急性闭合性大白兔阴囊损伤模型的建立及常规超声和超声造影评价

Establishment of an animal model of blunt scrotal trauma and evaluation of the lesion by conventional and contrast-enhanced ultrasonography

目的：建立一种阴囊急性闭合性损伤动物模型的实验方法，并利用常规超声和超声造影技术评价该损伤类型。方法：健康新西兰雄性大白兔21只，随机选择一侧阴囊，用0．5kg铁球从30cm处自由落体打击被选一侧阴囊，打击次数3～12次。利用常规超声及超声造影技术评价实验动物造模结果，并用病理结果分析验证该技术评价的准确性。结果：21例阴囊损伤造模均成功，其中挫伤10例、血肿6例、破裂5例，所有类型均经病理结果证实。常规超声能观察睾丸形态、回声改变及血流状态，但对6h以上睾丸挫伤诊断率较低，对复杂损伤不能进行准确甄别。超声造影在挫伤组表现为造影剂快速进入，各时间点造影参数到达时间（AT）、达峰时间（1TrP）与健侧比较均有统计学意义（P均〈0．05），但峰值减半时间（HT）无统计学差异（P〉0．05）；血肿组造影能清楚勾勒出血肿的轮廓，血肿周围形成延迟低增强带，造影参数AT、1_rP与健侧比较均有统计学意义；严重的睾丸破裂可以观察到睾丸内无造影剂充盈，偶可发现造影剂外溢现象。结论：铁球作多次自由落体运动打击大白兔阴囊可以建立阴囊闭合性损伤模型，〈6次的打击造成单纯挫伤型损伤的可能性较大，〉10次的打击多造成复杂多样的损伤。联合使用常规超声及超声造影技术可以提高对损伤类型的判断。

Objective： To establish an animal model of acute blunt scrotal trauma （BST） and evaluate the types of lesion by conventional ultrasonography （CUS） and contrastenhanced ultrasonography （CEUS）. Methods： We made acute BST models in 2l healthy male New Zealand rabbits by striking 3 - 12 times the unilateral testes randomly selected with a 0.5 kg iron ball falling freely from a 30 cm height. Then we evaluated the lesion types in the models by CUS and CEUS and verified our evaluation against pathological results. Results： Acute BST models were successfully established in all the 21 animals, including contusion in 10, hematoma in 6, and rupture in 5, all confirmed by pathology. CUS clearly manifested the morphology, internal echoes, and blood flow of the testes, but had a low rate of accurate diagnosis in testicular contusion for over 6 hours as well as in complex lesions. CEUS revealed an earlier perfusion of the contrast agent and shorter arriving time （AT） and time to peak intensity （TTP） in testicular contusion than in the control testes （ P 〈 0.05 ） , but showed no statistically significant difference between the two groups in the half time of descending peak intensity （P 〉 0.05）. For testicular hematoma, contrast agent clearly presented its outline and a delayed low enhancement in the surrounding tissue, with significant differences from the control in AT and TIP. In severe testis rupture, occasional outflow but no perfusion of contrast agent was observed. Conclusion ： BST models can be established in rabbits by repeated strikes of the unilateral testes with a freely falling iron ball. Simple contusion injury can be induced by less than 6 strikes, while complex injuries can be inflicted by more than 10. Combined application of CUS and CEUS can improve the accuracy of diagnosis of different types of lesion.