Objective To explore the reliability of sound touch elastography measuring the elasticity of brachial plexus roots in normal adults

and to analyze their characteristics.Methods The sound touch elastography technique was used to proceed repeated measurements for the elasticity of the bilateral C5

C6 and C7 nerve roots of the 44 enrolled healthy volunteers twice in this study by one examiner.The two measurements were summarized and used for evaluation of intra-rater reliability and minimal detectable change.One of the two test results was selected randomly from all subjects

and the data were summarized and used for the analysis of relevant characteristics and influencing factors.Results The nerve root elasticity values of C5

C6 and C7 on the left and right sides of the normal adults were（2.0.64±6.87）kPa

（2.1.34±5.35）kPa

（2.5.48±7.13）kPa and（20.19±7.86） kPa

（22.35±7.99） kPa

（24.61±8.15） kPa

respectively

and the differences of both sides were not significant.Further analysis of the combination of both sides showed that the elastic values of C5

C6 and C7 were（20.41±7.34） kPa

（2.1.85±6.78）kPa

（2.5.03±7.58）kPa

respectively

which showed a significant increasing trend（P<0.01）.There were significant differences in pairs（all P<0.05）.The internal reliability of the evaluator for the C5

C6

C7 nerve root elasticity measurement in the left and right side of 44 normal adults were 0.70

0.63

0.74 and 0.68

0.60

0.71

respectively

and the corresponding minimal detectable changes were 21.01 kPa

18.16 kPa

20.02 kPa and 24.79 kPa

28.09 kPa

24.36 kPa

respectively.Conclusion Sound touch elastography has a certain reproducibility

good reliability and higher minimal detectable change in measuring the elasticity

of C5～C7 brachial plexus roots in normal adults.Possible errors in measurement should be fully considered when using this technique for quantitative assessment of disease changes or treatment efficacy.