PURPOSE: To evaluate the accuracy of ultrasonography (US) in the diagnosis of @entity923 ( @entity923 ) in @entity1 with a bifid median nerve on the basis of cross-sectional area ( @entity10002 ) measurements of the median nerve at the level of the @entity923 (CSAc), with additional measurements obtained more proximally ( @entity10002 ) at the level of the pronator quadratus muscle. MATERIALS AND METHODS: This HIPAA-compliant study was approved by the local institutional review board; informed oral and written consent were obtained. Fifty-three wrists in 49 consecutive @entity1 with a bifid median nerve and @entity923 symptoms and 28 wrists in 27 healthy volunteers with a bifid median nerve were examined by using US. Two independent US examiners who were blinded to prior test results measured median nerve @entity10002 at two levels, CSAc and @entity10002 . The difference between CSAc and @entity10002 (/\ @entity10002 ) was calculated for each wrist. Receiver operating characteristic (ROC) analysis was performed. RESULTS: The study population included 17 @entity1 and 32 @entity1 (mean age, 55.1 years; age range, 24-78 years). The control population included 13 @entity1 and 14 @entity1 (mean age, 52.6 years; age range, 24-86 years). Mean CSAc was approximately 5 mm(2) greater in @entity1 with @entity923 than in healthy volunteers (P < .0001), while mean /\ @entity10002 was 5.8-5.9 mm(2) greater in @entity1 with @entity923 (P < .0001). A CSAc threshold of 12 mm(2) provided sensitivity and specificity of 84.9% and 46.5%, respectively, while a /\ @entity10002 threshold of 4 mm(2) provided sensitivity and specificity of 92.5% and 94.6%, respectively. ROC analysis demonstrated a significant advantage of /\ @entity10002 (area under ROC curve [A(z)] = 0.95-0.96) compared with CSAc (A(z) = 0.84-0.85) for the diagnosis of @entity923 (P < .003). CONCLUSION: The use of a /\ @entity10002 parameter improves the diagnostic accuracy of US for the presence of @entity923 in @entity1 with a bifid median nerve.

Bifid median nerve in XXXX : assessment with US cross-sectional area measurement.

@entity923 :: ('MESH:D002349', 'Disease') :: ['carpal tunnel', 'CTS', 'carpal tunnel syndrome'] @entity1 :: ('9606', 'Species') :: ['women', 'patients', 'men'] @entity10002 :: ('1161', 'Gene') :: ['CSA', 'CSAp']
@entity923 :: (MESH:D002349,Disease) :: ['carpal tunnel syndrome']
