Preliminary Application Of Three-dimensional Ultrasound In The Diagnosis Of Carpal Tunnel Syndrome

Objective:The aim of study was to assess the immaging charateristics and the usefulness of three-dimensional ultrasound(3DUS) in the diagnosis of carpal tunnel syndrome. Comparing the feature of 3D ultrasonography wit h 2D ultrasonography. Methods:39 patients with carpal tunnel syndrome confirmed by electromyography and 30 healthy control participants underwent 3DUS of the wrists. The patients were classified into mild(seventeen wrists),moderate(nineteen wrists) and severe group(t wenty-four wrists) according to the clinical classification and treatment programs proposed by Gu Yudong.The thickness of transverse carpal ligament and cross-sectional area of median nerve at the hamate hook level and peas bone level were measured by 2D ultrasonography, The thickness of transverse carpal ligament and volume of median nerve were measured by 3D ultrasonography.Data from the patient group and control group were compared to determine the statistical significance.The accuracy of the ultrasonographic diagnostic diagnostic criteria for carpal tunnel syndrome was evaluated using receiver operating characteristic(ROC) analysis. Analysising and comparing the image feature of 3D ultrasonography with 2D ultrasonography. Results:The examination of 2D ultrasonography:The thickness of transverse carpal ligament at the peas bone level in CTS patients(0.437±0.107)cm is higher than HC group(0.320±0.171)cm,the difference was statistically significant(p<0.05). The moderate CTS group and moderate-severe CTS group were(0.341±0.128)cm and(0.532±0.153)cm, the difference was statistically significant(p<0.05).The thickness of transverse carpal ligament at the hamate hook level in CTS patients(0.506±0.183)cm is higher than HC group(0.375±0.119)cm, the difference was statistically significant(p<0.05). The moderate CTS group and moderate-severe CTS group were(0.397±0.173)cm and(0.613±0.200)cm, the difference was statistically significant(p<0.05).The cross-sectional area of median nerve at the hamate hook level in CTS patients(0.161±0.027)cm2 is higher than HC group(0.129±0.082)cm2,the difference was statistically significant(p<0.05). The moderate CTS group and moderate-severe CTS group were(0.143±0.051)cm2 and(0.179±0.014)cm2, the difference was statistically significant(p<0.05).The cross-sectional area of median nerve at the peas bone level in CTS patients(0.103±0.021)cm2 is higher than HC group(0.079±0.013)cm2,the difference was statistically significant(p<0.05). The moderate CTS group a nd moderate-severe CTS group were(0.086±0.017)cm2 and(0.120±0.011)cm2, the difference was statistically significant(p<0.05).Comparing the data of CTS group with CH group, The threshold of thickness of transverse carpal ligament at the peas bone level is 0.337 cm,the diagnostic accuracy is 67%,the diagnostic sensitivity is 77.3%.The cross-sectional area of median nerve at the peas bone level is 0.139cm2,the diagnostic accuracy is 91.7%,the diagnostic sensitivity is 93.1%;The threshold of thickness of transverse carpal ligament at the hamate hook level is 0.408 cm,the diagnostic accuracy is 72.4%,the diagnostic sensitivity is 61.2%.The cross-sectional area of median nerve at the hamate hook level is 0.087cm2,the diagnostic accuracy is 87.7%,the diagnostic sensitivity is 82%.Comparing the data of moderate CTS group and moderate-severe CTS group, The threshold of thickness of transverse carpal ligament at the peas bone level is 0.418 cm,the diagnostic accuracy is 82.7%,the diagnostic sensitivity is 77.3%. The cross-sectional area of median nerve at the peas bone level is 0.151cm2,the diagnostic accuracy is 92.6 %,the diagnostic sensitivity is 90.0%; The threshold of thickness of transverse carpal ligament at the hamate hook level is 0.441 cm,the diagnostic accuracy is 74.1%,the diagnostic sensitivity is 66%. The cross-sectional area of median nerve at the hamate hook level is 0.100cm2,the diagnostic accuracy is 86.1%,the diagnostic sensitivity is 84.3%.The examination of 3D ultrasonography: The volume of median nerve at the peas bone level of the distal 1.5 cm in CTS patients(0.151±0.045)cm3is higher than HC group(0.112±0.0043)cm3,the difference was statistically significant(p<0.05). The moderate CTS group and moderate-severe CTS group were(0.132 ± 0.014) cm3and(0.169 ± 0.081) cm3cm2, the difference was statistically significant(p<0.05).Comparing the data of CTS group with CH group,The threshold of volume of median nerve at the peas bone level is 0.139cm3,the diagnostic accuracy is 94.7%,the diagnostic sensitivity is 89.5%. Comparing the data of moderate CTS group and severe CTS group, The threshold of volume of median nerve at the peas bone level is 0.130cm3,the diagnostic accuracy is 92.8%,the diagnostic sensitivity is 94.0%.The thickness of transverse carpal ligament and the cross-sectional area of median nerve at several levels can be detected through changing location and method of measurement by 2D ultrasonography.In most cases,the hook of the hamate bone was compressed.Another common site was the pisiform bone.Sometimes both two sites could be compressed at the same time.The length of compressed nerve was not the same.The median nerve is obvious flattening in deep hamate hook and is significant thickering at the peas bone level, the cross-sectional area is biggest at the peas bone level. The images are more intuitive by 3D ultrasonography,which can clearly show the shape, size and adjacent relationship of median nerve, flexor tendons and other contents of the carpal tunnel, nerve entrapment that usually show volume increases.The volume is bigger at nerve entrapment. Conclusion:High-frequency ultrasound examination is a valuable and partical tool in the diagnostic,sererity and clinical classification of carpal tunnel syndrome,it is simple,reliable and atraumatic. 3D ultrasonography is more easier,which can provide three-dimensional image at the lesion comparing with 2D ultrasonography and has great clinical value and potential applications.