title: 3-T high-resolution MR neurography of sciatic neuropathy.
abstract: OBJECTIVE
  The sciatic nerve may normally exhibit mild T2 hyperintensity in MR neurography (MRN) images, rendering assessment of sciatic neuropathy difficult. The purpose of this case-control study was to evaluate whether a quantitative and qualitative analysis of the sciatic nerves and regional skeletal muscles increases the accuracy of MRN in detecting sciatic neuropathy.
  
  
  METHODS
  We retrospectively reviewed the MRN studies of the pelvis and thighs of 34 subjects (12 men and 22 women; mean [± SD] age, 50 ± 15 years), of which 17 had a final diagnosis of sciatic neuropathy according to electrodiagnostic or surgical confirmation, and 17 had no evidence of sciatic neuropathy and served as control subjects. On each side, the sciatic nerves were evaluated for signal intensity (SI), size, course, and fascicular shape, whereas the regional skeletal muscles were evaluated for edema, fatty replacement, and atrophy. In addition, the nerve-to-vessel SI ratio was registered for each side at the same time and 8 months later.
  
  
  RESULTS
  The sciatic nerves of the abnormal sides exhibited higher nerve-to-vessel SI ratios and higher incidences of T2 hyperintensity, enlargement, and abnormal fascicular shape compared to the nerves of the normal sides. The regional muscles of the abnormal sides demonstrated a higher grade of fatty infiltration and higher frequencies of edema and atrophy. A cutoff value of nerve-to-vessel SI ratio of 0.89 exhibited high sensitivity and specificity in predicting sciatic neuropathy. Calculation of the nerve-to-vessel SI ratio demonstrated excellent inter- and intraobserver reliability.
  
  
  CONCLUSIONS
  Both qualitative and quantitative criteria should be used to suggest the MRN diagnosis of sciatic neuropathy.
authors.affiliation: Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins Hospital, Baltimore, MD 21287, USA. achhabr6@jhmi.edu
authors.forename: Avneesh
authors.initials: A
authors.lastname: Chhabra
authors.forename: Majid
authors.initials: M
authors.lastname: Chalian
authors.forename: Theodoros
authors.initials: T
authors.lastname: Soldatos
authors.forename: Gustav
authors.initials: G
authors.lastname: Andreisek
authors.forename: Neda
authors.initials: N
authors.lastname: Faridian-Aragh
authors.forename: Eric
authors.initials: E
authors.lastname: Williams
authors.forename: Allan J
authors.initials: AJ
authors.lastname: Belzberg
authors.forename: John A
authors.initials: JA
authors.lastname: Carrino
mesh_terms: D016022:Case-Control Studies; D016009:Chi-Square Distribution; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D012189:Retrospective Studies; D020426:Sciatic Neuropathy / Q000473:pathology*; D012680:Sensitivity and Specificity; D018709:Statistics, Nonparametric