Contrast-enhanced Ultrasound For Evaluation Of Acute Renal Trauma: An Experimental Study

ObjectiveThe purpose of this study was to assess the value of contrast-enhanced ultrasonography (CEUS) in detection of acute renal trauma in rabbits.Materials and methods41 healthy adult New Zealand white rabbits were randomly divided into two groups: the acute renal injury group (n=18) and the acute renal injury with active hemorrhage group (n=23). Under general anesthesia, a laparotomy was performed on each animal to expose the kidney, In the acute renal injury group, 32 blunt and penetrating injuries of grade â…  ~ â…£ were created by bumping the kidney with a weight or puncturing the kidney with a radiofrequency needle;In the acute renal injury with active hemorrhage group, after the animals were heparinized, 46 penetrating renal injuries of grade â…¢ and â…£ with active hemorrhage were created by puncturing the kidney with a radiofrequency needle. Conventional ultrasonography and CEUS were performed with a Sequioa 512 scanner (Siemens Medical Solutions, Mountain View, CA) before and after all the animal acute renal trauma models were created. After the experiment was finished, the animals were sacrificed and the renal specimens were obtained for pathologic examination. The results of conventional ultrasonography and CEUS were compared with pathological findings.Results1. The acute renal trauma groupThe results showed that CEUS can visualize the site, shape and area of renalinjury and hematoma more clearly than conventional ultrasonography;the sensitivity and specificity of CEUS and conventional ultrasonography in the diagnosis of acute renal trauma were 94.4 % ^ 83.3 % and 63.9% ? 52.8% respectively. There was a significant difference between the two(P < 0.01).2. The acute renal injury with active hemorrhage groupAfter the injection of contrast agent, the active bleeding was showed as the contrast agent microbubbles overflowing from injured renal blood vessels and then forming abnormal irregular enhanced regions. The sensitivity of this imaging feature was 100%. Conventional ultrasonography can not demonstrate the active bleeding reliably. Through the time-intensity quantitative analysis, it has been showed that the intensity of the bleeding area within the kidney was significantly higher than that of the normal renal parenchyma for average 85s after the injection of contrast agent (P < 0.01).ConclusionsCEUS can improve the diagnostic accuracy of ultrasonography in acute renal trauma and evaluate the degree of renal injury effectively;the real-time imaging can visualize the active hemorrhage clearly;quantitative analysis of CEUS can also help to evaluate the abnormal blood infusion within the injury region.