title: Significance of Intramedullary High Signal Intensity on Magnetic Resonance Imaging in Patients with Cervical Ossification of the Posterior Longitudinal Ligament.
abstract: BACKGROUND
  The purpose of this study was to analyze the relation between intramedullary high signal intensity (IMHS) on magnetic resonance imaging (MRI), radiographic parameters, and clinical symptoms in cervical ossification of the posterior longitudinal ligament (OPLL) patients.
  
  
  METHODS
  Two hundred forty-one patients, who underwent simple radiography, computed tomography (CT), and MRI were included in the present study. As radiographic parameters, the OPLL occupying ratio and occupying area were measured on CT images. Dynamic factors were assessed by measuring cervical range of motion (ROM) on simple radiographs. Visual analog scale (VAS) for neck and arm pain, and Japanese Orthopaedic Association (JOA) scores were evaluated for clinical analysis. The differences in radiographic and clinical findings were assessed between patients with IMHS on T2-weighted MRI findings (group A) and patients without IMHS (group B).
  
  
  RESULTS
  Eighty-one patients were assigned to group A and 160 patients to group B. The occupying ratios were found to be higher in group A than in group B on both sagittal and axial views (p < 0.01). Group A also showed a higher area occupying ratio (p < 0.01). The length and area of underlying spinal canal on the sagittal and cross-sectional planes were lower in group A than in group B (p < 0.01). No significant difference in ROM was observed (p = 0.63). On the clinical findings, group A had a lower JOA score (p < 0.001), and no intergroup differences in VAS scores were observed.
  
  
  CONCLUSIONS
  In cervical OPLL cases, IMHS on MRI was associated with manifestation of myelopathic symptom. Occupying ratio was associated with high signal intensity on MRI, whereas no association was found with ROM. Occurrence of high signal intensity increased inversely with the length and area of underlying spinal canal.
authors.affiliation: Department of Orthopedic Surgery, Inje University Haeundae Paik Hospital, Inje University College of Medicine, Busan, Korea.
authors.forename: Byung-Wan
authors.initials: BW
authors.lastname: Choi
authors.affiliation: Department of Orthopedic Surgery, Inje University Haeundae Paik Hospital, Inje University College of Medicine, Busan, Korea.
authors.forename: Tae Woong
authors.initials: TW
authors.lastname: Hum
mesh_terms: D000328:Adult; D000368:Aged; D002574:Cervical Vertebrae / Q000473:pathology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000145:classification*; D008297:Male; D008875:Middle Aged; D019547:Neck Pain; D017887:Ossification of Posterior Longitudinal Ligament / Q000145:classification* / Q000473:pathology*; D010147:Pain Measurement
keywords: Cervical spine; Intramedullary high signal change; Magnetic resonance imaging; Ossification of posterior longitudinal ligament