Journal Article

MRI shows increased sciatic nerve cross sectional area in inherited and inflammatory neuropathies

Mehta, H, Reilly, M M, Yousry, T A, Cowley, P, Thornton, J S, Koltzenburg, M, Morrow, J M, Sinclair, C D J, Miranda, M A, Davagnanam, I, Hanna, M G

2011

Overview

Measurements of the cross sectional area of the sciatic nerve are described in a group of 10 patients with genetically confirmed Charcot–Marie–Tooth disease type 1A (CMT1A), nine patients with chronic inflammatory demyelinating polyneuropathy (CIDP) and 10 healthy controls using MRI. One mid-thigh of each individual was imaged using a short tau inversion recovery sequence and the nerve appearance evaluated radiologically with respect to the signal intensity and visibility of the internal neural structure. The cross sectional area of the sciatic nerve of each individual was measured by defining irregular enclosing regions of interest on the MRI images. The sciatic nerve area was enlarged in both CMT1A (p<0.001) and CIDP (p=0.008) compared with controls and in CMT1A compared with CIDP (p<0.001). Median (interquartile range) areas were 67.6 (16.2) mm2 for the CIDP group, 135.9 (46.5) mm2 for the CMT1A group and 43.3 (19.9) mm2 for the control group. The critical upper value for discriminating pathologically enlarged nerves from normal controls with p<0.05 was 64.4 mm2. Quantification of sciatic nerve hypertrophy on MRI may be of assistance in cases where the diagnosis is still in doubt, providing an objective pathological marker complimenting other clinical investigations.

• Publisher: BMJ Publishing Group Ltd,BMJ Publishing Group,BMJ Publishing Group LTD
• Subject: Adult / Aged / Ankle / Biological and medical sciences / Case-Control Studies / Charcot-Marie-Tooth Disease - genetics / Charcot-Marie-Tooth Disease - physiopathology / Cranial nerves. Peripheral nerves. Autonomic nervous system / Cranial nerves. Spinal roots. Peripheral nerves. Autonomic nervous system. Gustation. Olfaction / Female / Humans / Hypertrophy / Inflammation / Injuries of the nervous system and the skull. Diseases due to physical agents / Magnetic Resonance Imaging - methods / Male / Medical research / Medical sciences / Middle Aged / Nerve Degeneration - genetics / Nerve Degeneration - physiopathology / Nervous system (semeiology, syndromes) / Neurology / Neurosurgery / Patients / Peripheral Nervous System Diseases - genetics / Peripheral Nervous System Diseases - physiopathology / Peripheral neuropathy / Polyradiculoneuropathy, Chronic Inflammatory Demyelinating - genetics / Polyradiculoneuropathy, Chronic Inflammatory Demyelinating - physiopathology / Sciatic Nerve - pathology / Surgery (general aspects). Transplantations, organ and tissue grafts. Graft diseases / Traumas. Diseases due to physical agents