title: Can ultrasound of the tibial nerve detect diabetic peripheral neuropathy? A cross-sectional study.
abstract: OBJECTIVE
  Peripheral nerve imaging by portable ultrasound (US) may serve as a noninvasive and lower-cost alternative to nerve conduction studies (NCS) for diagnosis and staging of diabetic sensorimotor polyneuropathy (DSP). We aimed to examine the association between the size of the posterior tibial nerve (PTN) and the presence and severity of DSP.
  
  
  METHODS
  We performed a cross-sectional study of 98 consecutive diabetic patients classified by NCS as subjects with DSP or control subjects. Severity was determined using the Toronto Clinical Neuropathy Score. A masked expert sonographer measured the cross-sectional area (CSA) of the PTN at 1, 3, and 5 cm proximal to the medial malleolus.
  
  
  RESULTS
  Fifty-five patients had DSP. The mean CSA of the PTN in DSP compared with control subjects at distances of 1 (23.03 vs. 17.72 mm(2); P = 0.004), 3 (22.59 vs. 17.69 mm(2); P < 0.0001), and 5 cm (22.05 vs. 17.25 mm(2); P = 0.0005) proximal to the medial malleolus was significantly larger. Although the area under the curve (AUC) for CSA measurements at all three anatomical levels was similar, the CSA measured at 3 cm above the medial malleolus had an optimal threshold value for identification of DSP (19.01 mm(2)) with a sensitivity of 0.69 and a specificity of 0.77 by AUC analysis.
  
  
  CONCLUSIONS
  This large study of diabetic patients confirms that the CSA of the PTN is larger in patients with DSP than in control subjects, and US is a promising point-of-care screening tool for DSP.
authors.affiliation: Department of Anesthesia, University Health Network and University of Toronto, Toronto, Ontario, Canada.
authors.forename: Sheila
authors.initials: S
authors.lastname: Riazi
authors.forename: Vera
authors.initials: V
authors.lastname: Bril
authors.forename: Bruce A
authors.initials: BA
authors.lastname: Perkins
authors.forename: Sherif
authors.initials: S
authors.lastname: Abbas
authors.forename: Vincent W S
authors.initials: VW
authors.lastname: Chan
authors.forename: Mylan
authors.initials: M
authors.lastname: Ngo
authors.forename: Leif E
authors.initials: LE
authors.lastname: Lovblom
authors.forename: Hossam
authors.initials: H
authors.lastname: El-Beheiry
authors.forename: Richard
authors.initials: R
authors.lastname: Brull
mesh_terms: D000368:Aged; D003430:Cross-Sectional Studies; D003929:Diabetic Neuropathies / Q000175:diagnosis* / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D013979:Tibial Nerve / Q000000981:diagnostic imaging* / Q000473:pathology*; D014463:Ultrasonography