title: Cervical spine MR imaging findings of patients with Hirayama disease in North America: a multisite study.
abstract: OBJECTIVE
  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.
  
  
  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.
authors.affiliation: Division of Neuroradiology, Department of Radiology, Mayo Clinic College of Graduate Medical Education, Rochester, Minnesota 55905, USA. lehman.vance@mayo.edu
authors.forename: V T
authors.initials: VT
authors.lastname: Lehman
authors.forename: P H
authors.initials: PH
authors.lastname: Luetmer
authors.forename: E J
authors.initials: EJ
authors.lastname: Sorenson
authors.forename: R E
authors.initials: RE
authors.lastname: Carter
authors.forename: V
authors.initials: V
authors.lastname: Gupta
authors.forename: G P
authors.initials: GP
authors.lastname: Fletcher
authors.forename: L S
authors.initials: LS
authors.lastname: Hu
authors.forename: A L
authors.initials: AL
authors.lastname: Kotsenas
mesh_terms: D000293:Adolescent; D000328:Adult; D001284:Atrophy; D002574:Cervical Vertebrae; D005188:False Negative Reactions; D006801:Humans; D008141:Lordosis / Q000473:pathology; D008279:Magnetic Resonance Imaging / Q000379:methods* / Q000592:standards / Q000706:statistics & numerical data; D008297:Male; D008875:Middle Aged; D015146:Midwestern United States; D015588:Observer Variation; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D015144:Southeastern United States; D015206:Southwestern United States; D013116:Spinal Cord / Q000473:pathology*; D014897:Spinal Muscular Atrophies of Childhood / Q000473:pathology*; D055815:Young Adult