64层螺旋CT对兔慢性肺小动脉栓塞诊断的实验研究

The Study of 64 Slices Spiral CT Angiography of Chronic Small Pulmonary Artery Thromboembolism Model in Rabbits

目的建立兔的慢性肺小动脉血栓栓塞模型,研究其64层CT肺动脉造影(CTPA)表现和诊断价值。材料与方法健康家兔8只,体重2.0～2.5kg。对栓塞前、后肺动脉造影和CT表现进行对比。栓塞组兔肺动脉多次注入经热处理的自体血栓,血栓直径1～2mm,长3～5mm,栓塞前、后和12周时行64层螺旋CT平扫和CTPA,分析其影像学表现特点。结果 8只兔对比栓塞前后CTPA影像发现栓塞血管共43支,其中血管直径为1.5～2.0mm7支,1.0～1.5mm8支,0.5～1.0mm共17支,<0.5mm者共11支。未对比栓塞前影像共发现直径<2.0mm的肺动脉栓塞31支,其中血管直径1.5～2.0mm7支(阳性率100%),1.0～1.5mm7支(阳性率87.5%),0.5～1.0mm12支(阳性率70.6%),<0.5mm5支(阳性率45.5%)。假栓塞组术前、后和12周以后CTPA均未发现肺动脉栓塞直接和间接征像。结论兔自体血栓反复注射法建立慢性肺小动脉栓塞模型有较高的可行性。64层螺旋CTPA对直径1mm以上级别的肺小动脉栓塞诊断阳性率高。

Objective To make a model of chronic small pulmonary artery thromboembolism in rabbits and discuss the diagnostic value of 64-slice spiral CT pulmonary angiography （CTPA）. Materials and Methods The models of pulmonary artery embolism （PE）were made by repeated injection of heat-treated autologous clot in 8 rabbits,thrombus diameter of 1-2 mm,a length of 3-5 mm. CTPA were performed before and after embolization,12 weeks later respectively. Imaging features of CT and CTPA were analyzed. Results 43 embolized pulmonary arteries of all 8 rabbits were found,diameter of 1.5-2 mm in 7 vessels,1-1.5 mm in 8 vessels,0.5-1 mm in 17 vessels,less than 0.5 mm in 11 vessels. 31 embolized small pulmonary arteries were found in CTPA before thromboembolism,of which 1.5-2 mm diameter in 7 vessels（positive rate of 100%）,1-1.5 mm in 7 vessels （positive rate 87.5%）,0.5-1 mm in 12 vessels （positive rate 70.6%）,less than 0.5 mm in 5 vessels（positive rate 45.5%）.The direct and indirect signs were not found in sham embolization group. Conclusion Repeated injection of autologous blood clot to establish chronic small pulmonary artery thromboembolism model has a high feasibility. 64-slice CTPA can be used for diagnosis of PE（vessel diameter larger than 1 mm）.