Diagnosing ulnar neuropathy at the elbow using magnetic resonance neurography.

INTRODUCTION: Early diagnosis of ulnar neuropathy at the elbow is important. Magnetic resonance neurography (MRN) images peripheral nerves. We evaluated the usefulness of elbow MRN in diagnosing ulnar neuropathy at the elbow.

METHODS: The MR neurograms of 21 patients with ulnar neuropathy were reviewed retrospectively. MRN was performed prospectively on 10 normal volunteers. The MR neurograms included axial T1 and axial T2 fat-saturated and/or axial STIR sequences. The sensitivity and specificity of MRN in detecting ulnar neuropathy were determined.

RESULTS: The mean ulnar nerve size in the symptomatic and normal groups was 0.12 and 0.06 cm(2) (P < 0.001). The mean relative signal intensity in the symptomatic and normal groups was 2.7 and 1.4 (P < 0.01). When using a size of 0.08 cm(2), sensitivity was 95% and specificity was 80%.

DISCUSSION: Ulnar nerve size and signal intensity were greater in patients with ulnar neuropathy. MRN is a useful test in evaluating ulnar neuropathy at the elbow.