肺动脉CT血管成像触发点位置及不同图像后处理技术的选择探讨

目的探讨肺动脉CT血管成像(CTPA)触发点位置及不同图像后处理技术的选择。方法选择2016年7月至2017年7月我院接诊的疑似肺栓塞患者50例为研究对象,均接受CTPA检测。将50例患者按随机数字表法分为两组,A组25例,触发点感兴趣区(ROI)位于肺动脉干,对比剂总量50 m L,阈值80HU; B组25例,ROI位于主动脉窗水平的上腔静脉内,对比剂总量30 m L,阈值90 HU。以上两组注药完毕均以相同流率追加生理盐水20mL。分析不同后处理重组方法对肺动脉栓子的检测情况,并比较两组右下肺静脉、肺动脉干CT值和肺动脉显示率。结果入组的50例患者中有28例确诊为肺栓塞,发现578个栓子。VRT对左右肺动脉检测率为100. 00%,其余各部位栓子检测率较低,MIP对左右肺动脉、亚段以下肺动脉检测率较高,而MPR除了对亚段以下肺动脉检测率较低外,对其他部位栓子检测率均为100. 00%; A组6级肺动脉显示率为88. 00%(22/25),B组6级肺动脉显示率为80. 00%(20/25),差异无统计学意义(P 0. 05); A组中右下肺静脉CT值高于B组,差异有统计学意义(P 0. 05); A组与B组肺动脉干CT值比较,差异无统计学意义(P 0. 05)。结论 CTPA检查时ROI位于上腔静脉内可提高图像质量,减少对比剂用量; MPR较MIP、VRT对肺动脉栓子的检测率较高,综合运用不同图像后处理技术,对于病变的显示效果更佳,利于提高诊断准确性。     

16排螺旋CT肺血管造影及重建技术在老年人肺动脉栓塞诊断中的应用

目的 研究16层螺旋CT肺血管造影及重建技术在老年人肺动脉栓塞(肺栓塞)诊断中的应用.方法 24例疑为肺栓塞的老年患者应用16层螺旋CT行肺动脉成像.CT后重建技术包括最大密度投影(MIP)、多平面重建(MPR)及容积再现(VR).结果 24例老年患者共发现肺动脉栓子161个,肺栓塞的直接CT征象:完全闭塞27支(占16.8%),不规则的充盈缺损109支(67.7%),中心性充盈缺损(轨道征)25支(15.5%).横断面图像共检出栓子161个,MPR像共检出153个(95.0%),MIP像检出113个(70.2%),VR像检出69个(42.9%).MIP和VR图像对栓子的显示效果相对较差,尤其是对肺叶及其以下肺动脉分支内栓子的显示效果明显低于横断面组(x2值分别为235.36和243.4l,均P＜0.05).结论 16层螺旋CT肺血管造影无创、快速、敏感性高,应当作为老年人肺栓塞的首选检查方法.

Abstract：

Objective To study the application of pulmonary angiography and reconstruction techniques with 16-detector row spiral CT in the diagnosis of pulmonary embolism (PE) in the elderly.Methods Twenty-four elderly patients with suspected pulmonary thromboembolism received detection of CT and pulmonary artery angiography ( CTPA ) on 16-detector MSCT.Post-reconstruction techniques included maximum intensity projection (MIP), volume rendering (VR)and multiple planar reformation (MPR). Results A total of 161 pulmonary artery thrombi were detected in 24 elderly patients. The direct signs of pulmonary embolism included total occlusion (16.8%, 27/161), partial filling defect (67.7%, 109/161) and central filling defect or track sign (15.5%, 25/161). A total of 161 pieces of pulmonary thrombi were detected in transect image, 153 (95.0%) in MPR, 113 (70.2%) in MIP and 69 (42.9%) in VR. The transect image excelled evidently MIP and VR image in displaying pulmonary thrombi, especially the thrombi in pulmonary lobe and pulmonary artery branch (χ2 =235.36 and 243.41, P＜0.05). Conclusions The 16-detector row spiral CT pulmonary angiography is non-invasive, fast and high sensitive, it should be the first choice for the diagnosis of PE in the elderly.     

多层螺旋CT肺血管造影技术在肺栓塞诊断中的应用

目的探讨多层螺旋CT肺血管造影在肺动脉栓塞诊断中的临床应用。方法使用16层螺旋CT对20位肺动脉栓塞患者进行血管成像检查。应用准直1.0 mm,螺距1.25进行扫描,将得到的原始数据行层厚1.25 mm、3.0 mm轴面重建,MIP 2 mm、5 mm多视角多平面重组及MPR重组。不同后处理技术的检出栓塞动脉支数进行比较。结果多层螺旋CT扫描肺动脉主干、左右肺动脉及叶、段、亚段动脉显示良好,共累及肺动脉血管232支,以上5种重建方法对肺动脉主干及叶动脉的栓塞,显示检出结果一致。对段及亚段动脉的栓塞MPR优于其它后处理方法(P0.05)。结论多层螺旋CT肺血管造影是肺栓塞安全、敏感性且特异性高的无创性诊断方法。     

16层螺旋CT对肺栓塞及下肢静脉血栓行联合成像的初步研究

目的 探讨16层螺旋CT同时扫描肺动脉、下肢深静脉的联合成像检查技术.方法 15例疑为肺动脉栓塞的病人在16层螺旋CT上行肺动脉和下肢静脉联合成像.CT后处理包括最大密度投影（MIP）,多平面重建（MPR）及容积再现（VR）.结果 肺栓塞、下肢静脉血栓同时存在者8例,单纯肺动脉栓塞者2例,单纯下肢动脉栓塞者1例,二者均正常者4例.不同重建层厚均可清晰显示肺动脉栓子.肺动脉、下肢静脉增强后的CT值显著高于栓子的CT值.结论 16层螺旋CT联合肺动脉、下肢静脉成像能为肺栓塞的诊断提供新的检查方法.     

320排CT肺减影技术对亚段肺栓塞的诊断价值

目的 探讨320排CT肺减影技术进行CTPA诊断肺栓塞同时，是否可以提供更多的诊断信息，提高亚段肺栓塞的阳性检出率。方法 98例PE患者行CT肺减影扫描获取常规CTPA图与肺减影图。两名医师独立完成常规CTPA图及肺减影图的诊断，并记录栓子的位置及类型。采用Kappa系数检验两位医师的诊断一致性，采用McNemar检验比较常规CTPA与减影CT在肺栓塞诊断中的差异。结果 两位医师在肺动脉干水平、叶肺动脉水平、段肺动脉水平和亚段肺动脉水平诊断一致性良好，Kappa值均>0.75。常规CTPA组与肺减影组在肺动脉干水平、叶肺动脉水平及段肺动脉水平栓子检出率差异不具有统计学意义，在亚段肺动脉水平差异具有统计学意义(P<0.01)。结论 320排CT肺减影技术可以为肺栓塞的诊断提供更多信息，提高亚段肺栓塞检出率及医师的诊断一致性水平。     

多层螺旋CT血管成像技术在肺动脉栓塞中的应用价值

目的探讨多层螺旋CT血管成像技术在肺动脉栓塞中的应用价值。方法回顾分析11例被证实的在肺动脉栓塞患者,行血管造影（CTA）检查,后处理采用多平面重建（MPR）、曲面重建（CPR）、最大密度投影（MIP）及容积重建（VR）等多种后处理技术。结果肺动脉增强后的CT值显著高于栓子的CT值,同时,CT横断面图像结合多平面重建、曲面重建、最大密度投影和容积重建等处理清晰地显示了肺动脉栓塞的部位和栓子形态。结论利用多层螺旋CT血管成像技术可以清晰显示肺动脉的栓塞部位和血栓栓子的形态,对肺栓塞的诊断具有明显的技术优势和较高的临床价值。     

虚拟支气管镜导航软件——DirectPath的初步应用

目的 探索虚拟支气管镜导航软件(DirectPath)使用不同重建层厚的CT图片数据重建出三维支气管树的效果,评估该软件引导常规/超细支气管镜进入肺外周目标支气管的能力.方法 入选行胸部CT扫描发现肺孤立性结节者60例,其中8排螺旋CT扫描组(8排组)30例,64排螺旋CT扫描组(64排组)30例.8排组获取的图片可以刻录成1.25 mm层厚的重建数据,64排CT组图片可分别刻录成1.25 mm和0.625 mm两组层厚的重建数据.将所有入选者的重建数据导入DirectPath导航软件中,软件自动重建出三维支气管树,并模拟出目标支气管的图像,记录所有入选者重建出的三维支气管树及右B1a、右B6a、右B10a 3支支气管最远端所在的支气管级别和最短直径.结果 所有入选者均重建出了三维支气管树.1.25 mm层厚时,64排组重建出的三维支气管树优于8排组(Z＝-2.849,P=0.004),且64排组重建出的右B1a、右B6a级别更远.64排组中,0.625 mm层厚较1.25 mm层厚能重建出级别更远、直径更小的支气管,但2种层厚重建出的三维支气管树差异无统计学意义(Z＝-1.732,P=0.083).60例入选者,1.25 mm层厚时,重建出右B1a、右B6a、右B10a 3支支气管的最远级别及最短直径差异无统计学意义(P值均＞0.05),3支支气管重建出级别大于6级(含6级)的比例分别为66.7％、60.0％、65.0％,而当64排组0.625 mm层厚时,上述比例分别为90.0％、90.0％、88.3％.结论 虚拟支气管镜导航软件(DirectPath)使用64排CT扫描0.625 mm层厚的数据可以重建出较好的支气管树,其具备引导常规/超细支气管镜进入肺外周目标支气管的能力.     

心电门控双源CTPA评价急性肺栓塞及其右心室功能

目的探讨心电门控双源CT肺动脉血管成像(CTPA)在评价急性肺栓塞(APE)及其右心室功能的临床价值。方法 54例患者行回顾性心电门控下CTPA检查后,经图像后处理并进行重建,观察肺动脉栓塞的分布、程度并计算肺栓塞指数,分析心功能。根据栓塞位置分为两组,中央型与周围型。比较有无肺栓塞患者右心功能参数组间差异;对比不同栓塞程度及栓塞部位组间心功能参数差异性。结果肺栓塞组右室舒张末期容积及收缩末期容积均较无栓塞组高,右室射血分数(RVEF)值较无栓塞组减低(P0.05),右室每搏量较无栓塞组减低,两组间差异无统计学意义(P0.05)。随着栓塞程度加重,RVEF逐渐减低,且三组间RVEF整体差异有统计学意义(P0.05)。中央型较周围型、无栓塞组RVEF明显减低,RVEF在三组间差异均有统计学意义(P0.05)。结论 CTPA可准确地评价肺栓塞分布、程度及栓塞指数,评价的心功能对临床也具有一定的价值。     

亚段及亚段以下肺动脉栓塞漏误诊原因分析

目的 分析亚段及亚段以下肺动脉栓塞漏误诊原因,以提高肺动脉远端分支栓塞诊断的准确性.方法 收集2009年1月-2010年10月临床怀疑肺动脉栓塞行64层螺旋CT肺动脉血管造影检查者624例,检查存在肺动脉检塞漏误诊者56例,以0.625 mm层厚显示的检子数为标准,计算亚段及亚段以下肺动脉栓子漏误诊数目并分析原因.结果 亚段肺动脉栓子漏诊137个,误诊22个,亚段以下肺动脉栓子漏诊42个,误诊7个.漏诊常见原因为用于诊断的图像质量欠佳、重组图像层厚过厚、未应用多种方法联合观察及肺部存在疾患,误诊常见原因为图像质量欠佳、肺部存在疾患及诊断经验不足.结论 良好的图像质量、适当的重组层厚、多种后处理技术的联合应用及丰富的诊断经验是提高肺动脉远端分支栓塞诊断准确性的关键.     

双源计算机断层摄影术双能量肺灌注成像与肺动脉造影诊断肺栓塞的对比研究

目的:与计算机断层摄影术肺动脉造影(CTPA)比较,探讨双源计算机断层摄影术(CT)双能量肺灌注成像(DEPI)对肺栓塞的诊断价值。方法:49例疑似肺栓塞患者进行DEPI扫描,最终19例CTPA确诊肺栓塞的患者纳入研究。以80 k V的数据得到CTPA图像,采用肺灌注成像软件(Lung PBV)后处理得到DEPI图像,以肺段为单位观察CTPA图像上肺栓塞的位置、类型,DEPI图像上肺灌注缺损的位置及形态,并对两者的类型进行相关性分析,计算CTPA与DEPI诊断肺栓塞的一致性,并对不一致的原因进行分析。结果:380个肺段,CTPA检出162个肺段有肺栓塞,DEPI检出155个肺段有灌注缺损或降低,部分型肺栓塞主要为斑点状、斑片状灌注缺损或无缺损,完全型肺栓塞则以段或亚段分布的灌注缺损为主,两者存在相关性(χ2=305.5,P=0.000)。CTPA与DEPI诊断肺栓塞的符合率为83.42%,KAPPA系数值为0.659。结论:DEPI的表现与CTPA上肺栓塞的程度及类型有关,两者联合有助于肺栓塞的诊断。     

Pleural effusion in patients with pulmonary embolism

Background and objective: It has been suggested that pulmonary embolism (PE) is an under‐recognized cause of pleural effusion. This study aimed to (i) establish the incidence and clinical relevance of pleural effusion in patients with pulmonary emboli; and (ii) determine if there is a relationship between development of pleural effusions and the location of emboli and number of pulmonary arteries involved. Methods: A retrospective analysis of all CT pulmonary angiograms (CTPA) performed over 12 months on adult patients with clinically suspected PE in a hospital which used CTPA as first‐line imaging investigation for PE. Results: Of 285 CTPA, 60 patients (21%) had evidence of pulmonary emboli (38 had both central and peripheral clots and 22 peripheral emboli only). Emboli were bilateral in 39 cases and unilateral in 21 cases. Pleural effusion was present in almost one half (n = 29, 48%) of the patients with pulmonary emboli. Patients with pulmonary emboli were more likely to have a pleural effusion (OR 2.2 (95% CI: 1.1–4.7), P < 0.05) than patients without PE; however, the effusions were generally very small. Most (86%) of the effusions were present on the same side as the emboli. The location of emboli and number of arteries involved did not predict the presence of pleural effusions. Conclusions: Pleural effusion is common in patients with pulmonary emboli demonstrated on CTPA. These effusions are small and seldom alter clinical management. Clinicians should therefore have a high threshold of suspicion in attributing large or contralateral pleural effusions to embolic diseases without excluding alternative diagnoses.     

Diagnostic accuracy of three-dimensional contrast-enhanced MR angiography at 3-T for acute pulmonary embolism detection: Comparison with multidetector CT angiography

Background

Three-dimensional contrast-enhanced MR pulmonary angiography (MRPA) is a suitable option for pulmonary embolism (PE) detection. However, there have been few reports on the diagnostic accuracy of MRPA for PE detection in a 3-T MR system. The purpose of this study was to evaluate the accuracy of MRPA in a 3-T MR system to detect acute PE with multidetector CT pulmonary angiography (CTPA) as reference standard.

Methods

Twenty-seven patients (18 males and 9 females, mean age 38.9 ± 14.4 years) underwent both MRPA and CTPA within 3 days (range, 0–3 days) for evaluating PE. Pulmonary emboli in MRPA were independently analyzed on a per-patient and per-lobe basis by two radiologists. CTPA was regarded as reference standard, which was evaluated by another two radiologists in consensus. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy for PE detection were calculated. Weighted κ values were calculated to evaluate agreement between readers.

Results

Twenty-four patients had PE in 55 lung lobes in CTPA, while 3 patients had no PE detected. Readers 1 and 2 correctly detected 47 and 46 lung lobes having clots in 24 and 23 patients, corresponding to sensitivities, specificities, PPV, NPV, and accuracies of 100%, 100%, 100%, 100%, 100%; 100%, 66.7%, 96.0%, 100%, 96.4% on a per-patient basis and 85.5%, 100%, 100%, 90.9%, 94.1%; 83.6%, 93.7%, 90.2%, 89.2%, 89.6% on a per-lobe basis; respectively. Excellent inter-reader agreement (κ values = 1.00 and 0.934; both P < 0.001) were found for detecting PE on a per-patient and per-lobe analysis.

Conclusion

Three-dimensional contrast-enhanced MRPA with a 3-T MR system is a suitable alternative modality to CTPA to detect PE on a per-patient basis based on this small cohort study.     

多层螺旋CT肺动脉造影在诊断周围型动脉栓塞中的应用

目的探讨多层螺旋CT肺动脉造影(MSCTPA)对周围型肺栓塞(PPE)的诊断价值。方法回顾性分析417例MSCTPA的患者资料,结合多层面曲面重组成像(CPR)、最大密度投影(MPR)、曲面重组(MIP)等图像后处理手段,分析PPE的MSCTPA的表现。结果检出的188例周围型动脉肺栓塞患者中,孤立性PPE 1例,PPE合并中心型肺动脉栓塞187例。188例患者共检出PPE 1583支,其中,累及亚段1012支,亚亚段PE 473支,亚亚段以远分支PE 98支。结论 MSCTPA能够准确显示PPE的范围及影像表现特征,对诊断PPE及病情评估具有重要的影像学参考价值,是诊断PPE的首选影像学检查手段。     

Spiral CT for pulmonary embolism: the paradigm has shifted

Computed tomography (CT) is rapidly becoming the first-line modality for imaging pulmonary embolism (PE). However, limitations for the accurate diagnosis of small peripheral emboli have prevented the unanimous embrace of CT as the new standard of reference for imaging PE, although the actual significance of isolated peripheral emboli is uncertain. At the same time, the high negative predictive value of CT pulmonary angiography for excluding clinically significant PE has been established. The introduction of multidetector-row spiral CT has greatly improved visualization of peripheral pulmonary arteries and detection of small emboli. Previous concerns regarding the use of spiral CT for the accurate diagnosis of peripheral pulmonary emboli should thus be overcome. Multidetector-row spiral CT has become a widely available and cost-effective technology and appears to have surpassed other imaging modalities for the accurate detection of central and peripheral PE. In this review, the authors assess the current role of spiral CT in the diagnostic algorithm of PE.     

CT肺动脉及支气管动脉联合造影对咯血患者的诊断价值

目的 探讨建立CT肺动脉(PA)及支气管动脉(BA)联合造影的方法及其对咯血患者的诊断价值.方法 连续纳入北京朝阳医院2007年6月至2009年7月36例中等量及以上咯血住院患者,其中男21例,女5例,年龄27 ～ 83岁,平均(56±14)岁.使用16排螺旋CT,静脉注射对比剂后,首先完成CT肺动脉造影(CTPA),延迟时间12～16 s,继之完成CT支气管动脉造影(CTBA),延迟时间26～28 s,经图像重建后对PA及BA进行评价.结果 36例患者CTPA检查发现7例PA异常(肺栓塞3例,PA畸形、原发性PA平滑肌肉瘤、PA边缘模糊及右下PA闭塞各1例).36例患者CTBA检查共显示37支右侧BA,其中11支迂曲增粗、40支左侧BA及3支非支气管体循环动脉,其中来源于腹主动脉的1支迂曲增粗.异常血管与肺部疾病关系密切.结论 利用16排螺旋CT技术,可进一步完成CTPA及CTBA检查,清楚显示异常的PA及BA,对咯血的诊断及治疗具有重要价值.     

Spiral computed tomography for acute pulmonary embolism

There is still considerable debate about the optimal diagnostic imaging modality for acute pulmonary embolism. If imaging is deemed necessary from an initial clinical evaluation such as d-dimer testing, options include nuclear medicine scanning, catheter pulmonary angiography, and spiral CT. In many institutions, spiral CT is becoming established as the first-line imaging test in daily clinical practice. With spiral CT, thrombus is directly visualized, and both mediastinal and parenchymal structures are evaluated, which may provide important alternative or additional diagnoses. However, limitations for the accurate diagnosis of small peripheral emboli, with a reported miss rate of up to 30% with single-slice spiral CT so far, have prevented the unanimous embrace of spiral CT as the new standard of reference for imaging pulmonary embolism. The clinical significance of the detection and treatment of isolated peripheral pulmonary emboli is uncertain. Evidence is accumulating that it is safe practice to withhold anticoagulation in patients with suspected pulmonary embolism on the basis of a negative spiral CT study. Remaining concerns about the accuracy of spiral CT for pulmonary embolism detection may be overcome by the introduction of multidetector-row spiral CT. This widely available technology has improved visualization of peripheral pulmonary arteries and detection of small emboli. The most recent generation of multidetector-row spiral CT scanners appears to outperform competing imaging modalities for the accurate detection of central and peripheral pulmonary embolism. In this review, we assess the current role and future potential of CT in the diagnostic algorithm of acute pulmonary embolism.     

Pulmonary embolism: computer-aided detection at multidetector row spiral computed tomography

BACKGROUND: We aimed to evaluate the feasibility and performance of a computer-aided detection (CAD) tool for automated detection of segmental and subsegmental pulmonary emboli. METHODS: A CAD tool (ImageChecker CT, R2 Technology, Inc) for automated detection of pulmonary emboli was evaluated on multidetector-row CT studies of varying diagnostic quality in 23 patients (13 female, mean age 52 y) with pulmonary embolism (PE) and of 13 patients (all female, mean age 49 y) without PE. A collimation of 16 x 1 mm and a reconstructed section width of 1.25 mm had been used in each patient. The performance of the CAD tool for the detection of emboli in the segmental and subsegmental pulmonary arterial tree was assessed. Consensus reading of the same studies by 2 radiologists, with a third for adjudication, for the identification of segmental and subsegmental pulmonary emboli was used as the standard of reference. RESULTS: Consensus reading revealed 130 segmental pulmonary emboli and 107 subsegmental pulmonary emboli in the 23 patients with PE. All 23 patients with PE were correctly identified as having PE by the CAD system. In a vessel-by-vessel analysis, the sensitivity of the CAD algorithm was 92% (119/130) for the detection of segmental pulmonary emboli and 90% (92/107) for subsegmental pulmonary emboli. The overall specificity, positive predictive value (95% confidence interval) and negative predictive value (95% confidence interval) of the algorithm were 89.9%, 63.2% (57.9%-68.2%) and 97.7% (96.7%-98.4%), respectively. The average false positive rate of the CAD algorithm was 4.8 (range 1 to 9) false positive detection marks per case. CONCLUSION: CAD of segmental and subsegmental pulmonary emboli based on 1-mm multidetector-row CT studies is feasible. Application of CAD tools may improve the diagnostic accuracy and decrease the interpretation time of computed tomographic angiography for the detection of pulmonary emboli in the peripheral arterial tree and further enhance the acceptance of this test as the first line diagnostic modality for suspected PE.     

Multislice CT angiography in the follow-up of fenestrated endovascular grafts: effect of slice thickness on 2D and 3D visualization of the fenestration stents

PURPOSE: To investigate the effect of multislice computed tomography (CT) protocols on the visualization of target vessel stents in patients with abdominal aortic aneurysm (AAA) treated with fenestrated endovascular grafts. METHODS: Twenty-one patients (19 men; mean age 75 years, range 63-86) undergoing fenestrated endovascular repair of AAA were retrospectively studied. Multislice CT angiography was performed with several protocols, and the section thicknesses used in each were compared to identify any relationship between slice thickness and target vessel stents visualized on 2-dimensional (2D) axial, multiplanar reformatted (MPR), and 3-dimensional (3D) virtual intravascular endoscopy (VIE) images. Image quality was assessed based on the degree of artifacts and their effect on the ability to visualize the configuration, intra-aortic location, and intraluminal appearance of the target vessel stents and measure their protrusion into the aortic lumen. RESULTS: There were 7 different multislice CT scanning protocols employed in the 21 patients (25 datasets, with 2 sets of follow-up images in 4 patients). The slice thicknesses and numbers (n) of studies included were 0.5 (n=3), 0.625 (n=6), 1.0 (n=1), 1.25 (n=9), 2.5 (n=3), 3.0 (n=1), and 5.0 mm (n=2). Of these CT protocols, images (especially 2D/3D reconstructions) acquired at 2.5, 3.0, and 5.0 mm were significantly compromised by interference from artifacts. Images acquired with a slice thickness of 1.0 or 1.25 mm were scored equal to or lower than those acquired with a submillimeter section thickness (0.5 or 0.625 mm), with minor degrees of artifacts resulting in acceptable image quality. CONCLUSION: Visualization of the target vessel stents depends on the appropriate selection of multislice CT scanning protocols. Our results showed that studies performed with a slice thickness of 1.0 or 1.25 mm produced similar image quality to those with a thickness of 0.5 or 0.625 mm. Submillimeter slices are not recommended in imaging patients treated with fenestrated stent-grafts, as they did not add additional information to the visualization.     

肺动脉栓塞的多层螺旋CT诊断与鉴别

目的研究肺动脉栓塞多层螺旋CT肺血管成像的影像表现,探讨与肺动脉栓塞表现相似疾病的鉴别,提高肺动脉栓塞诊断与鉴别诊断的水平。方法对21例肺动脉栓塞（1例为瘤栓）患者行多层螺旋CT肺动脉成像检查,图像采用10mm层厚,10mm层间距,和1．25层厚,0．625mm层间距进行重建,所获的数据传送至工作站运用MPR、MIP、VR技术后处理。结果20例中（不包括1例肺动脉肿瘤）,双侧肺动脉受累18例,单侧2例,病变累及131支肺动脉及分支。其中发生于左及右肺动脉远端18支,肺叶动脉38支、肺段动脉50支、肺段以下25支,CT显示的直接征象为肺动脉及分支血管内不同程度的充盈缺损,增强扫描不强化。充盈缺损依形态可分为4种：中心型（25支）、偏心型（61支）、附壁型（25支）、完全闭塞型（20支）。并存间接征象为主肺动脉及左右肺动脉增宽,局限性肺内灌注不均匀,肺梗死,胸腔积液及右房、右室增大。结论肺动脉栓塞在CT图像上形态多样,病变范围广泛,双侧发病多于单侧,主肺动脉受累少见。多层螺旋CT肺血管成像对本病的诊断有独特的优势,该方法能清晰显示肺动脉栓塞的直接征象和间接征象。为诊断及鉴别诊断提供可靠的影像学资料。