肺栓塞的影像学诊断

探讨肺栓塞与肺梗死的影像学的诊断价值。方法对２０例临床疑诊为肺动脉栓塞的病人进行了胸部Ｘ线平片,核素肺灌注扫描和数字减影肺动脉造影诊断对比。结果数字减影肺动脉造影阳性发现１０例,以此为金标准,胸部Ｘ线平片检查,敏感性４２．９％特异性３３．３％;核素肺灌注扫描检查,敏感性７２．７％特异性７７．８％。     

Comparison of conventional pulmonary angiography with intravenous digital subtraction angiography for pulmonary embolic disease

Intravenous digital subtraction pulmonary angiography was performed in 33 patients with suspected pulmonary embolism. It was performed as the initial examination, followed immediately by conventional film-screen pulmonary angiography performed with selective right or left main pulmonary injections. Intravenous studies of diagnostic quality were obtained in 31 of 33 patients (93.9%). Of the satisfactory intravenous studies, pulmonary embolism was correctly diagnosed in 12 cases and excluded in 18 cases. Emboli were detected in major and second-order branches, and occasionally in third-order branches as well. There was one false-positive intravenous pulmonary study, but the overall accuracy was 90.9% considering all studies and 96.8% excluding the two inadequate intravenous examinations. It is concluded that intravenous pulmonary angiography is an acceptable substitute for routine pulmonary angiography in most patients with suspected major pulmonary embolism. The technique is less expensive, and is safer, faster, and easier to perform than conventional pulmonary angiography.     

Digital angiography in pulmonary embolism

Pulmonary digital subtraction angiography was diagnostic in 98.3 per cent of patients with possible acute pulmonary embolism. The procedure was well tolerated even in severely ill patients. A large image intensifier made simultaneous imaging of both lungs possible, reducing the number of contrast injections necessary. Small volumes of low iso-osmolar concentration of modern contrast media were used. There was no need for catheterization of the pulmonary artery. Theoretical considerations and our limited experience indicate that this will reduce the number of complications compared with conventional pulmonary angiography. The procedure is rapidly performed and the diagnostic accuracy high. This makes digital subtraction angiography cost effective. Digital pulmonary angiography can be recommended as the primary diagnostic method in most patients with possible pulmonary embolism.     

实验性急性肺栓塞的比较影像学研究

目的　探讨核素肺灌注显像、增强螺旋CT及数字减影肺动脉造影对猪急性肺栓塞实验模型 (相当于人类亚肺段水平肺栓塞 )的影像学特点。方法　 13头中国实验用小型猪 ,经颈静脉注射明胶海绵栓子 (直径 3 8～ 4 2mm) ,制作肺栓塞模型后进行核素肺灌注显像、增强螺旋CT和数字减影肺动脉造影 ,以病理检查为标准 ,比较 3种检查方法的灵敏度和特异性。结果　对 195个肺段(动脉段 )进行分析 ,病理诊断阳性肺段 4 6个 ,阴性肺段 14 9个。核素肺灌注显像阳性肺段 5 1个 (包括假阳性肺段 11个 ) ,灵敏度为 87% ,特异性为 93% ;增强螺旋CT阳性肺段 4 4个 (包括假阳性肺段15个 ) ,灵敏度为 6 3% ,特异性为 90 % ;数字减影肺动脉造影阳性肺段 4 7个 (包括假阳性肺段 2个 ) ,灵敏度为 98% ,特异性为 99%。核素肺灌注显像病变检出率比增强螺旋CT高 (P <0 0 5 ) ,但与数字减影肺动脉造影相比差异无显著性 (P >0 0 5 )。增强螺旋CT可对栓子进行准确定位。结论　核素肺灌注显像对猪肺段 (相当于人类亚肺段 )肺栓塞的探测优于增强螺旋CT ,而后者对栓子定位优于前者 ;数字减影肺动脉造影对猪肺段肺栓塞诊断能力最强 ,但有创 ,应用受限。     

螺旋CT肺动脉造影对肺栓塞的诊断

目的：评价螺旋CT及其肺动脉造影诊断肺动脉栓塞（PE）的价值。方法：回顾性分析12例PE患,均行螺旋CT容积扫描,并在工作站进行图像后处理,获得肺动脉多平面重建图像及三维立体图像。结果：对12例196支肺动脉分支进行分析,受累率为46.4%;栓子发生在主肺动脉、左右肺动脉干及叶段肺动脉。多平面重建图像上表现为充盈对比剂血管内有充盈缺损区,或其远侧方无对比剂充填区。肺动脉成像示,主干血管内可见充盈缺损影,或呈截断状影;叶栓塞或段栓塞亦呈突然“截断状”,其远侧方肺动脉分支不显影或呈纤维状。结论：螺旋CT肺动脉造影不仅可以获得轴位图像,而且可以获得立体图像,可多轴向旋转观察PE部位,是诊断叶或段以上PE可靠而直观的检查方法。     

64层螺旋CT肺血管造影在肺栓塞诊疗中的应用价值

目的 探讨64层螺旋CT在肺栓塞诊断及治疗中的指导作用。方法 63例患者均行64层螺旋CT肺血管造影(CTPA),并进行多种形式的图像重建结合轴位图像分析。结果 64层螺旋CTPA对63例患者肺动脉各级管腔内的栓子均明确显示,共累及肺动脉303支;图像分析结果伞部显示肺栓塞的直接征象为:主肺动脉和(或)左右肺叶、段、亚段血管腔内充盈缺损和血管阻塞;部分显示肺栓塞的间接征象为:马赛克征、右心房及右心室肥厚及扩张、肺动脉扩张、胸腔积液、肺不张及实变(肺梗死)等。62例患者经溶栓治疗后复查CTPA,其中,栓子完全消失者47例,栓子明显缩小者11例,溶栓治疗效果差者3例,考虑为慢性肺栓塞。结论 64层螺旋CTPA是临床最有效的诊断肺栓塞及溶栓后疗效评价的无创性方法之一。     

Risk of pulmonary embolism after negative MDCT pulmonary angiography findings

OBJECTIVE: The purpose of our study was to determine the risk of pulmonary embolism in patients who have negative MDCT pulmonary angiography findings. SUBJECTS AND METHODS: In this prospective study, one hundred two consecutive patients with suspected pulmonary embolism underwent MDCT pulmonary angiography. Scans were reviewed jointly by two observers and findings recorded by consensus. Observers noted whether pulmonary embolism or other disease was present. No pulmonary embolism was seen in 85 patients (52 men and 33 women; age range, 20-94 years; mean age, 60 years) who were followed up for a mean of 9 months (range, 4-13 months) for evidence of subsequent pulmonary embolism. RESULTS: One patient had a diagnosis of pulmonary embolism made within 3 weeks of undergoing CT pulmonary angiography. MDCT pulmonary angiography showed additional potentially significant findings in 76% of patients; 47% of these findings were not suspected on chest radiography. CONCLUSION: The risk of pulmonary embolism at a mean of 9 months after negative MDCT pulmonary angiography findings is 1%. In our study of patients without pulmonary embolism, MDCT pulmonary angiography revealed other causes for individual patients' signs or symptoms in most cases.     

64层螺旋CT肺血管造影在肺栓塞诊疗中的应用价值

目的 探讨64层螺旋CT在肺栓塞诊断及治疗中的指导作用.方法 63例患者均行64层螺旋CT肺血管造影(CTPA),并进行多种形式的图像重建结合轴位图像分析.结果 64层螺旋CTPA对63例患者肺动脉各级管腔内的栓子均明确显示,共累及肺动脉303支;图像分析结果伞部显示肺栓塞的直接征象为:主肺动脉和(或)左右肺叶、段、亚段血管腔内充盈缺损和血管阻塞;部分显示肺栓塞的间接征象为:马赛克征、右心房及右心室肥厚及扩张、肺动脉扩张、胸腔积液、肺不张及实变(肺梗死)等.62例患者经溶栓治疗后复查CTPA,其中,栓子完全消失者47例,栓子明显缩小者11例,溶栓治疗效果差者3例,考虑为慢性肺栓塞.结论 64层螺旋CTPA是临床最有效的诊断肺栓塞及溶栓后疗效评价的无创性方法之一.     

Scintigraphic probability and angiographic diagnostic certainty in acute pulmonary embolism

The objectives of this study were to determine if diagnostic certainty on angiography correlates with scintigraphic probability for the diagnosis of pulmonary embolism. From a total of 160 consecutive patients who underwent both nuclear imaging and invasive selective pulmonary angiography, we reviewed the xenon-133 ventilation images in 2 posterior oblique views and the Tc-99m macroaggregated serum albumin perfusion scans and angiograms of 40 patients (15 men, 25 women; average age 57 years) who were discharged from the hospital on anticoagulants with a diagnosis of pulmonary embolism. The angiograms were reviewed and the diagnosis of embolism was considered certain in the presence of an intraluminal filling defect, a trailing embolus, or a branch occlusion equal to or larger than a segmental branch (n=29; 73%), and uncertain when the studies were reinterpreted as either equivocal or negative or in the presence of a single, small subsegmental filling defect of questionable clinical significance. The ventilation-perfusion scans were read as high (n=18; 45%), intermediate (n=10; 25%), or low (n=12; 30%) probability. The proportion of patients with diagnostic certainty on angiography in the high-, intermediate-, and low-probability scintigraphic subgroups was, respectively, 100% (18 of 18), 70% (7 of 10), and 33% (4 of 12) (P=0.004). In patients diagnosed with pulmonary embolism based on selective angiography, a lower probability of pulmonary embolism on ventilation-perfusion scintigraphy correlates with a lesser degree of diagnostic certainty on angiography and a higher incidence of single subsegmental emboli.     

Role of a quantitative D-dimer assay in determining the need for CT angiography of acute pulmonary embolism

OBJECTIVE: Our goal was to use the results of a quantitative D-dimer assay to determine the need for pulmonary CT angiography in patients suspected of having acute pulmonary embolism. MATERIALS AND METHODS: From July 2001 to December 2002, 755 patients underwent pulmonary CT angiography for the evaluation of acute pulmonary embolism. A rapid, fully automated quantitative D-dimer assay was obtained in more than half the patients. The electronic medical records of the patients were subsequently reviewed to analyze the negative predictive value of the D-dimer assay in the diagnostic workup of acute pulmonary embolism and to determine the outcome of the patients who had negative findings on both D-dimer assay and pulmonary CT angiography at 3-month follow-up. RESULTS: Of the 755 patients who underwent pulmonary CT angiography, 666 (88.2%) had negative findings, 73 (9.7%) had positive findings, and 16 (2.1%) were indeterminate. A total of 426 patients underwent both pulmonary CT angiography and D-dimer level evaluation, and 84 of these had negative findings (< 0.4 microg/mL) on D-dimer assay. Eighty-two of the 84 patients with negative findings on D-dimer assay had negative findings on pulmonary CT angiography; two were indeterminate and both subsequently had low-probability ventilation-perfusion studies. Among patients with positive D-dimer assays, no one with a level between 0.4 and 1.0 microg/mL had pulmonary CT angiography with findings positive for pulmonary embolism. CONCLUSION: A quantitative D-dimer assay was effective in excluding the need for pulmonary CT angiography and had high negative predictive value when the D-dimer level was less than 1.0 microg/mL.     

Wedge and subselective pulmonary angiography in pulmonary hypertension secondary to venous obstruction

Pulmonary wedge or subselective angiography provided key diagnostic information in two cases of pulmonary hypertension secondary to pulmonary venous obstruction. Whereas conventional pulmonary angiograms and ventilation-perfusion lung scans were interpreted as showing embolism, plain radiographs demonstrated Kerley B lines, suggesting venous obstruction. Subselective or wedge angiography of nonopacified arteries verified their anatomical patency and also revealed venous stenoses, collaterals, and atrophy indicative of obstruction.     

Panvenography and pulmonary angiography in the diagnosis of deep venous thrombosis and pulmonary thromboembolism

In summary, high-quality pulmonary angiography remains the most accurate and reliable means of diagnosing pulmonary embolism. It can be performed with relative safety, and the inherent mortality risks with pulmonary angiography (in the range of 0.2 to 0.5 per cent in active angiography laboratories) must be weighed against the significant risks incurred with inaccurate diagnosis obtained without pulmonary arteriography. Pulmonary arteriography and transvenous catheter embolectomy can be of great benefit in sudden cardiovascular collapse due to massive pulmonary embolism. Transvenous catheter embolectomy has survival rates at least as good as those of open embolectomy, and it has the advantage that it can be performed in any hospital with angiographic facilities and trained personnel, thus allowing more expeditious management of massive pulmonary embolism in hospitals that do not have cardiopulmonary bypass capabilities.     

The value of pulmonary angiography for the differential diagnosis of pulmonary embolism

The aim this study was to evaluate potential additional information of pulmonary angiography in patients with suspected pulmonary embolism and non-diagnostic lung scan findings. In a series of 150 patients who underwent pulmonary angiography for suspected venous thromboembolism, the images for potential alternative diagnoses other than pulmonary embolism were evaluated. All patients had non-diagnostic lung scan findings. Angiography was performed both by conventional and by digital subtraction angiography techniques. Images were evaluated by at least two experienced readers. Angiograms were scored for both presence or absence of pulmonary embolism, as well as other diagnoses. Pulmonary embolism was proven in 40 patients (27 %) and excluded in 105 patients (70 %), whereas non-interpretable images were obtained in 5 patients (3 %). A range of alternative diagnoses were detected by angiography: atelectasis (n = 24), pleural effusion (n = 15), pneumonia (n = 11), emphysematous bullae (n = 8), neoplasm (n = 3), atrial septum defect (n = 2), chronic thromboembolism (n = 1), and other diagnoses (n = 3). Overall, only 54 patients (36 %) had completely normal angiograms. Although pulmonary angiography remains the reference method for the diagnosis of pulmonary embolism, one has to be aware of other, often unexpected, but equally important findings which could influence the management of the patient. This aspect of pulmonary angiography has been insufficiently emphasized in the literature. Received: 2 April 1998; Revision received: 22 July 1998; Accepted: 4 November 1998     

双源CT肺动脉成像在肺动脉栓塞诊断中的应用价值

目的:探讨双源CT肺动脉成像对肺动脉栓塞(PE)的诊断价值.方法:对58例临床拟诊为PE的患者行双源CT肺动脉成像,总结PE的直接、间接征象及分型,并比较MPR、MIP、VR和CTVE对肺动脉栓子的显示效果.结果:直接征象:58例中45例诊断为PE,共发现栓子 658支(中心型170支,偏心型208支,附壁型74支,完...     

Acute pulmonary embolism: diagnosis with MR angiography

PURPOSE: To prospectively evaluate pulmonary magnetic (MR) angiography as a diagnostic examination for acute pulmonary embolism (PE). MATERIALS AND METHODS: Thirty-six consecutive patients (19 women, 17 men; age range, 28-84 years) underwent pulmonary digital subtraction angiography (DSA) and pulmonary MR angiography. MR angiograms were obtained during suspended respiration and the pulmonary arterial phase of gadolinium-based contrast medium injection. A steady-state gradient-recalled-echo sequence with free induction decay sampling was used. DSA studies were interpreted for the presence of acute PE by two independent radiologists; an adjudicator made the final decision on discordant interpretations. RESULTS: By using DSA, a total of 19 acute pulmonary emboli were depicted in 13 patients. Prospectively, 13 of these emboli were depicted by using MR angiography. MR angiography missed six emboli: Four required the DSA adjudicator to make the decision, and one was in a patient whose MR angiogram was acquired during breathing. Four of these six emboli were small subsegmental emboli, and two were segmental. CONCLUSION: Performed without pulmonary arterial catheterization, iodinated contrast media, or ionizing radiation, pulmonary MR angiography had a high accuracy for depicting lobar and segmental emboli, but was unable to depict four of five subsegmental emboli.     

16层螺旋CT肺动脉造影对肺栓塞诊断的临床价值

目的:探讨16层螺旋CT肺血管造影术(MSCTPA)诊断肺动脉栓塞的临床价值。方法:对临床拟诊肺栓塞的46例患者行MSCTPA检查及后重建技术,后重建方法包括容积再现(VR)、多平面重建(MPR)、最大密度投影(MIP)。结果:46例共发现栓子698个,其中肺动脉主干4个,左右肺动脉41个,叶动脉114个,段及亚段动脉539个。直接征象:①)血管截断征,表现为肺动脉管腔完全闭塞;②轨道征,表现为腔内充盈缺损位于血管中央,周围有对比剂环绕;③偏心性充盈缺损,表现为管腔内不规则充盈缺损偏向管壁一侧,边缘欠光整;④附壁性充盈缺损。间接征象:①肺窗观察见局限性的血管纹理稀疏,呈"马赛克征";②肺梗死,表现为肺外围以胸膜为基底的楔形或条状实变影;③胸腔积液、肺动脉高压、右心室肥大以及心包积液等。结论:MSCTPA能对肺动脉栓塞作出准确诊断,是无创、快速、安全、敏感的检查方法,并可追踪复查,评估治疗效果。     

Radiographic techniques for balloon-occlusion pulmonary angiography.

Pulmonary angiography was performed in 125 patients with suspected pulmonary embolism. Standard angiographic techniques were combined with balloon occlusion of pulmonary arterial branches using a double lumen catheter and contrast material injection distal to the occlusion. Vessel opacification was fluoroscopically monitored and images obtained with either a conventional cut-film camera, a spot-film camera, or cineangiography. Balloon-occlusion angiography improved image quality and contributed substantially to the radiographic diagnosis of pulmonary embolism in most patients. The technique is useful in patients too ill to undergo conventional angiography and may be performed at the bedside.     

Non-traumatic thoracic emergencies: CT diagnosis of acute pulmonary embolism: the first 10 years

Over the past 10 years, spiral CT angiography of the pulmonary arteries has reached a high accuracy in the evaluation of pulmonary embolism. Major advantages of CT compared with ventilation/perfusion lung scintigraphy and pulmonary angiography is direct visualization of clots in the pulmonary arteries, and to provide alternative findings or diagnosis. The recent introduction of multislice CT has improved the evaluation of peripheral pulmonary arteries, enabling high-resolution CT examinations over the entire thorax in a short breathhold. The examination techniques, imaging findings, pitfalls, and results of CT in the diagnosis of pulmonary embolism are reviewed in comparison with other diagnostic tests.     

Update on diagnostic strategies of pulmonary embolism

Acute pulmonary embolism is a frequent disease with non-specific findings, high mortality, and multiple therapeutic options. A definitive diagnosis must be established by accurate, non-invasive, easily performed, cost-effective, and widely available imaging modalities. Conventional diagnostic strategies have relied on ventilation-perfusion scintigraphy complemented by venous imaging. If the results are inconclusive, pulmonary angiography, which is regarded as the gold standard, is to be performed. Recently, marked improvements in CT and MRI and shortcomings of scintigraphy led to an update of the diagnostic strategy. Spiral CT is successfully employed as a second-line procedure to clarify indeterminate scintigraphic results avoiding pulmonary angiography. It can also be used as a first-line screening tool if service and expertise is provided. Venous imaging is indicated if CT is inconclusive. The MRI technique can be applied as an alternative second-line test if spiral CT is not available or is contraindicated. It has the greatest potential for further developments and refinements. Echocardiography should be used as a first-line bedside examination in critical patients. If inconclusive stabilized patients undergo spiral CT, unstable patients should be referred for pulmonary angiography. Chronic thromboembolic pulmonary hypertension is a rare sequela of acute pulmonary embolism which can be cured surgically. Morphology, complications, and differential diagnoses are better illustrated by spiral CT and MRA, whereas invasive acquisition of hemodynamic data is the sole advantage of angiography. Received: 25 February 1998; Revision received: 8 June 1998; Accepted: 10 June 1998     

Detection of central pulmonary embolism on computed tomography densitometry images before computed tomography pulmonary angiography

OBJECTIVE: The purpose of this article is to describe the imaging findings of acute central pulmonary embolism on computed tomography (CT) densitometry images performed before contrast-enhanced CT pulmonary angiography. METHODS: A retrospective review was conducted of reports from all CT pulmonary angiograms performed at our institution, and cases of acute central pulmonary embolism, defined as those with clot in the main, left, or right pulmonary arteries, were identified. Images of positive studies were reviewed on a picture archiving and communications system (PACS) workstation. RESULTS: A total of 1282 CT pulmonary angiograms were obtained for evaluation of possible acute pulmonary embolism, and 1 combined CT aortogram and pulmonary angiogram was performed for aortic dissection and acute pulmonary embolism. Two hundred fourteen (16.7%) examinations positive for acute pulmonary embolism were identified, 26 (12.1%, 2.0% of total examinations) of which had central clots. Of the 26 patients with central acute pulmonary embolism, 12 (46.1%, 5.6% of all positive studies and 0.9% of all CT pulmonary angiograms) had clots that were visible on the densitometry images. CONCLUSION: Although an uncommon finding, acute central pulmonary embolism can be detected on CT densitometry performed to optimize opacification of the pulmonary arteries for CT pulmonary angiography and may prove useful in selected clinical situations.