Role of helical CT in detecting right ventricular dysfunction secondary to acute pulmonary embolism

OBJECTIVE: The purpose of this study was to evaluate the role of helical CT in detecting right ventricular dysfunction (RVD) after acute pulmonary embolism (PE). METHODS: This was a retrospective study consisting of 25 patients with CT scans positive for acute pulmonary embolism who had either follow-up echocardiography (23 patients) or pulmonary angiography (2 patients). CT scans were reviewed for findings suggestive of RVD. Scans were considered positive for RVD if the right ventricle (RV) was dilated or if the interventricular septum was deviated towards the left ventricle. Results were then correlated with the results of echocardiography or pulmonary angiography to estimate the sensitivity and specificity of CT in detecting RVD associated with PE. RESULTS: Within this group of 25 patients with PE, CT demonstrated sensitivity of 78% (7/9), specificity of 100% (16/16), and positive predictive value of 100% (7/7) in detection of RVD. CONCLUSION: CT may be useful in detecting RVD in patients with acute PE.     

急性肺血栓栓塞症患者右心功能不全与栓塞范围的相关性研究

目的 明确急性肺血栓栓塞症(PTE)患者肺栓塞(PE)范围与右心功能不全的关系,探讨利用PE范围诊断右心功能不全的可行性.方法 明确诊断为急性PTE的348例患者中,被超声心动图检查诊断为右心功能不全212例和右心功能正常136例.348例急性PTE患者均进行肺通气/灌注(V/Q)显像,用SPSS 11.5软件对PE范围与右心功能进行χ~2检验、直线相关分析及受试者工作特征(ROC)曲线分析.结果 PE范围积分(1～36,11.4±7.1)与右心功能不全参数[右心室/左心室前径比值(RVD/LVD)为0.52±0.22、右心室/左心室横径比值(RVTD/LVTD)为0.88±0.26、三尖瓣返流压差(TRPG)为(31.93±21.79)mm Hg(1 mm Hg=0.133 kPa)和右心室室壁运动幅度(RVAWM)为(5.77±1.99)mm]呈明显相关(r=0.32,0.45,0.38,-0.37,P均<0.001),右心功能不全组患者的PE范围(3～36,15.1±6.3)明显高于右心功能正常组(1～15,5.6±3.3;χ~2=445.93,P<0.001);PE范围诊断右心功能不全的ROC曲线下面积为0.986,Z>2.58,P<0.01.结论 PIE患者右心功能状况与栓塞范围明显相关,PE范围对右心功能的诊断具有重要的参考价值.     

Computed tomography evaluation of right heart dysfunction in patients with acute pulmonary embolism

PURPOSE: To evaluate the role of qualitative assessment of right heart dysfunction on multidetector computed tomography (CT) in patients with acute pulmonary embolism. METHODS: Seventy-four consecutive adults with pulmonary embolism diagnosed on multidetector nongated CT were identified between July 2002 and March 2004. There were 47 women and 27 men, with a mean age of 62 years. Each CT scan was jointly reviewed by 2 of 3 reviewers in consensus. The CT scans were qualitatively assessed for dilatation of the right ventricle and the position of the interventricular septum. Scans were considered positive for right heart dysfunction if, on visual integration of multiple axial images, the right ventricle was dilated or the interventricular septum was straightened or bowed into the left ventricle. The extent of pulmonary vascular obstruction was graded using the CT clot burden scoring system. Reports of echocardiograms (n = 30) were reviewed when available. The sensitivity and specificity of CT and echocardiography in demonstrating right heart dysfunction were calculated and compared using pulmonary vascular obstruction of > or =30% as the reference standard. RESULTS: Sixty-six percent (49 of 74 patients) with pulmonary embolism had right heart dysfunction on CT, with right ventricular dilatation in 38 patients and septal straightening or bowing in 44 patients. Forty-nine percent (36 of 74 patients) had pulmonary vasculature obstruction of > or =30%. There was a significant difference between the mean clot burden of patients with (12.8) and without (7.5) right heart dysfunction on CT (P = 0.0021). The sensitivity and specificity of CT in demonstrating right heart dysfunction were 81% (29 of 36 patients) and 47% (18 of 38 patients), respectively. Forty-one percent (30 of 74 patients) had technically adequate echocardiograms within 48 hours of CT. Fifty-seven percent (17 of 30) of the echocardiograms were positive for right heart dysfunction. There was no significant difference between the mean clot burden of patients with (12.7) and without (10.3) right heart dysfunction on echocardiography. Echocardiography had a sensitivity of 56% (10 of 17 patients) and a specificity of 42% (5 of 13 patients) in demonstrating right heart dysfunction. CONCLUSION: Qualitative assessment of the cardiac chambers is a quick and practical means of evaluating for right heart dysfunction on CT. Computed tomography findings of right heart dysfunction in patients with acute pulmonary embolism compare favorably with echocardiography and correlate with a higher mean pulmonary arterial clot burden. Because most patients do not undergo echocardiography, chest CT often provides the only opportunity to evaluate for right heart dysfunction in patients with acute pulmonary embolism.     

超声心动图评价急性肺栓塞疗效的价值

目的：探讨超声心动图技术对急性肺栓塞治疗效果的评价作用。方法选择我院诊治的急性肺栓塞48例,分别于治疗前,治疗后3、6、12个月做超声心动图检查,测量指标包括右室横径（RVD）、左室横径（LVD）、右房横径（RAD）、左房横径（ LAD）、肺动脉主干内径（ MPAD）、三尖瓣反流压差（ PGTR）、计算右房横径/左房横径（ RATD/LATD）、右室横径/左室横径（ RVD/LVD）及肺动脉收缩压（ SPAP）。比较以上指标在不同时点的变化。结果在溶栓和（或）抗凝治疗3个月时,SPAP [（38．64±11．33）vs（49．86±19．61）]、RA/LA[（1．01±0．28）vs（1．11±0．33）]与治疗前比较,改善最为明显（均P＜0．01）;至6个月、12个月时,改善幅度变小。在溶栓和（或）抗凝治疗3、6、12个月时,RV/LV与治疗前比较,均有明显改善（ P＜0．01或P＜0．05）;而MPAD、LVEF在治疗前后,以及随诊观测中均没有变化,差异无统计学意义（P＞0．05）。全部患者随访12个月后,4例进展为慢性血栓栓塞性肺动脉高压（ chronic thromboembolic pulmonary hypertension ,CTEPH）。结论超声心动图可以作为评价急性肺栓塞疗效的无创实用技术。     

CT angiography findings of the left atrium and right ventricle in patients with massive pulmonary embolism

OBJECTIVE: The purpose of this study was to show the imaging findings of the left atrium and right ventricle on CT angiography in patients with massive pulmonary embolism. CONCLUSION: Massive pulmonary embolism can cause abrupt acute pulmonary arterial hypertension, right ventricular dysfunction, and decrease in left ventricular preload. Patients with these findings on CT angiography can have a poorer prognosis than those without these imaging findings. Consequently, recognizing anatomic changes such as right ventricular dilation or septal bowing, decrease in size of left atrium and pulmonary veins (a manifestation of decreased pulmonary venous return) would be useful for risk stratification at the time of massive pulmonary embolism.     

Spiral computed tomographic pulmonary angiography for investigating suspected pulmonary embolism: clinical outcomes.

PURPOSE: To assess the clinical outcomes of patients who were suspected of having acute pulmonary embolism and underwent spiral computed tomographic pulmonary angiography (CTPA) for diagnosis. METHODS: We evaluated the clinical outcomes of 62 patients with suspected pulmonary embolism; 82 CTPA scans were performed in a 15-month period. Clinical outcomes were recorded for all patients for a minimum of 3 months. RESULTS: Acute pulmonary embolism was diagnosed and treated in 11 (18%) of the 62 patients evaluated via CTPA. Scans of the other 51 (82%) patients were negative for pulmonary embolism. Seven (14%) of these patients died during the 3-month follow-up period; pulmonary embolism was considered to be a contributing factor in 1 of these deaths. Seven (14%) of the 51 patients were lost to follow-up, and 37 (74%) showed no evidence of disease at least 3 months after a negative CTPA study. Despite the presence or absence of an acute pulmonary embolism, an alternate or additional diagnosis was made on 32 (52%) CTPA scans. CONCLUSION: Spiral CTPA can be effectively used to rule out clinically significant pulmonary emboli and also serves to provide alternate diagnoses in patients who do not have a pulmonary embolism.     

MSCTPA对肺栓塞患者右心功能的诊断价值

目的以超声心动图作为诊断右心功能的标准,探讨64层CT肺血管造影(CTPA)对肺栓塞患者右心功能的诊断价值。方法前瞻性收集了临床疑诊肺栓塞的41例行CTPA检查的患者,阳性组根据右心功能、肺动脉栓塞部位及肺动脉压力指数分组,薄层数据进行最大密度投影(MIP)、多平面重建(MPR)和容积再现(VRT),分析各组数据中右心功能参数的差异。结果 41例患者中肺栓塞阳性24例,阴性17例,CTPA诊断右心功能不全13例,超声心动图诊断右心功能不全11例。以超声心动图为标准,64层CTPA诊断右心功能不全的灵敏度为76.9%,特异度为90.9%,阳性预测值90.9%,阴性预测值76.9%,Kappa值为0.669,诊断具有中度一致性。对于主肺动脉干(PA)、升主动脉(Aorta)、上腔静脉(SVC)、奇静脉(AV)、冠状静脉窦(CS)、PA/Aorta比、LVd、RVd及RVd/LVd比之间比较,第一组中差异有统计学意义的指标有PA、PA/Aorta比,LVd、RVd及RVd/LVd,CS;第二组中差异均无统计学意义;第三组中,差异有统计学意义的指标有PA/Aorta比。结论 MSCTPA及其后处理重建技术可以在诊断肺栓塞的同时对心功能作出评价。     

超声检查在急性肺栓塞诊断中的应用价值

目的 探讨超声检查在急性肺栓塞诊断中的应用价值。方法 对临床综合诊断为急性肺栓塞的15例病人行超声心动图检查，综合分析。结果 经超声心动图检查15例患者，发现右房内血栓1例，肺动脉内血栓1例。15例均有右心负荷过重表现，伴有不同程度的三尖瓣返流，返流速度加快，肺动脉压明显增高。7例发现下肢深静脉内血栓。结论 超声心动图在肺动脉栓塞病人的筛查、评价患者的右心功能及疗效方面有重要价值。     

Correlation of CT angiographic pulmonary artery obstruction scores with right ventricular dysfunction and clinical outcome in patients with acute pulmonary embolism

Objective

To correlate CTA pulmonary artery obstruction scores (OS) with right ventricular dysfunction (RVD) and clinical outcome in patients with acute pulmonary embolism (PE).

Materials and methods

In a prospective study of 50 patients (66 ± 12.9 years) with PE pulmonary artery OS (Qanadli, Mastora, and Mastora central) were assessed by two radiologists. To assess RVD all patients underwent echocardiography within 24 h. Furthermore, RVD on CT was assessed by calculating the right ventricular/left ventricular (RV/LV) diameter ratios on transverse (RV/LVtrans) and four-chamber views (RV/LV4ch) as well as the RV/LV volume ratio (RV/LVvol). OS were correlated with RVD and the occurrence of adverse clinical outcomes (defined as death, need for intensive care treatment, or cardiac insufficiency ≥NYHA III).

Results

Mean Mastora, Qanadli, and Mastora central OS were 26.4 ± 17.7, 12.6 ± 9.9 and 7.5 ± 9, respectively. Echocardiography demonstrated moderate and severe RVD in 10 and 5 patients, respectively. Patients with moderate and severe RVD showed significantly higher Mastora central scores than patients without RVD (14 ± 10.8 vs. 5.9 ± 7.8 [p = 0.05]; 17.6 ± 13.2 vs. 5.9 ± 7.8 [p = 0.038]). A relevant correlation (i.e. r ≥ 0.6) between OS and CT parameters for RVD were only found for the Mastora score and the Mastora central score (RV/LV4ch: r = 0.61 and 0.68, RV/LVvol: r = 0.61 and 0.6). 18 patients experienced an adverse clinical outcome. None of the OS differed significantly between patients with and without adverse clinical outcome.

Conclusion

Pulmonary artery obstruction scores can differentiate between patients with and without RVD. However, in this study, obstruction scores were not correlated to adverse clinical outcome.     

Logistic regression model for identification of right ventricular dysfunction in patients with acute pulmonary embolism by means of computed tomography

Purpose

Diagnosis of right ventricular dysfunction in patients with acute pulmonary embolism (PE) is known to be associated with increased risk of mortality. The aim of the study was to calculate a logistic regression model for reliable identification of right ventricular dysfunction (RVD) in patients diagnosed with computed tomography pulmonary angiography.

Material and methods

Ninety-seven consecutive patients with acute pulmonary embolism were divided into groups with and without RVD basing upon echocardiographic measurement of pulmonary artery systolic pressure (PASP). PE severity was graded with the pulmonary obstruction score. CT measurements of heart chambers and mediastinal vessels were performed; position of interventricular septum and presence of contrast reflux into the inferior vena cava were also recorded. The logistic regression model was prepared by means of stepwise logistic regression.

Results

Among the used parameters, the final model consisted of pulmonary obstruction score, short axis diameter of right ventricle and diameter of inferior vena cava. The calculated model is characterized by 79% sensitivity and 81% specificity, and its performance was significantly better than single CT-based measurements.

Conclusion

Logistic regression model identifies RVD significantly better, than single CT-based measurements.     

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.     

Increased prevalence of coronary artery calcification in patients with suspected pulmonary embolism

RATIONALE AND OBJECTIVES: The authors explored the possibility that patients with suspected pulmonary embolism are at high risk for coronary artery disease. To this purpose, they compared the presence of coronary artery calcification on computed tomography (CT) in patients suspected of pulmonary embolism with age- and gender-matched controls. MATERIALS AND METHODS: The CT scans of 214 patients were reviewed. Of those, 107 consecutive patients (50%) had pulmonary CT angiography for suspected pulmonary embolism (PE group). The remaining 107 age- and gender-matched patients were scanned for reasons other than pulmonary embolism (non-PE group). All CT scans were performed with the same 8-detector-row multislice scanner. Two radiologists reviewed scans of 5-mm slices using a five-grade modified coronary calcium scoring system: 1 = no calcification; 2 = minimal calcification; 3 = mild calcification; 4 = moderate calcification; and 5 = severe calcification. The Marginal Homogeneity test was used to compare the distribution and severity of calcification in the two groups. RESULTS: Of 107 patients in the PE group, seven (6.54%) had pulmonary embolism detected on CT. Coronary artery calcification was detected in 61 patients (57%) in the PE group compared with 42 patients (39%) in the non-PE group. The Marginal Homogeneity test showed that patients with pulmonary embolism symptoms were 2.9 times more likely to have calcification detected compared with those patients who had chest CT for some other reason (P = .0034). However, in patients in whom coronary artery calcification was detected, the distribution of severity of calcification was the same in both groups. CONCLUSION: Assuming coronary artery calcification indicated coronary atherosclerosis, patients undergoing CT for suspected pulmonary embolism may be at high risk for coronary artery disease.     

Severity assessment of acute pulmonary embolism: role of CT angiography

Helical CT has gained wide acceptance in the noninvasive diagnosis of acute pulmonary embolism (APE) and has therefore largely replaced conventional pulmonary angiography as well as ventilation perfusion scan in the work-up of patients suspected of nonsevere pulmonary embolism (PE). Massive PE is life-threatening; its occurrence may require aggressive treatment such as thrombolysis or embolectomy. Identification of patients suffering from major thromboembolic events based solely on clinical grounds may, however, be difficult. Acute right heart failure is the principal cause of circulatory collapse and death for patients with massive PE, and rapid and specific diagnosis and therapy are required in such patients. Bedside echocardiography, a commonly performed first-line examination, demonstrates signs of cor pulmonale, if present, and can identify large central thrombi. However, echocardiography has limitations. In this review, our goal is to discuss the potential role of CT in assessing patients with severe APE. CT evaluation is based on the direct quantification of pulmonary arterial bed obstruction using various scores and the evaluation of morphological heart changes indicating acute cor pulmonale.     

The use of axial diameters and CT obstruction scores for determining echocardiographic right ventricular dysfunction in patients with acute pulmonary embolism

Purpose

To evaluate the accuracy of cardiac computed tomography (CT) parameters and pulmonary artery (PA) obstruction (OS) scores in determining the echocardiographic right ventricular dysfunction (RVD) in hemodynamically stable patients with acute pulmonary embolism (PE).

Materials and methods

A total of 120 patients with acute PE were included in the study. Right ventricle/left ventricle ratio (RV/LV); PA axial diameter; superior vena cava (SVC) axial diameter; and Ghanima, Miller, Qanadli, and Mastora obstruction scores were obtained using CT. RVD was assessed by echocardiography. The patients were divided into two groups based on the presence or absence of RVD.

Results

RV/LV ratio, SVC axial diameter, PA axial diameter, and Miller, Qanadli, and Mastora scores were significantly increased in the RVD group. Multivariate logistic regression analysis showed that RV/LV ratio [OR 6.36 (2.02–279.46 95 % CI), p = 0.01] and PA axial diameter [OR 5.02 (1.02–1.26 95 % CI), p = 0.03] were independent predictors of echocardiographic RVD. Predictive values of these parameters were improved when combined with other intragroup cutoff values. A cutoff value for the RV/LV ratio of >1.08 had 81.43 % sensitivity, 52.08 % specificity, 71.3 PPV, and 65.8 NPV for prediction of RVD.

Conclusion

Tomographic axial diameters enable more accurate predictions of RVD than OS scores do.     

Right ventricular dysfunction and pulmonary obstruction index at helical CT: prediction of clinical outcome during 3-month follow-up in patients with acute pulmonary embolism

PURPOSE: To retrospectively quantify right ventricular dysfunction (RVD) and the pulmonary artery obstruction index at helical computed tomography (CT) on the basis of various criteria proposed in the literature and to assess the predictive value of these CT parameters for mortality within 3 months after the initial diagnosis of pulmonary embolism (PE). MATERIALS AND METHODS: Institutional review board approval was obtained, and informed consent was not required for retrospective study. In 120 consecutive patients (55 men, 65 women; mean age +/- standard deviation, 59 years +/- 18) with proved PE, two readers assessed the extent of RVD by quantifying the ratio of the right ventricle to left ventricle short-axis diameters (RV/LV) and the pulmonary artery to ascending aorta diameters, the shape of the interventricular septum, and the extent of obstruction to the pulmonary artery circulation on helical CT images, which were blinded for clinical outcome in consensus reading. Regression analysis was used to correlate these parameters with patient outcome. RESULTS: CT signs of RVD (RV/LV ratio, >1.0) were seen in 69 patients (57.5%). During follow-up, seven patients died of PE. Both the RV/LV ratio and the obstruction index were shown to be significant risk factors for mortality within 3 months (P = .04 and .01, respectively). No such relationship was found for the ratio of the pulmonary artery to ascending aorta diameters (P = .66) or for the shape of the interventricular septum (P = .20). The positive predictive value for PE-related mortality with an RV/LV ratio greater than 1.0 was 10.1% (95% confidence interval [CI]: 2.9%, 17.4%). The negative predictive value for an uneventful outcome with an RV/LV ratio of 1.0 or less was 100% (95% CI: 94.3%, 100%). There was a 11.2-fold increased risk of dying of PE for patients with an obstruction index of 40% or higher (95% CI: 1.3, 93.6). CONCLUSION: Markers of RVD and pulmonary vascular obstruction, assessed with helical CT at baseline, help predict mortality during follow-up.     

Benefit of combining quantitative cardiac CT parameters with troponin I for predicting right ventricular dysfunction and adverse clinical events in patients with acute pulmonary embolism

Objective

To prospectively evaluate the diagnostic accuracy of quantitative cardiac CT parameters alone and in combination with troponin I for the assessment of right ventricular dysfunction (RVD) and adverse clinical events in patients with acute pulmonary embolism (PE).

Materials and results

This prospective study had institutional review board approval and was HIPAA compliant. In total 83 patients with confirmed PE underwent echocardiography and troponin I serum level measurements within 24 h. Three established cardiac CT measurements for the assessment of RVD were obtained (RV/LV_axial, RV/LV_4-CH, and RV/LV_volume). CT measurements and troponin I serum levels were correlated with RVD found on echocardiography and adverse clinical events according to Management Strategies and Prognosis in Pulmonary Embolism Trial-3 (MAPPET-3 criteria. 31 of 83 patients with PE had RVD on echocardiography and 39 of 83 patients had adverse clinical events. A RV/LV_volume ratio > 1.43 showed the highest area under the curve (AUC) (0.65) for the prediction of adverse clinical events when compared to RV/LV_axial, RV/LV_4Ch and troponin I. The AUC for the detection of RVD of RV/LV_axial, RV/LV_4Ch, RV/LV_volume, and troponin I were 0.86, 0.86, 0.92, and 0.69, respectively. Combination of RV/LV_axial, RV/LV_4Ch, RV/LV_volume with troponin I increased the AUC to 0.87, 0.87 and 0.93, respectively.

Conclusion

A combination of cardiac CT parameters and troponin I measurements improves the diagnostic accuracy for detecting RVD and predicting adverse clinical events if compared to either test alone.     

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.     

Air trapping on CT of patients with pulmonary embolism

OBJECTIVE: We evaluated the relationship of air trapping to mosaic perfusion in patients with pulmonary embolism. SUBJECTS AND METHODS: Forty-one consecutive patients with suspected pulmonary embolism underwent expiratory CT followed by helical CT angiography. After excluding 12 patients who had airway disease or were smokers, we divided the patients into two groups: those with (n = 15) and without (n = 14) pulmonary embolism. For each patient, six expiratory images were evaluated for the presence of air trapping, and the corresponding six images from CT angiography were evaluated for the presence of mosaic perfusion. Clot locations were assessed on CT angiography and were correlated with the presence of air trapping and mosaic perfusion. RESULTS: In patients with pulmonary embolism, mosaic perfusion was identified in 32 areas (seven patients, 46.7%), and air trapping was identified 68 areas (nine patients, 60%). Of the 32 areas of mosaic perfusion, 23 areas (71.9%) showed air trapping on expiratory CT scans. Of the 68 areas with air trapping on expiratory scans, 23 areas (33.8%) showed mosaic perfusion on inspiratory scans, and 44 areas (64.7%) had clots in the arteries leading to them. Clots were more frequently identified in areas of lower attenuation on inspiratory CT scans and air trapping (21/23) than in those of normal attenuation on inspiratory CT scans and air trapping (23/45) (p < 0.005). Only one patient without pulmonary embolism had air trapping (p < 0.005). CONCLUSION: Air trapping is common in pulmonary embolism and may be the cause of mosaic perfusion. Air trapping can be seen distal to vessels not showing pulmonary embolism.     

Widening of coronary sinus in CT pulmonary angiography indicates right ventricular dysfunction in patients with acute pulmonary embolism

Objectives  

Right ventricular dysfunction (RVD) may occur in the course of acute pulmonary embolism (PE). Patients with RVD need more intensive treatment, and the prognosis is more severe. The aim of this study was to evaluate the usefulness of the measurement of the coronary sinus in the assessment of RVD in patients with acute PE and to compare it with other indicators of RVD.     

The role of spiral CT using the pulmonary embolus protocol: a comparison of emergency department and hospitalized populations

Purpose: To compare the incidence of CT scan-detected pulmonary embolism, the CT scan-detected alternative findings (ancillary findings and alternative radiologic diagnoses), and the patient characteristics in emergency department and in hospitalized patients. Materials and methods: 81 spiral CT scans in 79 consecutive adult emergency department patients were retrospectively identified by computer search. During the same 9-month interval, 131 consecutive adult in-patients were similarly identified. The in-house and emergency department populations were compared in respect of incidence of pulmonary embolism and alternative findings using χ ² analysis. Results: 81 emergency department scans and 135 in-patient scans were evaluated. Of these, 22 emergency department scans (27.1 %) and 37 in-patient scans (27.4 %) were positive for pulmonary embolism. Of the scans that were negative for a pulmonary embolism, 45 emergency department scans (76.2 %) and 88 in-patient scans (89.8 %) were positive for alternative findings. These included atelectasis, adenopathy, metastatic disease, and pneumomediastinum. Alternative radiologic diagnoses on scans negative for pulmonary embolism occurred in 8/59 emergency department patients (13.5 %) and in 17/98 in-patients (17.3 %). These included pneumonia, tumor, mucus plugging, pericardial effusions, and thoracic aortic dissection. Conclusions: No significant difference exists between the emergency department and in-patient populations for the incidence of pulmonary embolism on spiral CT scans. Although a significant difference did exist between these populations in respect to alternative findings, the high percentage of alternative findings in both populations shows a possible advantage of CT over the traditional test, the ventilation-perfusion scan. Therefore, spiral CT should not be limited to the in-patient population as the first-line imaging modality for the diagnostic evaluation of pulmonary embolism.