Sensitivity of high-resolution ultrasonography in clinically diagnosed carpal tunnel syndrome patients with hand pain and normal nerve conduction studies.

BACKGROUND

Suspecting carpal tunnel syndrome (CTS) in patients with hand pain is usual. Considering the variable rate of false-negative results in nerve conduction study (NCS), as a frequent reference confirmatory standard test, we aimed to evaluate the diagnostic accuracy of neuromuscular ultrasound in patients with clinical evidence of CTS and normal NCS.

METHODS

It was a diagnostic accuracy study conducted in the outpatient clinic of Rofaydeh Hospital, Tehran, Iran, between July 2012 and December 2016; it recruited clinically diagnosed CTS patients and a control group. All participants underwent comprehensive clinical examination, NCS, and high-resolution ultrasonography of the median nerve.

RESULTS

Two hundred and fifty patients with clinical evidence of CTS met the inclusion criteria, of whom 103 (27.1%) had normal NCS and underwent an ultrasound examination. A cutoff point of 9.4 mm2 (mean + 2 standard deviation) for median nerve cross-sectional area at the carpal tunnel inlet from the control group was set to detect 73% abnormality in the case group.

CONCLUSION

Ultrasonography had a sensitivity rate of 73% in patients with clinical CTS and negative NCS, increasing the overall diagnostic sensitivity for clinically suspected CTS in the electrodiagnostic lab setting to 92%. The study highlights the complementary role of ultraso-nography in diagnosing CTS in conjunction with NCS.