MAGNETIC-RESONANCE NEUROGRAPHY OF PERIPHERAL-NERVE LESIONS IN THE LOWER-EXTREMITY

OBJECTIVE: We describe the clinical application and utility of high-re solution magnetic resonance neurography (MRN) techniques to image the normal fascicular structure of peripheral nerves and its distortion by mass lesions or trauma in the lower extremity. METHODS: MRN images we re obtained using a standard 1.5 Tesla magnet and custom built phased- array coils. Patients were imaged using T1-weighted spin echo without and with gadolinium, T2-weighted fast spin echo with fat suppression, and short tau inversion recovery fast spin-echo pulse sequences. Nine patients were studied, four with peripheral nerve tumors (three neurof ibromas and one schwannoma), two with intraneural cysts, and three wit h traumatic peripheral nerve lesions. Six patients with peripheral ner ve mass lesions underwent surgery, thereby allowing MRN images to be c orrelated with intraoperative and pathological findings. RESULTS: Preo perative MRN accurately imaged the normal fascicular anatomy of periph eral nerves and precisely depicted its relation to tumor and cystic le sions. Increased signal on TZ-weighted fast spin-echo and short tau in version recovery fast spin-echo pulse sequences was seen in the periph eral nerve fascicles of patients with clinical and electrodiagnostic e vidence of nerve injury. CONCLUSION: MRN proved useful in the preopera tive evaluation and planning of surgery in patients with peripheral ne rve lesions.