Renata La Rocca Vieira MD, Presenter: Nothing to Disclose

Ronald Steven Adler MD, PhD, Abstract Co-Author: Nothing to Disclose

Kiril Kiprovski, Abstract Co-Author: Nothing to Disclose

James S. Babb PhD, Abstract Co-Author: Nothing to Disclose

Carpal tunnel syndrome (CTS) is caused by compression or irritation of the median nerve (MN) within the carpal tunnel (CT). The diagnosis of CTS might be challenging given the lack of typical clinical or EMG findings. We aim to prospectively determine whether shear wave analysis provides useful adjunctive and quantitative information regarding the diagnosis of CTS

This prospective work in progress included 5 patients-10 wrists (5 F, age range 41-70y, mean 55.6y) with clinically proven CTS and 4 healthy volunteer- 8 wrists (4 f, age range 32-45y, mean 39y). In both groups, the following measurements were performed: MN cross-sectional areas (CSA) in the CT and in the pronator quadratus (PQ); shear wave velocities in the longitudinal and axial planes (SWV) for MN and CT tendons. The differences between CTS patients and controls with regards to MN CSA and MN and tendon velocities were assessed with 9MHz linear transducer and S3000 scanner (Siemens, Mountainview, CA). A 2-dimension parametric SWV image was generated, from which selective SWV could be calculated

The CSA in the patients with CTS was significantly higher than those in the volunteers (p<0.001). In the CTS group, the difference between MN CSA in CT and PQ was significant (p=0.006). The tendon velocity was significantly higher in the CTS group compared to controls, in both axial (P <0.017) and longitudinal (p< 0.001) planes. No significant difference was found between the velocities of the MN in any plane between CTS and volunteers. The mean velocities/SD of the MN in the axial and longitudinal planes in the CTS group and volunteers are respectively 6.13/2.55 and 7.97/2.12 and 7.21/1.67 and 7.59/0.83. The difference between the velocities of the MN in the longitudinal versus axial planes is significant (p=0.011) in the CTS group

The stiffness of the CT tendons is significantly higher in patients with CTS. Preliminary data did not find significant difference between the velocities of the MN between CTS and volunteers, likely due to small sample size. Interestingly, the difference between the velocities of the MN in the longitudinal versus axial planes is significant probably due to anisotropy

The pathophysiology of CTS is a combination of increased CT pressure and ischemic injury in the MN. Our results suggest the same theory can be applied to the tendons in the CT in patients with CTS

Vieira, R, Adler, R, Kiprovski, K, Babb, J, Evaluation of the Median Nerve and Carpal Tunnel Tendons in Patients with Carpal Tunnel Syndrome using Transient Elastography.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14007451.html