The Role of Sonoelastography in Diagnosis and Grading of Patients with Carpal Tunnel Syndrome

Abstract Background: Carpal tunnel syndrome is a result of median nerve compression by its surrounding anatomical structures. Ultrasonographic examination of the carpal tunnel can give information regarding the anatomical abnormalities of the median nerve and carpal tunnel contents, which may result in carpal tunnel syndrome. Pathophysiology of carpal tunnel syndrome can be evaluated through assessment of the elasticity of the carpal tunnel contents using sonoelastography. The two major applications in sonoelastography are strain elastography and shearwave elastography. Aim of Study: The purpose of this study was how to analyse the potential of the greyscale ultrasound, strain elastography and shearwave elastographing in diagnosing and grading carpal tunnel syndrome with the electrophysiological results used as the diagnostic reference. Patients and Methods: Grey scale ultrasound and sonoe-lastography analysis of the participants of this study was done to 100 wrists; 50 wrists (7 males and 43 females) regarded as cases and 50 normal wrists (38 males and 12 females) regarded as controls. Age range for cases was 24 to 75 years (mean of 46.32±14.29 SD). Age range for control group was 17 to 56 years (mean of 35.04±11.64 SD). Data was presented using mean and standard deviation for quantitative variables and frequency and percentage for qualitative ones. Comparison between groups for quantitative variables was performed using Independent sample test (if 2 groups) or One-way ANOVA with post-hoc Tukey's test for pairwise comparisons (if >2 groups). Association of ordinal and quantitative variables was performed through Spearman correlation coefficients. Receiver Operating Characteristics (ROC) curve analysis was conducted to explore the discriminant abilities of different nerve conduction measures to differentiate Carpal tunnel syndrome patients from controls, in addition to selection of the most appropriate cut-off points using the Youden Index (J). p-values less than or equal to 0.05 were considered statistically significant. Results: Sonoelastography parameters were able to diag-nose carpal tunnel syndrome with variably high accuracy, with strain ratio and Shearwave elastography being the most accurate of the investigated parameters. We suggested cut off values of 1.26 and 46.95 kPa for strain ratio and Shearwave elastography respectively for the diagnosis of carpal tunnel syndrome. The forementioned cut off values produced 100%, 98% sensitivities and 100%, 98% specificities for strain ratio and Shearwave elastography respectively. As for grading, cut off values for the examined parameters that accurately repre-sents the different grades of disease severity could not be established. Conclusion: Grey scale ultrasound and sonoelastography provided significant improvement in the diagnostic accuracy in the assessment of carpal tunnel syndrome. As for grading of the severity of carpal tunnel syndrome, we recommend the implementation of further studies with larger sample volume to yield better results.