerves and vessels of the lower extremities without using an exogenous contrast agent. It may enable straightforward localization of a disease process to a specific nerve and vessel.