[Value of Contrast-enhanced Ultrasound in Detection of Peripheral Nerve Crush Injury].

Objective To explore the value of contrast-enhanced ultrasound(CEUS)in the detection of peripheral nerve crush injury.Methods Thirty New Zealand white rabbits were randomly divided into normal control group and sciatic nerve crush injury group(which included 3-day,2-week,4-week,and 8-week groups after operation).The morphological structure and blood perfusion of the injured sciatic nerves were detected by high-frequency ultrasound,power Doppler ultrasound(PDUS),CEUS,and histopathology.Results Conventional ultrasound revealed that the internal diameter of nerves showed no significant difference between the 8-week group and the control group [(1.14±0.15)mm vs.(0.92±0.11)mm;t=4.72,P=0.86].Analysis of nerve blood perfusion showed that PDUS had a high sensitivity in displaying fine blood flow signal inside the injured nerve in the acute stage of inflammation(3-day group)but not good enough in the 4-and 8-week groups.CEUS could clearly show the microcirculation perfusion in the 3-day,2-week,4-week,and 8-week groups,and analyses of the area under the curve,the peak time,and the peak intensity showed that the nerve blood perfusion increased significantly 3 days after operation and then decreased gradually.Histopathological examination showed that the median cumulative OD value was 12 035.6(10 566.3,14 805.8)8 weeks after operation,which was still significantly lower than that 18 784.8(15 904.5,21 103.5)in the normal control group(H=6.10, P=0.0003).Conclusions Conventional high-frequency ultrasound and PDUS can not adequately evaluate the microcirculation perfusion in different periods after nerve injury.CEUS can quantitatively evaluate the microvascular perfusion of injured nerve at any period and provide more information for indirect evaluation of nerve regeneration.