电子束CT在诊断肺动脉栓塞中的应用

Electron beam CT(EBCT): clinical application in diagnosis of pulmonary embolism

目的评价电子束ＣＴ（ＥＢＣＴ）在诊断肺动脉栓塞（ｐｕｌｍｏｎａｒｙｅｍｂｏｌｉｓｍ，ＰＥ）中的作用。方法对２０例肺动脉栓塞患者进行回顾性分析，年龄２８～７８岁。应用ＩｍａｔｒｏｎＣ１５０ＥＢＣＴ机，连续容积扫描（ＣＶＳ）或单层序列扫描（ＳＳＭ），层厚３ｍｍ或６ｍｍ（以３ｍｍ为主），扫描时间０．１秒，造影剂流速约２．８～３．３ｍｌ／ｓ，造影剂总量约４５～９０ｍｌ，扫描延迟时间１０～２０秒。结果对２０例４４２支血管进行分析，２５５支发生肺动脉栓塞（５７．７％）。４７．５％肺叶以上动脉（主肺动脉、左右肺动脉主干及双侧中间段动脉）、６３．３％肺叶动脉及５９．７％肺段动脉受累。肺动脉栓塞的ＣＴ形态：（１）直接征象：①腔内充盈缺损，包括部分充盈缺损（７６．９％）、附壁充盈缺损（９．２％）、完全堵塞（９．６％）及轨道征（４．３％）。其中前三者为慢性肺动脉栓塞的征象，而轨道征则提示急性肺动脉栓塞，对临床治疗有重要意义，动态显示还可见栓子在腔内活动。②肺动脉纤细，腔内灌注减低、不均匀（纵隔窗）。（２）间接征象：部分病例可见“马赛克”征（肺窗）及肺梗死灶。其他还包括肺纹理稀疏、右心室增大及右心功能下降等。结论ＥＢＣＴ是一种无?

bjective To evaluate the effectiveness of EBCT in diagnosis of pulmonary embolism(PE). Methods 20 patients aged from 28-78 years had PE demonstrated by EBCT. EBCT study was performed using Imatron C150 scanner. Continuous volume scan(CVS) or single slice mode(SSM) were used with slice thickness of 3 mm or 6 mm. Scan time was 0.1 s. Nonionic contrast medium was administered by automatic injector with flow rate of 2.8-3.3 ml/s and total dosage of 45-90 ml. Delay time was 10-20 s. Results Among 442 pulmonary arteries in 20 cases, 255 vessels were involved with PE (57.7%). 47.5% of pulmonary artery trunk, main pulmonary artery and interlobar artery, 63.3% of lobar artery and 59.7% of segmental artery had PE. EBCT features of PE: (1) Direct signs: Intraluminal filling defect: including partial filling defect (76.9%), mural filling defect (9.2%), total occlusion (9.6%) and railwaytrack sign (4.3%). The first three signs indicate chronic PE and the last one (railwaytrack sign) indicate acute PE. It's very important to distinguish chronic from acute PE from the stand point of clinical treatment. Smaller caliber of pulmonary artery , low and nonuniform density of contrast medium in arterial lumen (mediastinal window). (2) Secondary signs: include 'mosaic sign'(lung window), focus of pulmonary infarction, local oligemia, enlargement and failure of right ventricle. Conclusions EBCT is a noninvasive and effective method for examining PE .It can play a significant role in clinical diagnosis of PE.