title: Spinal Diffusion Tensor Imaging in Evaluation of Preoperative and Postoperative Severity of Cervical Spondylotic Myelopathy: Systematic Review of Literature.
abstract: BACKGROUND
  Diffusion tensor imaging (DTI) is increasingly investigated as a potential diagnostic and prognostic tool for symptomatic degenerative cervical pathology; however, it is yet to be validated for this purpose.
  
  
  OBJECTIVE
  To investigate the association of preoperative DTI signal changes and postoperative outcomes in patients with cervical spondylotic myelopathy (CSM).
  
  
  METHODS
  We performed a systematic literature review using PubMed for clinical studies using DTI in adults undergoing operative management for CSM. Data on preoperative clinical status, preoperative DTI metrics, and postoperative clinical outcomes were abstracted. Preoperative DTI parameters were correlated with preoperative severity and postoperative outcomes and pooled across studies.
  
  
  RESULTS
  Nine studies met inclusion criteria for 238 patients who underwent operative management with mean follow-up time 310 days. Higher preoperative fractional anisotropy (FA) at the level of maximal compression correlates strongly with a higher preoperative modified Japanese Orthopaedic Association (mJOA) score (n = 192 patients, rho = 0.62, P < 0.001). Higher preoperative FA is associated with less postoperative mJOA change (n = 27, rho = -0.42, P = 0.02) but a greater recovery rate (n = 93, rho = 0.32, P < 0.001). Preoperative FA correlated with lower Neck Disability Index (n = 15, rho = -0.61, P = 0.04). Preoperative fiber tract ratio had a large positive correlation with a postoperative recovery rate (n = 20, rho = 0.61, P = 0.005). When reported, an apparent diffusion coefficient showed an inverse correlation compared with FA.
  
  
  CONCLUSIONS
  DTI is associated with preoperative severity and postoperative outcomes in CSM patients, suggesting that DTI may become useful in identifying those most likely to benefit from operative intervention (Level 3 Evidence). Prospective trials with standardized DTI acquisition techniques and patient selection are required for higher-level evidence.
authors.affiliation: Department of Neurological Surgery, Emory University School of Medicine, Atlanta, Georgia, USA.
authors.forename: Rima S
authors.initials: RS
authors.lastname: Rindler
authors.affiliation: Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, Georgia, USA.
authors.forename: Falgun H
authors.initials: FH
authors.lastname: Chokshi
authors.affiliation: Department of Neurological Surgery, Emory University School of Medicine, Atlanta, Georgia, USA.
authors.forename: James G
authors.initials: JG
authors.lastname: Malcolm
authors.affiliation: Department of Neurological Surgery, Emory University School of Medicine, Atlanta, Georgia, USA.
authors.forename: Sheila R
authors.initials: SR
authors.lastname: Eshraghi
authors.affiliation: Department of Radiology, University of Washington, Seattle, Washington, USA.
authors.forename: Mahmud
authors.initials: M
authors.lastname: Mossa-Basha
authors.affiliation: Department of Neurological Surgery, Emory University School of Medicine, Atlanta, Georgia, USA.
authors.forename: Jason K
authors.initials: JK
authors.lastname: Chu
authors.affiliation: Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, Wisconsin, USA.
authors.forename: Shekar N
authors.initials: SN
authors.lastname: Kurpad
authors.affiliation: Department of Neurological Surgery, Emory University School of Medicine, Atlanta, Georgia, USA. Electronic address: faiz.ahmad@emory.edu.
authors.forename: Faiz U
authors.initials: FU
authors.lastname: Ahmad
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D056324:Diffusion Tensor Imaging / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011182:Postoperative Care / Q000706:statistics & numerical data*; D011300:Preoperative Care / Q000706:statistics & numerical data*; D015995:Prevalence; D011379:Prognosis; D015203:Reproducibility of Results; D012307:Risk Factors; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D017678:Sex Distribution; D013116:Spinal Cord / Q000000981:diagnostic imaging; D055009:Spondylosis / Q000000981:diagnostic imaging* / Q000453:epidemiology / Q000601:surgery*; D016896:Treatment Outcome
keywords: Cervical spondylotic myelopathy; Diffusion tensor imaging; Modified Japanese Orthopaedic Score; Neck Disability Index; Spinal cord