title: Accuracy of ultrasonography and magnetic resonance imaging in diagnosing carpal tunnel syndrome using rest and grasp positions of the hands.
abstract: OBJECTIVE
  To compare the accuracy of ultrasonography and magnetic resonance imaging (MRI) in diagnosing carpal tunnel syndrome (CTS) in both the rest and grasp positions. We postulated that the diagnostic accuracy could be improved by imaging hands in the grasp position rather than in the rest position.
  
  
  METHODS
  Fifty patients with CTS and 45 healthy volunteers received a package of questionnaires and had a physical examination and a nerve conduction study. Ultrasonography and MRI images were recorded in both the rest and grasp positions for each participant.
  
  
  RESULTS
  There were significant differences between the patients and the healthy volunteers regarding patient-reported outcomes, the results of physical examinations, the nerve conduction studies, and the ultrasonography and MRI imaging. The area under the receiver operating characteristic curve of ultrasonography was significantly improved by measuring the bowing of the flexor retinaculum in the grasp position than by measuring that in the rest position. The diagnostic accuracy of ultrasonography was similar to that of MRI when we used a combination of the measurements of the cross-sectional area of the median nerve in the rest position and the bowing of the flexor retinaculum in the grasp position.
  
  
  CONCLUSIONS
  The accuracies of MRI and ultrasonography for diagnosing CTS were improved by measuring the bowing of the flexor retinaculum in the grasp position. Ultrasonography can be an adequate screening method for CTS if clinicians combine the cross-sectional area of the median nerve in the rest position and the bowing of the flexor retinaculum in the grasp position.
  
  
  METHODS
  Diagnostic I.
authors: Department of Physical Medicine and Rehabilitation, Buddhist Tzu Chi General Hospital, Taipei Branch, Taiwan.
authors: Yi-Shiung
authors: YS
authors: Horng
authors: Hsu-Chao
authors: HC
authors: Chang
authors: Kun-Eng
authors: KE
authors: Lin
authors: Yue-Liang
authors: YL
authors: Guo
authors: Dung-Huan
authors: DH
authors: Liu
authors: Jung-Der
authors: JD
authors: Wang
mesh_terms: D019540:Area Under Curve; D002349:Carpal Tunnel Syndrome / Q000175:diagnosis* / Q000000981:diagnostic imaging; D016022:Case-Control Studies; D004185:Disability Evaluation; D005260:Female; D006225:Hand / Q000000981:diagnostic imaging; D018737:Hand Strength; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008475:Median Nerve / Q000000981:diagnostic imaging; D008875:Middle Aged; D009431:Neural Conduction; D010147:Pain Measurement; D010808:Physical Examination; D012372:ROC Curve; D012146:Rest; D011795:Surveys and Questionnaires; D014463:Ultrasonography