Muscle crush injury of extremity:quantitative elastography with supersonic shear imaging

Objective To explore the appearance of muscle crush injury at quantitative ultrasonographic elastography by supersonic shear imaging (SSI).Methods The animal experiment was done using a special balloon cuff device to create left hind leg crush injury with a force of 18.6 kPa.Twentythree New Zealand rabbits had crush injury of extremity and survived for 72 hours.SSI quantitative elastography was performed in crushed and no-crushed regions of each rabbit hind leg.Quantitative lesion elasticity was measured in terms of the Young modulus (in kilopascals) at 30 min,2 h,6 h,24 h and 72 h after the release of the crushing pressure.A receiver operating characteristic (ROC) curve analysis was used to assess diagnostic performance.Results The area of crushed region in left hind leg accounted for 2.6％ -3.0％ of body surface area in 23 rabbits.The crushed regions exhibited maximum elasticity values of (19.51 ± 6.74)kPa,(21.47 ± 5.54) Pa,(11.36 ± 5.35)kPa,(15.09 ± 3.31)kPa and (13.72 ± 3.74) kPa,and mean elasticity values of (12.44 ± 3.77)kPa,(13.20 ± 3.60)kPa,(6.80±2.86)kPa,(10.04 ± 2.95)kPa and (6.94 ± 0.97)kPa at 30 min,2 h,6 h,24 h and 72 h after the release of the crushing pressure.Comparing with those of no-crushed regions,they were higher obviously (P＜0.001).ROC curves showed that extremity crush injury was diagnosed by using elasticity value,and the greater the elasticity value,the greater the diagnostic value.Conclusions SSI provides quantitative elasticity measurements,thus adding complementary information that potentially could help in crush injury characterization with conventional ultrasonography. Key words: Uhrasonography; Muscle injury; Crush injury; Supersonic shear imaging