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.     

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     

CT angiography for diagnosis of pulmonary embolism: state of the art

In daily clinical routine, computed tomography (CT) has practically become the first-line modality for imaging of pulmonary circulation in patients suspected of having pulmonary embolism (PE). However, limitations regarding accurate diagnosis of small peripheral emboli have so far prevented unanimous acceptance of CT as the reference standard for imaging of PE. The development of multi-detector row CT has led to improved visualization of peripheral pulmonary arteries and detection of small emboli. The finding of a small isolated clot at pulmonary CT angiography, however, may be increasingly difficult to correlate with results of other imaging modalities, and the clinical importance of such findings is uncertain. Therefore, the most realistic scenario to measure efficacy of pulmonary CT angiography when PE is suspected may be assessment of patient outcome. Meanwhile, the high negative predictive value of a normal pulmonary CT angiographic study and its association with beneficial patient outcome has been demonstrated. While the introduction of multi-detector row technology has improved CT diagnosis of PE, it has also challenged its users to develop strategies for optimized contrast material delivery, reduction of radiation dose, and management of large-volume data sets created at those examinations.     

Digital subtraction angiography of the pulmonary arteries for the diagnosis of pulmonary embolism

A comparative study of radionuclide scanning (perfusion studies in all 18 patients and ventilation studies in 9) and digital subtraction angiography (DSA) was performed in 18 patients with suspected pulmonary thromboembolism. In 17 patients good visualization of the arteries was obtained with DSA; 10 of these patients had no pre-existing lung disease, and 7 had chronic obstructive pulmonary disease (COPD). The information provided by DSA in this small group was equal to or better than that of scintigraphy, especially in patients with COPD, and the reliability of DSA was superior to that of radionuclide scintigraphy. Methods for preventing motion artifacts with DSA are also described.     

CT pulmonary angiography for the detection of pulmonary embolism: interobserver agreement between on-call radiology residents and specialists (CTPA interobserver agreement)

PURPOSE: The aim of this study was to prospectively determine interobserver agreement between on-call radiology residents and specialists in the interpretation of computed tomographic pulmonary angiography (CTPA). METHODS: CTPA examinations obtained between January 2002 and March 2003 were interpreted by a radiology resident on call and by two radiology specialists. Agreement was assessed using percentage of agreement between interpreters and by the kappa coefficient. Sensitivity of residents' interpretations was calculated by relating them to the interpretation of Specialist 1, which served as the gold standard. RESULTS: Of the 81 CTPA examinations evaluated, there was agreement of 93% and 91% for the diagnosis of pulmonary embolism (PE) and of 97% and 85% for the exclusion of PE with Specialist 1 and 2, respectively. The concordance between residents' interpretations and those of Specialist 1 was very high (kappa=.8), and with those of Specialist 2 was high (kappa=.7). In all cases of agreement between the two specialists, there was complete agreement between the specialists' and the residents' intepretations. CONCLUSIONS: Our study showed good to very good agreement of residents' interpretations with each of the radiology specialists. Therefore, relying on the residents' preliminary interpretations during after-hour calls is reasonable.     

Interobserver agreement in the diagnosis of pulmonary embolism with helical CT

PURPOSE: Our objective was to asses the interobserver agreement in the detection of pulmonary embolism (PE) with contrast-enhanced helical CT at the main pulmonary, lobar and segmental arteries. A prospective study was carried out in 51 patients with suspected PE. Finally, 29 patients were diagnosed of PE. SUBJECTS AND METHODS: All patients were studied with helical CT. Images (5 mm collimation, 1.5 pitch factor, 3 mm reconstruction interval) were obtained after bolus contrast injection (120 ml, 4 ml/s, 15 s delay time). All cases were blinded and independently interpreted in three ways: two radiologists with different level of expertise and two expert radiologists reading by consensus. Agreement was evaluated by means of the kappa test. RESULTS: Kappa values for thrombi detection expressed an excellent agreement at the main (between 0.802 and 0. 946), lobar (between 0.915 and 0.958) and segmental (between 0.879 and 0.718) levels. For all vessels, mean kappa values were similar and excellent for all three combinations of readers. Arteries with more discrepancies were located mainly at the anterior and posterior areas of the upper lobes. CONCLUSIONS: The high degree of agreement shown in this study indicates that helical CT is a reproducible test in the diagnosis of PE to the segmental level. Isolated readings and levels of expertise do not influence agreement.     

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...     

MSCT肺血管成像对肺动脉栓塞的诊断价值

目的:探讨多层螺旋CT肺血管成像对肺动脉栓塞的诊断价值.方法:对24例肺动脉栓塞病例行多层螺旋CT肺动脉成像检查,图像采用1.0mm层厚、0.7mm层间距和0.75mm层厚、0.5mm层间距进行重建,CTPA后处理采用容积再现(VRT)、最大密度投影(MIP)和多平面重建(MPR),对重建的图像进行对照分析、比较优缺点.结果:24例病例中,病变共累及76支肺动脉,其中,主肺动脉6支、肺叶动脉36支、肺段动脉27支、亚段动脉7支.肺动脉栓塞病变显示,1.0mm及0.75mm层厚重建无显著性差异意义.结论:多层螺旋CT肺动脉成像具有安全、快速、无创优点,对肺动脉栓塞诊断特异性强、敏感性高,可作为肺动脉栓塞的首选检查方法.     

64-detector volume CT angiography in diagnosis of pulmonary embolism

目的:探讨64排容积CT(VCT)增强扫描在肺动脉栓塞诊断中的价值.方法:搜集17例经64排VCT增强扫描确诊的肺动脉栓塞患者的影像资料,所有病例均行多平面重组(MPR)、曲面重组(CPR)、三维容积成像(VRT)及最大密度投影(MIP)等后处理,对血栓的形态、部位、表现形式以及其它相关改变进行归类分析.结果:17例共累及肺动脉及其分支87处,其CT表现直接征象:中心性充盈缺损(轨道征)9处、偏心性或附壁性充盈缺损26处、完全阻塞性充盈缺损(血管截断征)13处;间接征象:肺动脉增宽7例、局限性肺纹理稀疏和肺灌注不均(马塞克征)14例、肺梗死6例、胸腔积液6例、心包积液4例.结论:64排VCT增强扫描是一种安全、快捷、有效的诊断肺栓塞的无创性检查手段,其检出率高,可作为肺栓塞的首选检查方法.     

64排VCT增强扫描在肺动脉栓塞中的诊断价值

目的:探讨64排容积CT(VCT)增强扫描在肺动脉栓塞诊断中的价值。方法:搜集17例经64排VCT增强扫描确诊的肺动脉栓塞患者的影像资料,所有病例均行多平面重组(MPR)、曲面重组(CPR)、三维容积成像(VRT)及最大密度投影(MIP)等后处理,对血栓的形态、部位、表现形式以及其它相关改变进行归类分析。结果:17例共累及肺动脉及其分支87处,其CT表现直接征象:中心性充盈缺损(轨道征)9处、偏心性或附壁性充盈缺损26处、完全阻塞性充盈缺损(血管截断征)13处;间接征象:肺动脉增宽7例、局限性肺纹理稀疏和肺灌注不均(马塞克征)14例、肺梗死6例、胸腔积液6例、心包积液4例。结论:64排VCT增强扫描是一种安全、快捷、有效的诊断肺栓塞的无创性检查手段,其检出率高,可作为肺栓塞的首选检查方法。     

多层螺旋CT 肺动脉造影在肺动脉栓塞中的诊断价值

目的：探讨多层螺旋CT肺动脉造影（CTPA）对肺动脉栓塞（PE）诊断的价值。方法对临床怀疑有肺动脉栓塞的40例患者进行C T肺动脉造影检查,扫描原始图像传至飞利浦EBW工作站,采用最大密度投影（M IP ）、多平面重建（M PR）、容积再现（VR）等后处理技术,结合薄层原始图像进行综合分析。结果确定肺动脉栓塞16例,其中左右肺动脉栓塞3例,肺叶动脉及肺段动脉同时栓塞6例,左右肺动脉至肺亚段动脉多发栓塞7例。直接征象为动脉管腔内完全或不完全充盈缺损,间接征象为阻塞远端肺组织纹理稀疏,节段性肺梗死灶,胸腔积液等。结论多层螺旋CT肺动脉造影对诊断肺动脉栓塞特异性较高,在无碘过敏等禁忌症情况下安全性高,技术优势明显,能帮助临床作出确定性诊断。     

肺灌注/通气显像与肺动脉造影诊断肺栓塞的对比分析

目的：评价肺灌注／通气显像诊断肿栓塞的价值。方法：回顾性分析45例疑肺栓塞患者的肺核素显像结果，并与肺动脉造影检查对照。结果：肺动脉造影诊断为肺栓塞的患者26例，有180个肺动脉支为充盈缺损，其肺灌注显像示167个节段呈完全肺段性或亚肺段缺损，符合率为92．7％。肺动脉造影显示为86个肺动脉支为部分充盈缺损，肺灌注显像有63个肺段或亚肺段缺损，符合率为73．2％（P＜0．01）。肺核素显像对肺栓塞诊断的灵敏度为92．3％，特异性为84．2％，阳性预测值和阴性预测值均为88．9％。26例肺动脉造影诊断为肺栓塞的患者，有23例行肺通气显像，通气／灌注均不匹配。结论：肺灌注／通气显像对肺栓塞诊断具有重要的临床价值。     

肺灌注/通气显像与肺动脉造影诊断肺动脉栓塞的对比研究

目的评价核素肺通气/灌注(V/Q)显像在肺动脉栓塞(PE)诊断中的价值。方法临床疑有PE患者30例,男女各15例,平均年龄(38.2±13.9)岁。均行胸部X线片检查、核素V/Q显像和肺动脉造影。11例患者在行肺灌注显像时,选择双侧足背静脉注射肺灌注显像剂,同时完成双下肢静脉显像。结果30例患者中22例V/Q显像示不相匹配的肺叶、肺段或多发亚肺段的放射性分布稀疏或缺损,提示为PE;但肺动脉造影证实22例中20例为PE。8例患者的V/Q显像为相匹配的肺叶、肺段或多发亚肺段的稀疏或缺损,提示不是PE,与肺动脉造影结果一致。核素V/Q显像诊断PE的灵敏度为100%（20/20例）,特异性为80.0%（8/10例）,准确性为93.3%（28/30例）。X线胸片和核素下肢静脉显像有助于PE的正确诊断。结论多数PE患者通过核素肺V/Q显像结合X线胸片可以作出明确诊断,少数肺V/Q显像与临床表现不符的患者需行肺动脉造影。     

Magnetic resonance angiography for the primary diagnosis of pulmonary embolism: A review from the international workshop for pulmonary functional imaging

Pulmonary contrast enhanced magnetic resonance angiography (CE-MRA) is useful for the primary diagnosis of pulmonary embolism (PE). Many sites have chosen not to use CE-MRA as a first line of diagnostic tool for PE because of the speed and higher efficacy of computerized tomographic angiography (CTA). In this review, we discuss the strengths and weaknesses of CE-MRA and the appropriate imaging scenarios for the primary diagnosis of PE derived from our unique multi-institutional experience in this area. The optimal patient for this test has a low to intermediate suspicion for PE based on clinical decision rules. Patients in extremis are not candidates for this test. Younger women (< 35 years of age) and patients with iodinated contrast allergies are best served by using this modality We discuss the history of the use of this test, recent technical innovations, artifacts, direct and indirect findings for PE, ancillary findings, and the effectiveness (patient outcomes) of CE-MRA for the exclusion of PE. Current outcomes data shows that CE-MRA and NM V/Q scans are effective alternative tests to CTA for the primary diagnosis of PE.     

64层CT血管成像与肺通气灌注显像诊断肺栓塞的对比研究

目的:通过比较两种无创影像检查为临床诊断肺栓塞提供有指导意义检查方法。方法:64层螺旋CT肺动脉成像和肺通气/灌注显像图像依据相同的诊断标准进行独立的分析。V/Q显像和多层螺旋CT肺动脉成像两种检查方法的判定结果进行相关分析,两者准确性、符合性及不确定性诊断比率的差异采用2检验进行比较。结果:180例患者中CTPA和V/Q显像诊断PE的敏感性、特异性、符合率分别为90.5%对83.8%,91.5%对85.0%,91.1%对84.4%。CTPA和V/Q显像诊断PE的κ值分别为0.680,0.648。结论:疑诊肺栓塞病例中两者皆可作为确诊及排除疑诊肺栓塞病例的检查方法。     

16层螺旋CT血管造影在肺动脉栓塞诊断中的价值

肺动脉栓塞(pulmonary embolism,PE)是内源性或外源性栓子阻塞肺动脉及其分支引起的肺循环障碍的临床病理生理综合征,并发肺出血或坏死者称为肺梗死[1]。PE是一种常见的心血管疾病,它具有发病率高,临床表现缺乏特异性,易漏诊及误诊,未经治疗者死亡率高的特点,达20%~30%,及时诊断治疗者死亡率可降至2%~8%[2]。近年来,尤其是多层螺旋CT血管造影(MSCTA)等先进技术的应用使PE的及时诊断成为可能,本文报告23例PE的MSCTPA表现如下。1材料与方法1.1临床材料本组23例中,男14例,女9例,年龄14~82岁,平均61岁。其中10例有下肢深静脉血栓,4例有…     

64层螺旋CT肺动脉造影在肺动脉栓塞诊断中的应用

目的 探讨64层螺旋CT肺动脉造影(CT pulmonary angiography,CTPA)对肺动脉栓塞(pulmonary embolism,PE)的诊断价值.方法 回顾分析24例肺动脉栓塞患者的64层螺旋CT增强图像,将原始图像复制到EBW4.0工作站,对肺动脉主干及分支进行多平面重建(MPR),最大密度投影(MIP)及容积重建(VR)分析.结果 24例患者中,共检出了76处肺动脉及其分支的栓子.其中,左、右肺动脉主干14处(右主干10处、左主干4处),肺叶动脉24处,肺段动脉26处,亚肺段动脉12处.CT表现为肺动脉主干或分支内混合性、附壁性、中心性充盈缺损,可分为完全性或部分性.结论 64层CTPA具有准确、高效、无创等优点,可直观、立体地观察到肺动脉血栓的大小、分布、范围及类型,是临床诊断及观察疗效的首选方法,有望成为肺动脉栓塞检查的“金标准”.