title: Ulnar neuropathy at the elbow: MR neurography--nerve T2 signal increase and caliber.
abstract: OBJECTIVE
  To assess nerve T2 signal and caliber as diagnostic signs at magnetic resonance (MR) neurography in ulnar neuropathy at the elbow (UNE).
  
  
  METHODS
  This prospective study was approved by the institutional review board, and written informed consent was obtained from all participants. Twenty patients with UNE were graded by using clinical criteria and nerve conduction studies as mild (n = 12) and severe (n = 8) and were compared with 20 healthy control subjects. All subjects underwent ulnar nerve MR neurography (in-plane resolution of 0.4 × 0.4 mm) covering the elbow region, including T2-weighted imaging with fat suppression (turbo inversion-recovery magnitude sequence: repetition time msec/echo time msec/inversion time msec, 6, 120/66/180) and T1-weighted turbo spin-echo imaging (843/16). Nerve T2 signal increase, measured by using T2-weighted contrast-to-noise ratios across the cubital tunnel, and nerve caliber, determined by using T1-weighted pixelwise measurement of cross-sectional nerve area, were evaluated as diagnostic signs. Qualitative assessment by using visual grading was performed additionally.
  
  
  RESULTS
  Diagnostic performance, as determined with area under the receiver operating characteristic curve (AUC), was excellent for nerve T2 signal to discriminate UNE from a normal finding (AUC = 0.94; 95% confidence interval [CI]: 0.87, 1.00) and was excellent for nerve caliber to discriminate severe from mild UNE (AUC = 0.95; 95% CI: 0.85, 1.00). Qualitative assessment demonstrated sensitivity of 83% and specificity of 85% for MR neurography of UNE.
  
  
  CONCLUSIONS
  Nerve T2 signal increase seems to be an accurate sign to determine the presence of UNE. Nerve caliber enlargement discriminates severe from mild UNE. UNE may be diagnosed with high accuracy by means of quantitative or qualitative evaluation of these signs.
authors.affiliation: Department of Neuroradiology, University of Heidelberg, Im Neuenheimer Feld 400, 69120 Heidelberg, Germany. philipp.baeumer@med.uni-heidelberg.de
authors.forename: Philipp
authors.initials: P
authors.lastname: Bäumer
authors.forename: Thomas
authors.initials: T
authors.lastname: Dombert
authors.forename: Frank
authors.initials: F
authors.lastname: Staub
authors.forename: Thorsten
authors.initials: T
authors.lastname: Kaestel
authors.forename: Andreas J
authors.initials: AJ
authors.lastname: Bartsch
authors.forename: Sabine
authors.initials: S
authors.lastname: Heiland
authors.forename: Martin
authors.initials: M
authors.lastname: Bendszus
authors.forename: Mirko
authors.initials: M
authors.lastname: Pham
mesh_terms: D000328:Adult; D000368:Aged; D004550:Elbow / Q000294:innervation* / Q000473:pathology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014459:Ulnar Nerve / Q000473:pathology*; D020424:Ulnar Neuropathies / Q000473:pathology*; D055815:Young Adult