title: Increased flow signal in compressed segments of the spinal cord in patients with cervical spondylotic myelopathy.
abstract: METHODS
  Prospective controlled trial.
  
  
  OBJECTIVE
  To describe a newly found increased flow signal in phase-contrast magnetic resonance imaging observed in compressed segments of the spinal cord in patients with cervical spondylotic myelopathy (CSM).
  
  
  BACKGROUND
  Derangement of cerebrospinal fluid movement in the spine is a well-known cause of syringomyelia. However, its possible role in CSM has not been studied well, despite the fact that similar derangement takes place in CSM.
  
  
  METHODS
  In a consecutive series of 57 patients with CSM, cardiac-gated phase-contrast magnetic resonance imaging was analyzed. The amplitude of the flow signal obtained in the compressed segment of the spinal cord was compared with that obtained in the lesion-free C2 segment. It was also compared with controls obtained from 10 healthy volunteers. We also studied whether the amplitude was correlated with the severity of cervical canal stenosis, neurological symptoms, indication of surgery, and the presence of intramedullary high-intensity signal on T2-weighted images. In 33 patients who underwent decompression surgical procedures, we compared the amplitude of the flow signal between the preoperative and the postoperative study.
  
  
  RESULTS
  Increased flow signal on phase-contrast study was seen in compressed segments of the spinal cord in 36 (63%) patients. The mean amplitude of the signal in the compressed segment was 0.64 ± 0.06 cm/s, whereas that in the C2 segment was 0.27 ± 0.01 and that in the controls was 0.28 ± 0.01. The flow signal linearly increased as the severity of canal stenosis increased. It significantly correlated with the symptom of upper-extremity dysesthesia, and the indication of surgery in these patients. The mean amplitude of the signal tended to be higher in those with intramedullary high-intensity signal than in those without. After decompression surgery, the increased flow signal was markedly diminished, and returned to a level comparable with the controls.
  
  
  CONCLUSIONS
  Phase-contrast imaging demonstrated increased flow signal in compressed segments of the spinal cord in a majority of patients with CSM. This suggests a possible role played by derangement of cerebrospinal fluid movement in CSM. It also suggests potential usefulness of phase-contrast study in the management of patients with CSM.
  
  
  METHODS
  2.
authors.affiliation: From the Department of Neurosurgery, Saitama Medical Center, Saitama Medical University, Saitama, Japan.
authors.forename: Han Soo
authors.initials: HS
authors.lastname: Chang
authors.forename: Takahide
authors.initials: T
authors.lastname: Nejo
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Yoshida
authors.forename: Soichi
authors.initials: S
authors.lastname: Oya
authors.forename: Toru
authors.initials: T
authors.lastname: Matsui
mesh_terms: D000368:Aged; D002574:Cervical Vertebrae / Q000473:pathology / Q000601:surgery; D019299:Decompression, Surgical; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011446:Prospective Studies; D013116:Spinal Cord / Q000473:pathology* / Q000601:surgery; D013117:Spinal Cord Compression / Q000473:pathology* / Q000601:surgery; D055009:Spondylosis / Q000473:pathology* / Q000601:surgery