Prediction of short term outcome of pulmonary embolism: Parameters at 16 multi-detector CT pulmonary angiography

Purpose

To evaluate the accuracy of computed tomography pulmonary angiography (CTPA) parameters, for predicting short-term mortality in patients with acute pulmonary embolism (PE).

Materials and methods

Thirty-two patients with proven PE had CT pulmonary angiography were included in the study. The clot burden using the Qanadli score (QS), and the right ventricular dysfunction (RVD) parameters were assessed on CT by calculating right ventricular/left ventricular (RV/LV) diameter ratios, interventricular septum abnormality, inferior vena cava contrast reflux, azygous vein and superior vena cava measures. Contrast density in pulmonary artery and descending aorta was evaluated for all patients. Patients were followed up for 30 days and then classified as survivors or non survivors.

Results

Thirty-two patients were included in the study, 23 (71.8%) of them were classified as survivors, and the other nine (28.1%) patients died within the first month (non survivors). There was a positive, but weak correlation between the Qanadli score and the short term mortality (P value = 0.05). There was a statistically significant relationship between the RV/LV ratio and PE-related mortality, with a P value < 0.001. Also, there was a good correlation between degree of IVC reflux and PE outcome (P < 0.001). The PA/AO diameter ratio, SVC diameter and azygous vein diameter showed no statistically significant difference between survivors and non survivors.

Conclusions

CTPA findings that may predict short term mortality are the high grades of inferior vena cava reflux, RV/LV diameter ratio more than 1.2, and clot burden >18 according to the Qanadli score and to a lesser degree the interventricular septum abnormality.     

CT pulmonary angiography is the first-line imaging test for acute pulmonary embolism: a survey of US clinicians

RATIONALE AND OBJECTIVES: Our aim is to document current imaging practices for diagnosing acute pulmonary embolism (PE) among physicians practicing in the United States and explore factors associated with these practices. MATERIALS AND METHODS: Between September 2004 and February 2005, we surveyed by mail 855 physicians selected at random from membership lists of three professional organizations. Physicians reported their imaging practices and experiences in managing patients with suspected acute PE during the preceding 12 months. RESULTS: Completed questionnaires were received from 240 of 806 eligible participants (29.8%) practicing in 44 states: 86.7% of respondents believed that computed tomographic pulmonary angiography (CTPA) was the most useful imaging procedure for patients with acute PE compared with 8.3% for ventilation-perfusion (V-P) scintigraphy and 2.5% for conventional pulminary angiography (PA). After chest radiography, CTPA was the first imaging test requested 71.4% of the time compared with V-P scintigraphy (19.7%) and lower-limb venous ultrasound (5.8%). Participants received indeterminate or inconclusive results 46.4% of the time for V-P scintigraphy, 10.6% of the time for CTPA, and 2.2% of the time for PA. CTPA was available around the clock to 88.3% of participants compared with 53.8% for V-P scintigraphy and 42.5% for PA. A total of 68.6% of respondents received CTPA results in 2 hours or less (vs 37.5% for V-P scintigraphy and 22.9% for PA). CTPA also provided an alternative diagnosis to PE or showed other significant abnormalities 28.5% of the time, and these findings frequently altered management. CONCLUSION: US clinicians unequivocally prefer CTPA in patients with suspected acute PE. Reasons for this preference include availability and timely reporting, a lower rate of inconclusive results, and the additional diagnostic capabilities that CTPA can provide.     

Evaluation of peripheral artery stent with 64-slice multi-detector row CT angiography: Prospective comparison with digital subtraction angiography

Purpose

To assess the accuracy of 64-slice multi-detector row computed tomography (MDCT) angiography in the evaluation of peripheral artery in-stent or peristent restenosis, with conventional digital subtraction angiography (DSA) as the reference standard.

Materials and methods

Forty-one patients (30 men, 11 women; mean age, 69.8 ± 9.2 years) with symptomatic peripheral arterial occlusive disease after peripheral artery stenting (81 stented lesions) underwent both conventional DSA and 64-slice MDCT angiography. Each stent was classified as evaluable or unevaluable, and every stent was divided into three segments (proximal stent, stent body, and distal stent), resulting in 243 segments. For evaluation, stenosis was graded as follows: 1, none or slight stenosis (<25%); 2, mild stenosis (25-49%); 3, moderate stenosis (50-74%); 4, severe stenosis or total occlusion (≥75%). Two readers evaluated all CT angiograms with regard to narrowing of in-stent or peristent restenosis by consensus. Results were compared with findings of the DSA.

Results

Of 81 stents, 62 (76.5%) were determined to be assessable. The metal artifact of the gold marker and motion artifact increased uninterpretability of the images of stents. Overall, 24 of 28 in-stent restenosis and 38 of 53 persistent restenosis were correctly detected by MDCT (85.7% and 71.7% sensitivity). In evaluable stents, 21 of 22 in-stent restenoses and 27 of 28 persistent restenosis were correctly detected (95.4% and 96.4% sensitivity). Additionally, as the grade of stenosis increases, the mean level of CT values in the stent lumina decreases linearly accordingly.

Conclusion

64-Slice MDCT has a high accuracy for the detection of significant in-stent or peristent restenosis of assessable stents in patients with peripheral artery stent implantation and therefore can be considered as a valuable noninvasive technique for stent surveillance.     

Assessment of vertebral artery stents using 16-slice multi-detector row CT angiography in vivo evaluation: comparison of a medium-smooth kernel and a sharp kernel

Objectives

To assess the lumen visibility of extracranial vertebral artery stents examined with 16-slice multi-detector row computed tomography (MDCT) angiography in vivo using a medium-smooth kernel (B30s) and a sharp kernel (B60s), and to compare these with digital subtraction angiography (DSA) after stent placement.

Methods

Twenty stents from 20 patients (14 men, 6 women; mean age, 62.7 ± 10.1 years) who underwent CT angiography (CTA) with 16-slice MDCT were retrospectively analyzed. In CT angiograms using a B30s and a B60s, the lumen diameters and CT attenuations of the stented vessels were measured three times by three observers, and artificial luminal narrowing (ALN) was calculated. To assess measurement reliability on CT angiograms, the intraclass correlation coefficient (ICC) was used. DSA served as the reference standard for the in-stent luminal measurements on CT angiography. The median interval between CT angiography and DSA was 1 day (range 1–10).

Results

For interobserver reliability, intraclass correlation coefficients for the lumen diameters on CT angiograms with a B30s and a B60s were 0.90 and 0.96, respectively. The lumen diameters on CT angiograms using a B30s were consistently smaller than that on CT angiograms using a B60s (p < 0.01). The mean ALN was 37 ± 7% on CT angiograms using a B30s and 25 ± 9% on CT angiograms using a B60s. The mean CT attenuation in in-stent lumen was 347 ± 55 HU on CT angiograms using a B30s and 295 ± 46 HU on CT angiograms using a B60s. The ALN and CT attenuation within the stented vessels between CT angiograms using a B30s and a B60s was significant (p < 0.01).

Conclusions

16-slice MDCT using a sharp kernel allows good visualization of the stented vessels and is useful in the assessment of vertebral artery stent patency after stent placement.     

CT和MR血管成像诊断急性肺栓塞的Meta分析

目的：应用 Meta 分析法,以 DSA 为金标准,探讨 CT 肺动脉成像（CTPA）和磁共振肺血管成像（MRPA）对肺动脉栓塞（PE）的诊断价值。方法：检索 Cochrane 图书馆、Medline 数据库、Springerlink 数据库及 Ovid 循证医学数据库中1994～2013年发表的英文文献以及知网数据库和万方医学数据库中1994～2013年发表的中文文献,按照 Cochrane 协作网推荐的诊断性实验的纳入标准,严格筛选与“CTPA 和／或 MRPA 诊断急性 PE”相关的文献。在符合条件的文献中提取诊断信息（包括真阳性值、假阳性值、真阴性值、假阴性值）和其它相关数据。采用 Stata 12软件和 Meta-disc 1．4软件对纳入文献行统计学处理,包括异质性检验,计算敏感度和特异度及其95％可信区间,选择相应的效应模型予以加权定量合并,绘制汇总的工作特征曲线（SROC）,最后进行敏感性分析。结果：按照纳入标准共获取有效文献17篇,其中与 CTPA相关的文献10篇,与 MRPA 相关的文献7篇。17篇文献均满足诊断性研究质量评价工具（QUADAS）中提出的14项标准中的10项以上。CTPA 及 MRPA 两组中的相关研究均有异质性,按照随机效应模型对纳入文献进行汇总分析。结果显示,CTPA 诊断肺栓塞的敏感度、特异度及各自的95％可信区间分别为0．78（0．74～0．82）和0．90（0．87～0．92）,MR-PA 为0．86（0．79～0．92）和0．97（0．94～0．99）,SROC 下面积分别为94％和98％。结论：CTPA 和 MRPA 对急性肺栓塞的诊断均具有很高的价值,两种方法的诊断特异度均很高,作为诊断肺栓塞的无创性检查方法可基本替代 DSA 检查。     

Prospective comparison of helical CT and MR imaging in clinically suspected acute pulmonary embolism

The purpose of this study is to compare sensitivity and specificity of helical CT and MR imaging for detecting acute pulmonary embolism (PE). Patients who were suspected clinically of having PE were randomly assigned to undergo either helical contrast-enhanced CT or gradient-echo MR (if one modality was contraindicated, the patient was assigned to the other). Patients were considered to have PE if they had: (1) high-probability V-Q scan and high clinical probability of PE; or (2) pulmonary angiogram positive for PE. Patients were considered not to have PE if they had either: (1) normal V-Q scan; (2) low probability V-Q scan and low clinical probability of PE; or (3) pulmonary angiogram negative for PE. The CT and MR images were read randomly and independently by five radiologists with varying levels of CT and MR experience. Twenty eight patients underwent CT and 25 MR. A total of 21 patients underwent pulmonary angiography (6 had PE, 15 did not have PE). Of the other 32 patients, 15 had high probability scan/high clinical probability and 17 had low probability scan/low clinical probability. For the five observers, the average sensitivity of CT was 75% and of MR 46%; the average specificity of CT was 89% and of MR 90%. Experience with vascular MR and enhanced CT influenced diagnostic accuracy. For the two vascular MR experts, average sensitivity and specificity of MR were 71% and 97%, and of CT 73% and 97%. In this pilot study, when CT and MR were interpreted with comparable expertise, they had similar accuracy for detecting pulmonary embolism.     

CT肺动脉成像结合D-二聚体对急诊肺栓塞病人的诊断价值

目的分析以胸痛为主要表现于急诊就诊的病人采用CT肺动脉成像(CTPA)结合D-二聚体检测肺栓塞的临床应用价值。方法回顾性分析自2015年1月1日—2017年6月30日于急诊以胸痛就诊并行CTPA检查的病人155例,其中男83例,女72例,年龄13~84岁,平均(55±16)岁。分析和记录肺栓塞的有无及其发生率,分析无肺栓塞病人伴发的有临床诊疗意义的病变。记录纳入病人的D-二聚体值。采用Fisher精确检验分析D-二聚体阳性组和阴性组CTPA上肺栓塞的检出率;采用独立样本t检验比较D-二聚体异常组CTPA上肺栓塞病人和非肺栓塞病人的D-二聚体值。以CTPA诊断为参考标准,评估D-二聚体在诊断肺栓塞中的价值。结果155例病人中,50例(32.3%)病人经CTPA诊断为肺栓塞,105例(67.7%)病人无肺栓塞。152例病人进行了D-二聚体测量。按照常规D-二聚体参考值0.5 mg/d L为阳性阈值,其中二聚体值阳性128例,阴性24例。24例D-二聚体值阴性者CTPA上均无肺栓塞(0/24),CTPA上有肺栓塞的50例病人(50/128,39.1%)的D-二聚体值为阳性,78例D-二聚体阳性者的CTPA上无肺栓塞,2组肺栓塞检出率的差异有统计学意义(Fisher精确检验,P<0.001)。D-二聚体值阳性组中,50例病人于CTPA上诊断为肺栓塞,78例CTPA上无肺栓塞,两者的平均D-二聚体值差异无统计学意义[分别为(6.11±5.59)mg/d L和(5.26±6.67)mg/d L,t=0.741,P=0.460]。以CTPA检测结果为参考,D-二聚体诊断肺栓塞的敏感度、特异度、阳性预测值、阴性预测值分别为100%、23.5%、39.1%、100%。结论本研究提示结合D-二聚体的测定推荐CTPA检查有助于进一步提高肺栓塞检测的阳性率。     

Multislice CT imaging of pulmonary embolism

In recent years CT has been established as the method of choice for the diagnosis of central pulmonary embolism (PE) to the level of the segmental arteries. The key advantage of CT over competing modalities is the reliable detection of relevant alternative or additional disease causing the patient's symptoms. Although the clinical relevance of isolated peripheral emboli remains unclear, the alleged poor sensitivity of CT for the detection of such small clots has to date prevented the acceptance of CT as the gold standard for diagnosing PE. With the advent of multislice CT we can now cover the entire chest of a patient with 1-mm slices within one breath-hold. In comparison with thicker sections, the detection rate of subsegmental emboli can be significantly increased with 1-mm slices. In addition, the interobserver correlation which can be achieved with 1-mm sections by far exceeds the reproducibility of competing modalities. Meanwhile use of multislice CT for a combined diagnosis of PE and deep venous thrombosis with the same modality appears to be clinically accepted. In the vast majority of patients who receive a combined thoracic and venous multislice CT examination the scan either confirms the suspected diagnosis or reveals relevant alternative or additional disease. The therapeutic regimen is usually chosen based on the functional effect of embolic vascular occlusion. With the advent of fast CT scanning techniques, also functional parameters of lung perfusion can be non-invasively assessed by CT imaging. These advantages let multislice CT appear as an attractive modality for a non-invasive, fast, accurate, and comprehensive diagnosis of PE, its causes, effects, and differential diagnoses.     

Accuracy of CT angiography versus pulmonary angiography in the diagnosis of acute pulmonary embolism: evaluation of the literature with summary ROC curve analysis

RATIONALE AND OBJECTIVES: The authors performed this study to estimate, by using published data, the sensitivity and specificity of computed tomographic (CT) angiography in the evaluation of suspected acute pulmonary embolism (PE). MATERIALS AND METHODS: Summary receiver operating characteristic (ROC) curve analysis was used to determine the sensitivity and specificity of CT angiography in the diagnosis of acute PE. Pulmonary angiography was used as the diagnostic standard of reference. The authors reviewed the results of 11 independent studies published in the English-language literature between January 1992 and June 1999. RESULTS: The sensitivity of CT angiography in the diagnosis or exclusion of PE in the central pulmonary arteries (to the level of the segmental pulmonary arteries) ranged from 0.74 to 0.81 on the basis of specificities of 0.89-0.91. The sensitivity of CT angiography in the diagnosis or exclusion of PE in all pulmonary arteries (to the level of the subsegmental pulmonary arteries) was 0.68 on the basis of a specificity of 0.91. CONCLUSION: On the basis of the studies in the current literature, most of which used 5.0-mm collimation and single-detector CT, CT angiography may be less accurate in the diagnosis of PE than previously reported. With improvements in data acquisition, particularly the use of thinner section collimation and multidetector CT, and in the increased use of workstations for data analysis, the accuracy and utility of CT angiography will require continued investigation.     

急性肺动脉栓塞患者CT阻塞指数与缺氧严重程度的相关性研究

目的:评价急性肺动脉栓塞患者CT阻塞指数(CTOI)与缺氧严重程度的相关性。方法:对24例急性肺动脉栓塞患者(栓塞组)的CT肺动脉造影(CTPA)资料进行回顾性分析,了解肺动脉CTOI与血氧饱和度(SO2)的相关性;以30例无栓塞的患者作为对照组,了解栓塞患者及无栓塞患者的SO2是否有差异;以SO2值94%为标准,将肺动脉栓塞患者分为缺氧组(<94%)和非缺氧组(≥94%),了解引起缺氧的肺动脉栓塞程度。结果:肺动脉栓塞组和对照组的SO2分别为:(89.96±7.68)%和(97.53±5.26)%,肺动脉栓塞组的SO2明显低于对照组(P<0.05);CTOI与SO2之间呈明显负相关(r=0.45,P=0.03),随着CTOI的增加,SO2降低越明显;肺动脉栓塞患者中,非缺氧组CTOI值的95%可信区间为0%～49.20%,缺氧组CTOI值的95%可信区间为39.88%～100%,CTOI值为40%～50%时,患者处于氧供不足的临界状态。结论:急性肺动脉栓塞患者CTOI与缺氧严重程度具有相关性,SO2值低于94%时,提示肺动脉栓塞超过约50%。     

Reproducibility of multi-detector spiral computed tomography in detection of sub-segmental acute pulmonary embolism

The aim of this study was to evaluate the inter-observer and intra-observer agreement of the diagnosis of sub-segmental acute pulmonary embolism (PE) in an inpatient population explored by 16 slice multi-detector spiral computed tomography (MDCT). Four hundred consecutive inpatients were referred for MDCT for the clinical suspicion of acute PE. One hundred and seventy seven (44.2%) had a known cardio-respiratory disease at the time of examination. Inter-observer and intra-observer agreements for the diagnosis of acute PE and of sub-segmental acute PE were assessed blind and independently by three experienced readers and by kappa statistics. Seventy-five patients were diagnosed as having acute PE findings (19.5%), and clots were located exclusively within sub-segmental arteries in nine patients (12%). When clots were limited to sub-segmental or more distal branches of the pulmonary arteries, kappa values were found to be moderate (0.56) to very good (0.85) for the diagnosis of sub-segmental acute PE, whereas for the diagnosis of acute PE in the whole population, kappa values ranged from 0.84 to 0.97. Intra-observer agreement was found to be perfect (kappa=1). MDCT is a reproducible technique for the diagnosis of sub-segmental acute PE as well as for acute PE. In this inpatient population, sub-segmental acute PE was not a rare event.     

CT imaging in acute pulmonary embolism: diagnostic strategies

Computed tomography pulmonary angiography (CTA) has increasingly become accepted as a widely available, safe, cost-effective, and accurate method for a quick and comprehensive diagnosis of acute pulmonary embolism (PE). Pulmonary catheter angiography is still considered the gold standard and final imaging method in many diagnostic algorithms. However, spiral CTA has become established as the first imaging test in clinical routine due to its high negative predictive value for clinically relevant PE. Despite the direct visualization of clot material, depiction of cardiac and pulmonary function in combination with the quantification of pulmonary obstruction helps to grade the severity of PE for further risk stratification and to monitor the effect of thrombolytic therapy. Because PE and deep venous thrombosis are two different aspects of the same disease, additional indirect CT venography may be a valuable addition to the initial diagnostic algorithm—if this was positive for PE—and demonstration of the extent and localization of deep venous thrombosis has an impact on clinical management. Additional and alternate diagnoses add to the usefulness of this method. Using advanced multislice spiral CT technology, some practitioners have advocated CTA as the sole imaging tool for routine clinical assessment in suspected acute PE. This will simplify standards of practice in the near future.     

ECG-gated multislice spiral CT for diagnosis of acute pulmonary embolism

AIM: The purpose of this study was to determine the feasibility of echocardiogram (ECG)-gated multi-slice CT angiography (MCTA) in patients with clinical suspicion of acute venous thromboembolism (VTE), to investigate the effect of ECG-gating on cardiac motion artefacts, and to determine the diagnostic reader agreement of ECG-gated MCTA in comparison with conventional MCTA. MATERIALS AND METHODS: Forty-eight consecutive patients were prospectively enrolled and randomly underwent ECG-gated (n=25, group 1) or non-ECG-gated (n=23, group 2) eight-slice pulmonary MCTA. Image data were evaluated by three independent chest radiologists with respect to the presence or absence of emboli at different arterial levels (main, lobar, segmental, and subsegmental arteries), and with regard to cardiac motion artefacts. Statistical tests used to calculate inter-observer agreement were weighted kappa statistics, extended kappa statistics and confidence indices indicating three-reader agreement accuracy. RESULTS: Twenty-seven patients (56.3%) were diagnosed to have pulmonary embolism (13 from group 1, 14 from group 2). Cardiac motion artefacts were significantly more frequent in group 2 (70% in group 2 versus 13% in group 1, p=0.0001). The overall diagnostic agreement was excellent with both MCTA techniques (three-reader confidence index for all vascular territories: 0.76 and 0.84 for groups 1 and 2, respectively (extended kappa=0.69 and 0.78, respectively); three-reader confidence index for diagnosis of VTE: 0.94 and 0.85 for groups 1 and 2, respectively (extended kappa=0.91 and 0.73, respectively), weighted kappa=0.81-0.83 and 0.92-0.95 for groups 1 and 2, respectively, and did not differ significantly between the two groups. In addition there was no significant difference of inter-observer agreement in either group at any assessed pulmonary arterial level. CONCLUSION: ECG-gated pulmonary MCTA is feasible in patients with clinical suspicion of VTE. However, ECG-gated image acquisition did not influence the diagnostic reader agreement accuracy and inter-observer agreement of MCTA. Hence, it does not appear to be advantageous for the MCTA diagnosis of pulmonary embolism.     

双能量CT评估急性肺栓塞治疗疗效

目的:探讨双能量CT在急性肺栓塞治疗疗效评估中的价值.方法:30例急性肺栓塞患者纳入本研究,所有患者在治疗前后均进行了双能量CT检查.比较治疗前后肺动脉栓子数目、肺动脉阻塞指数、右心室/左心室直径比值、肺动脉主干/升主动脉直径比值、双能量CT肺灌注缺损积分、全肺及左右肺的强化值和相对强化率.结果:30例患者中29例在治疗后肺动脉内栓子完全(n=18)或部分缓解(n=11),1例患者肺栓塞加重.双能量CT肺灌注成像显示治疗后5例患者无灌注缺损,25例患者有不同程度灌注缺损.30例患者治疗前后肺栓塞的位置、数目、肺动脉阻塞积分和双能量CT肺灌注缺损评分差异有统计学意义(P＜0.05),而肺动脉主干/同层面升主动脉直径比值、右心室/左心室直径比值、全肺及左右肺的强化值和相对强化率差异无统计学差别(P＞0.05).结论:双能量CT可用于急性肺栓塞治疗疗效的评估,可为临床治疗方案的制定及调整提供重要信息.     

基于第3代双源CT双低检查技术在肺栓塞成像的临床应用研究

目的 探讨第3代双源CT大螺距70 kV联合超低对比剂用量16 ml在肺栓塞低辐射剂量成像的临床应用价值。方法 将83例临床可疑肺栓塞行CT肺动脉成像患者,按随机数表法,分为两组：常规组,36例,管电压100 kV,螺距1.0,对比剂总量60 ml;双低组,47例,管电压70 kV,螺距2.2,对比剂总量16 ml。记录两组的容积CT剂量指数（CTDI_vol）和剂量长度乘积（DLP）以计算有效剂量（E）,测量各级肺动脉增强CT值、背景噪声及肌肉CT值以计算信噪比（SNR）、对比噪声比（CNR）。两组的总体图像质量和上腔静脉引起的线束硬化伪影均采取3级评分进行主观评价。结果 两组患者之间性别、年龄、身高、体重、体质量指数（BMI）、肺栓塞比例及各级肺动脉增强CT值差异均无统计学意义（P>0.05）。双低组E为（0.76±0.13）mSv,常规组为（1.91±0.54）mSv,两组比较差异有统计学意义（Z=-5.23,P<0.001）。双低组背景噪声高于常规组（Z=-4.99,P<0.001）,且SNR和CNR均低于常规组（Z=-4.56、-4.48,P<0.001）,但两组总体图像质量主观评分差异无统计学意义（P>0.05）,且双低组上腔静脉引起的线束硬化伪影评分（1.34±0.60）低于常规组（2.94±0.23）,两组比较差异有统计学意义（Z=-5.15,P<0.001）。结论 第3代双源CT大螺距70 kV联合16 ml超低对比剂用量,可以显著降低对比剂线束硬化伪影对右肺动脉、右肺上叶动脉的干扰,保证肺栓塞诊断图像质量,并大幅度降低辐射剂量约60%,同时减少73%对比剂总量。     

Survey on the use of pulmonary scintigraphy, spiral CT and conventional pulmonary angiography for suspected pulmonary embolism in the British Isles

AIM: To determine current clinical practice in the radiological diagnosis of acute pulmonary embolism and assess the use of spiral volumetric computed tomography. METHOD: A survey of 327 acute hospitals including cardiothoracic and orthopaedic tertiary referral centres was undertaken to assess current utilization of lung scintigraphy, spiral computed tomography and pulmonary angiography in the investigation of suspected pulmonary embolism. Responses were received from 215/327 (66%) centres. RESULTS: Lung scintigraphy was provided by 208 hospitals (144 on-site and 64 off-site). Spiral CT services were provided by 111 (52%) hospitals (on- or off-site), 142 (66%) units had access to angiographic facilities. Sixty-three centres out of 215 (29%) offered both on-site lung scintigraphy and spiral CT while only 41/215 (19%) hospitals were able to undertake all three tests on-site. On average, 501 perfusion (Q) or ventilation-perfusion (V/Q) scintigrams were performed per hospital per year with 26 spiral CT studies and just 4.6 pulmonary angiograms. CONCLUSION: These data suggest that lung scintigraphy is frequently the only imaging test in patients other than chest radiography, despite the large number of indeterminate results reported in most series.     

Comparison of doses for pulmonary embolism detection with helical CT and pulmonary angiography

The objective of this study was to compare the radiation exposure delivered by helical CT and pulmonary angiography (PA) for the detection of pulmonary embolism (PE), with an anthropomorphic phantom. A preliminary survey defined a representative standard procedure for helical CT and PA (n=148) by choosing the exposure settings most frequently used. Then, radiation doses were measured with thermoluminescent dosimeters TLD 100 (Lif) introduced into the depth of an anthropomorphic phantom. Average doses were approximately five times smaller with helical CT than with PA (6.4±1.5 and 28±7.6 mGy, respectively). The most important doses were abreast the pulmonary apex for CT, and abreast the pulmonary arteries for PA. Compared with PA, helical CT dose distribution was relatively uniform (10–13 mGy). Finally, concerning abdomen and pelvis, doses were more important for PA than for CT scan (0.06–2.86 and 0.2–11.5 mGy, respectively). For the diagnostics of PE, radiation exposure is five times smaller with helical CT than with pulmonary angiography.     

320层动态容积CT血管成像在肺动脉栓塞中的诊断价值

目的探讨320层动态容积CT血管成像在诊断肺动脉栓塞中的价值。方法回顾性分析30例临床确诊为肺动脉栓塞的320层动态容积CT肺动脉成像资料,并用最大密度投影(MIP)、多平面重组(MPR)、容积再现(VR)等方法显示肺动脉。结果 30例患者中,其中左右肺动脉栓塞有15支,叶肺动脉栓塞30支,段及亚段肺动脉栓塞60支。偏心型45支,闭塞型40支,中央型12支,附壁环形型5支。结论 320层动态容积CT肺动脉成像可作为肺动脉栓塞诊断的首选方法。     

肺灌注显像与磁共振肺血管成像对急性肺栓塞诊断价值的比较研究

目的 对比研究单光子发射计算机断层显像(SPECT)和磁共振肺血管成像(MRPA)评估对急性肺栓塞(APE)的临床诊断价值.方法 检索Cochrane图书馆、Medline数据库、Springerlink数据库及ovid循证医学数据库2004-2013年的英文文献,以及中国期刊网包括中国知网、万方医学数据库以及Google学术搜索2004 2013年的中文文献,按照cochrane协作网推荐的诊断实验纳入标准筛选文献,提取纳入研究的诊断信息(真阳性值、假阳性值、真阴性值、假阴性值).采用Stata12软件和Meta-disc1.4软件对纳入文献行统计学处理,包括异质性检验,计算灵敏度和特异度及其95％可信区间,并选择相应的效应模型予以加权定量合并,绘制汇总工作特征曲线(SROC),最后行敏感性分析.结果 按照纳入标准共获取文献16篇,其中纳入SPECT诊断肺栓塞(PE)文献9篇,MRPA文献7篇.都满足诊断性研究质量评价工具(QUADAS) 14条目中的10条以上,按照随机效应模型对纳入文献进行汇总分析.结果显示,以多排CT(MDCT)为金标准,SPECT诊断PE的敏感度、特异度和95％可信区间分别为0.86(0.83～0.88)和0.94(0.93～0.95),MRPA为0.85(0.80～0.89)和0.98(0.97～0.99),SROC曲线下面积(AUC)分别为96％和99％.结论 基于CTPA诊断PE为辐射暴露检查方法,汇总分析非辐射暴露检查SPECT和MRPA评估PE的诊断价值,二者诊断PE的灵敏度及特异度均很高,其诊断价值无明显差异,SPECT和MRPA检查方法可作为PE诊断辐射暴露禁忌的重要替代检查.     

CTPA for the diagnosis of acute pulmonary embolism during pregnancy

CT pulmonary angiography (CTPA) has been suggested by the Fleischner society as the first test following a negative leg ultrasound in pregnant patients with suspected pulmonary embolism. This editorial discusses the use of CTPA as a diagnostic tool in pregnant women and comments on the need for specifically adapting CT protocols during pregnancy in the light of new research describing a substantial number of non-diagnostic examinations in pregnant women if routine scanning protocols are used for CTA of the pulmonary arteries. Potential reasons for these high numbers of insufficient examinations are physiological changes occurring during pregnancy that lead to a hyperdynamic circulation, which reduces average enhancement of the pulmonary vasculature. In addition, there are possible breathing-related effects that include an increased risk for Valsalva manoeuvre with devastating effects for pulmonary vascular enhancement. Techniques to overcome these problems are discussed: bolus triggering with short start delays, high flow rates or high contrast medium concentration, preferential use of fast CT systems and the use of low kVp CT techniques. CT data acquisition during deep inspiration should be avoided and shallow respiration may be considered as an alternative to suspended breathing in this patient group. All these factors can contribute to optimization of the quality of pulmonary CTA in pregnant patients. It is time now to adapt our protocols and provide optimum care for this sensitive patient group.