Experimental study on contrast-enhanced ultrasound to evaluate testicular microvascular injury

Objective To explore the way of contrast-enhanced ultrasound(CEUS) and quantitative analysis technology to assess testicular microvascular ischemia-reperfusion injury. Methods Twenty-four healthy adult rabbits were randomly divided into the control group and the microvascular mild, moderate, serve ischemic injury group (group Ⅰ, including group Ⅰ1, Ⅰ2, Ⅰ3). The spermatic cord of the control group were threaded but not ligated. The group Ⅰ1, Ⅰ2, Ⅰ3 were reperfused 2 h after 2 h, 4 h, 6 h complete testicular ischemia respectively. The ultrasound contrast angiographic parameters of each group were analyzed by the quantitative analysis techniques, including peak intensity(PI), time to peak(TP), slope, mean transmit time(MTT), DT/2 and area. The levels of plasma vWF, NO and ET-1 were tested after the CEUS. The pathological changes of the ipsilateral testicular were observed by the HE and immunohistochemical staining. Statistical analysis was performed by SPSS13.0 software. Results Preoperativeiy, each parameter of the experimental group and the control group showed no statistical significance (P>0.05). Postoperatively, the PI, slope, area of the group Ⅰ1 increased significantly, while the TP, MTT were prolonged(P<0.05). Contrast time-intensity curve was significantly higher peak and retrusion. The group Ⅰ2′s PI, slope, area increased further, DT/2 was significantly prolonged, but TP significantly reduced(P<0.05). The contrast curve significantly increased, forward and decreased slowly. The contrast curves of the group Ⅰ3 was approximate a straight line. The vWF, NO, ET-1 levels of each experimental group were significantly higher than those in control group (P<0.05), among them, the levels of group Ⅰ2 were the highest(P<0.05). With the aggravation of ischemia, the testicular capillaries expansion, erythrocyte sedimentation, leakage, infiltration of inflammatory cells, MMP-9 expression in vascular basement membrane gradually increased. Conclusions The CEUS and quantitative analysis techniques can effectively evaluate testicular microvascular injury. Key words: Ultrasonography; Microbubbles; Testis; Ischemia; Reperfusion injury