[Magnetic resonance in the tunnel carpal syndrome. Possibilities and perspectives of an etiopathogenetic study].

Thirty-four selected patients were evaluated in order to define MRI capabilities in the preoperative evaluation and characterization of the pathogenetic patterns of carpal tunnel syndrome (CTS). MRI examinations were performed by means of a superconductive unit (1.0 T, Magnetom): SE T1 (500/17) and T2 (2000/90) axial images of the carpal region were obtained with a round surface coil. In 8 patients 3D GE (FLASH) pulse sequences were used to obtain 32 images of the hand; 3D reconstruction was also applied. Six patients with rheumatoid arthritis and amyloidosis were also studied after i.v. injection of Gd-DTPA (0.2 mM/kg). MRI findings were compared with both clinico-electrophysiologic and surgical results. High agreement was observed only between MRI and surgical findings. MRI allowed the direct demonstration of carpal tunnel abnormalities in 8 cases, while abnormal findings in the median nerve were observed in 18 patients. The possibility of depicting medial nerve lesions on T2-weighted images when no direct demonstration of the cause of compression is possible, could represent a guideline for the etiopathogenetic investigation of CTS. However, further experience in selected patients is necessary to define all the aspects relative to this very common syndrome.