title: Magnetic resonance imaging compared with electrodiagnostic studies in patients with suspected carpal tunnel syndrome: predicting symptoms, function, and surgical benefit at 1 year.
abstract: OBJECTIVE
  The goal in this study of patients with clinical carpal tunnel syndrome (CTS) was to compare the usefulness of magnetic resonance (MR) imaging with that of electrodiagnostic studies (EDSs) for the following purposes: 1) prediction of 1-year outcomes and 2) identification of patients who are likely to benefit from surgical treatment.
  
  
  METHODS
  The authors prospectively enrolled 120 patients with clinically suspected CTS. The participants were tested using standardized EDSs, MR imaging, and a battery of questionnaires, including the Carpal Tunnel Syndrome Assessment Questionnaire, a well-validated 5-point score of symptoms and function. The EDSs and MR images were each interpreted independently. Patients were reevaluated after 1 year. The decision to treat patients conservatively or by carpal tunnel release was made by the individual surgeon, who had access to the initial EDS but not MR imaging results. Univariate and multivariate analyses were used to determine associations between 1-year outcomes and baseline diagnostic tests.
  
  
  RESULTS
  The authors recontacted 105 of 120 participants at 12 months. Of these, 30 patients had had surgery and 75 had not. Patients who had undergone surgery showed greater improvement at 1 year than those who had not had surgery. The length of the abnormal T2-weighted nerve signal on MR imaging and median-ulnar sensory latency difference were the strongest predictors of surgical benefit. There was a clear patient preference for the MR imaging over EDSs.
  
  
  CONCLUSIONS
  The findings obtained with MR imaging of the carpal tunnel predict surgical benefit independently of nerve conduction studies.
authors.affiliation: Department of Radiology, University of Washington, Seattle, WA 98195, USA. jarvikj@u.washington.edu
authors.forename: Jeffrey G
authors.initials: JG
authors.lastname: Jarvik
authors.forename: Bryan A
authors.initials: BA
authors.lastname: Comstock
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Heagerty
authors.forename: David R
authors.initials: DR
authors.lastname: Haynor
authors.forename: Deborah
authors.initials: D
authors.lastname: Fulton-Kehoe
authors.forename: Michel
authors.initials: M
authors.lastname: Kliot
authors.forename: Gary M
authors.initials: GM
authors.lastname: Franklin
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002349:Carpal Tunnel Syndrome / Q000150:complications / Q000175:diagnosis* / Q000601:surgery*; D004568:Electrodiagnosis; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008475:Median Nerve / Q000503:physiopathology*; D008875:Middle Aged; D009431:Neural Conduction / Q000502:physiology*; D011237:Predictive Value of Tests; D011930:Reaction Time / Q000502:physiology; D020127:Recovery of Function / Q000502:physiology; D016896:Treatment Outcome; D014459:Ulnar Nerve / Q000503:physiopathology