Cervical spine MR imaging findings of patients with Hirayama disease in North America: a multisite study

Abstract

Background and purpose: Most studies of HD have been conducted in Asia, particularly Japan. To characterize the MR imaging findings of North American patients with HD, we reviewed neutral and flexion cervical MR imaging examinations performed for possible HD at 3 academic medical centers located in the Southeastern, Southwestern, and Midwestern regions of the United States.

Materials and methods: Three neuroradiologists assessed the MR imaging examinations in a blinded fashion and reached a consensus rating for LOA of the posterior dura to the spine, lower spinal cord atrophy, spinal cord T2 hyperintensity, loss of cervical lordosis, anterior dural shift with flexion, and confidence of imaging diagnosis. Final reference diagnosis was established separately with a retrospective chart review by a neurologist.

Results: Twenty-one patients met the criteria for HD, all were North American males and all who reported their race were white. Seventeen patients did not meet the criteria and served as controls. Four imaging attributes, LOA, dural shift with flexion, consensus diagnosis of neutral images, and consensus diagnosis of combined neutral and flexion images were all able to discriminate the group with HD from the group without HD (P < .05 for each). Findings of HD were often present on neutral images, but the addition of flexion images increased diagnostic confidence.

Conclusions: MR imaging findings in white North American patients with HD include LOA on neutral images and forward displacement of the dura with flexion. Findings are often present on neutral MR images and, in the appropriate clinical scenario, should prompt flexion MR imaging to evaluate anterior dural shift.

Fig 1.

An 18-year-old man with HD. A, Axial T2-weighted image demonstrates LOA at the C5 level. B, Neutral T2-weighted image demonstrates subtle atrophy at C5-C6. C, Flexion T2-weighted image demonstrates 6 mm of anterior dural shift with near-complete obliteration of the subarachnoid space at C5-C6.

Fig 2.

A 20-year-old man with HD. A, Neutral axial gradient-echo image at the C5 level demonstrates subtle bilateral LOA along the lateral aspects of the lamina bilaterally and spinal cord atrophy, asymmetric to the right. B, Neutral sagittal T2-weighted image also localizes this atrophy to C5-C6. C, Flexion sagittal T2-weighted image demonstrates 2 mm of anterior dural shift. The posterior subarachnoid space is not completely obliterated, and there is no direct spinal cord compression.