肺栓塞螺旋CT扫描技术的探讨

Spiral CT scan technique in imaging the pulmonary embolism

目的通过总结肺栓塞螺旋CT扫描技术,以掌握单螺旋CT扫描最佳参数。方法分析15例临床拟诊肺栓塞患者的螺旋CT扫描参数,包括层厚2～3mm,螺距2.0,造影剂为非离子型对比剂100ml,注射速度2.5～3.5ml/s,增强延迟时间12～18s,扫描方向从足侧向头侧,扫描范围从膈上2～3cm至主动脉弓上缘。结果15例病人中显示肺栓塞9例,肺动脉主干栓塞6例,段动脉栓塞2例,亚段肺动脉段栓塞1例。肺栓塞的螺旋CT直接征象为肺动脉腔内充盈缺损;间接征象为“马赛克”征及肺梗死灶等。结论螺旋CT诊断肺栓塞已得到公认,而正确选择扫描技术参数,是肺栓塞螺旋CT扫描成功的关键,也是能否进行正确诊断的依据。

Objective To summarize optimal spiral CT scan protocol in imaging the pulmonary embolism（PE） Methods The spiral CT scan protocol was analyzed in 15 cases of suspected PE, in which the scan parameters included 2-3ram slice thickness, pitch 2.0, flow rate at 2.5-3.5ml/s, and 12 - 18s delay scan time. Acquisition was triggered caudocephalad from 2-3mm above diaphragm to aortic arch after the administration of 100ml non-ionic contrast-medium. Results PE were visualized in 9 cases of 15, including emboli found in main pulmonary arteries in 6 cases; in segmental arteries in 2; and in sub-segmental artery in 1 case. The direct spiral CT finding of PE was intra-luminal filling defects in pulmonary arteries. The secondary CT findings included ＂mosaic sign＂ and pulmonary infarction. Conclusion The value of spiral CT in diagnosis of PE has already been recognized. Appropriate protocol is the key for successful imaging and essential for an accurate diagnosis.