APPLICATION OF MAGNETIC-RESONANCE NEUROGRAPHY IN THE EVALUATION OF PATIENTS WITH PERIPHERAL-NERVE PATHOLOGY

Currently, diagnosis and management of disorders involving nerves are generally undertaken without images of the nerves themselves. The auth ors evaluated whether direct nerve images obtained using the new techn ique of magnetic resonance (MR) neurography could be used to make clin ically important diagnostic distinctions that cannot be readily accomp lished using existing methods. The authors obtained T-2-weighted fast spin-echo fat-suppressed (chemical shift selection or inversion recove ry) and T-1-weighted images with planes parallel or transverse to the long axis of nerves using standard or phased-array coils in healthy vo lunteers and referred patients in 242 sessions. Longitudinal and cross -sectional fascicular images readily distinguished perineural from int raneural masses, thus predicting both resectability and requirement fo r intraoperative electrophysiological monitoring. Fascicle pattern and longitudinal anatomy firmly identified nerves and thus improved the s afety of image-guided procedures. In severe trauma, MR neurography ide ntified nerve discontinuity at the fascicular level preoperatively, th us verifying the need for surgical repair. Direct images readily demon strated increased diameter in injured nerves and showed the linear ext ent and time course of image hyperintensity associated with nerve inju ry. These findings confirm and precisely localize focal nerve compress ions, thus avoiding some exploratory surgery and allowing for smaller targeted exposures when surgery is indicated. Direct nerve imaging can demonstrate nerve continuity, distinguish intraneural from perineural masses, and localize nerve compressions prior to surgical exploration . Magnetic resonance neurography can add clinically useful diagnostic information in many situations in which physical examinations, electro diagnostic tests, and existing image techniques are inconclusive.