Radiomics parameters of epicardial adipose tissue predict mortality in acute pulmonary embolism

BACKGROUND

Accurate prediction of short-term mortality in acute pulmonary embolism (APE) is very important. The aim of the present study was to analyze the prognostic role of radiomics values of epicardial adipose tissue (EAT) in APE.

METHODS

Overall, 508 patients were included into the study, 209 female (42.1%), mean age, 64.7 ± 14.8 years. 4.6%and 12.4% died (7- and 30-day mortality, respectively). For external validation, a cohort of 186 patients was further analysed. 20.2% and 27.7% died (7- and 30-day mortality, respectively). CTPA was performed at admission for every patient before any previous treatment on multi-slice CT scanners. A trained radiologist, blinded to patient outcomes, semiautomatically segmented the EAT on a dedicated workstation using ImageJ software. Extraction of radiomic features was applied using the pyradiomics library. After correction for correlation among features and feature cleansing by random forest and feature ranking, we implemented feature signatures using 247 features of each patient. In total, 26 feature combinations with different feature class combinations were identified. Patients were randomly assigned to a training and a validation cohort with a ratio of 7:3. We characterized two models (30-day and 7-day mortality). The models incorporate a combination of 13 features of seven different image feature classes.

FINDINGS

We fitted the characterized models to a validation cohort (n = 169) in order to test accuracy of our models. We observed an AUC of 0.776 (CI 0.671-0.881) and an AUC of 0.724 (CI 0.628-0.820) for the prediction of 30-day mortality and 7-day mortality, respectively. The overall percentage of correct prediction in this regard was 88% and 79% in the validation cohorts. Lastly, the AUC in an independent external validation cohort was 0.721 (CI 0.633-0.808) and 0.750 (CI 0.657-0.842), respectively.

INTERPRETATION

Radiomics parameters of EAT are strongly associated with mortality in patients with APE.

CLINICAL TRIAL NUMBER

Not applicable.

Pulmonary artery diameter correlates with echocardiographic parameters of right ventricular dysfunction in patients with acute pulmonary embolism

Introduction

Right ventricular dysfunction (RVD) is a key component in the process of risk stratification in patients with acute pulmonary embolism (PE). Echocardiography remains the gold standard for RVD assessment, however, measures of RVD may be seen on CTPA imaging, including increased pulmonary artery diameter (PAD). The aim of our study was to evaluate the association between PAD and echocardiographic parameters of RVD in patients with acute PE.

Methods

Retrospective analysis of patients diagnosed with acute PE was conducted at large academic center with an established pulmonary embolism response team (PERT). Patients with available clinical, imaging, and echocardiographic data were included. PAD was compared to echocardiographic markers of RVD. Statistical analysis was performed using the Student's t test, Chi-square test, or one-way analysis of variance (ANOVA); P < 0.05 was considered statistically significant.

Results

270 patients with acute PE were identified. Patients with a PAD >30 mm measured on CTPA had higher rates of RV dilation (73.1% vs 48.7%, P < 0.005), RV systolic dysfunction (65.4% vs 43.7%, P < 0.005), and RVSP >30 mmHg (90.2% vs 68%, P = 0.004), but not TAPSE ≤1.6 cm (39.1% vs 26.1%, P = 0.086). A weak increasing linear relationship between PAD and RVSP was noted (r = 0.379, P = 0.001).

Conclusions

Increased PAD in patients with acute PE was significantly associated with echocardiographic markers of RVD. Increased PAD on CTPA in acute PE can serve as a rapid prognostic tool and assist with PE risk stratification at the time of diagnosis, allowing rapid mobilization of a PERT team and appropriate resource utilization.

Computed tomographic pulmonary angiography: Three cases of low-tube-voltage acquisition with a slow injection of contrast medium

Acute pulmonary thromboembolism occurring during cancer treatment has been increasing with the number of cancer patients and chemotherapy cases. Computed tomographic pulmonary angiography (CTPA) for evaluating the pulmonary artery is generally performed using rapid injection of contrast medium. However, intravenous catheters for contrast medium injection might cause extravasation due to rapid injection. This case series describes three patients who underwent contrast-enhanced computed tomography combined with low-tube-voltage imaging and slow injection. Low-tube-voltage slow-injection CTPA can be an effective technique for obtaining high contrast enhancement while accommodating fragile veins and low injection rates.

Acute Pulmonary Embolism: Prognostic Role of Computed Tomography Pulmonary Angiography (CTPA)

Computed Tomography Pulmonary Angiography (CTPA) is considered the gold standard diagnostic technique in patients with suspected acute pulmonary embolism in emergency departments. Several studies have been conducted on the predictive value of CTPA on the outcomes of pulmonary embolism (PE). The purpose of this article is to provide an updated review of the literature reporting imaging parameters and quantitative CT scores to predict the severity of PE.

Detection of right ventricular dysfunction in acute pulmonary embolism by computed tomography or echocardiography: A systematic review and meta-analysis

BACKGROUND

Right ventricular (RV) dysfunction predicts worse outcomes in acute pulmonary embolism (PE). Because computed tomography (CT) pulmonary angiography visualizes cardiac structures, it is a potential method for assessing RV function without the delays associated with inpatient echocardiography.

OBJECTIVES

We conducted a systematic review and meta-analysis to assess the diagnostic accuracy of CT scan findings for detecting RV dysfunction compared with echocardiography.

METHODS

We searched MEDLINE and EMBASE from inception to April 2020 for studies comparing RV dysfunction on CT scan with echocardiography standard. Study quality was assessed with the QUADAS-2 risk of bias tool. Meta-analysis was performed using a bivariate mixed effects regression framework.

RESULTS

After screening, 26 studies (3508 patients) were included. In a pooled analysis, septal deviation (5 studies; 459 patients) had a sensitivity of 0.31 (95% CI 0.25-0.38; I2  = 0%), specificity of 0.98 (95% CI 0.90-1.00; I2  = 59.4%), and positive likelihood ratio of 13.6 (95% CI 3.1-60.4) for RV dysfunction compared with echocardiography. The pooled sensitivity of increased RV/left ventricular ratio (21 studies; 3111 patients) was 0.83 (95% CI 0.78-0.87; I2  = 81.8%), whereas the pooled specificity was 0.75 (95% CI 0.66-0.82; I2  = 94.2%) and negative likelihood ratio was 0.23 (0.18-0.29).

CONCLUSIONS

Overall, RV dysfunction can be detected by CT imaging but the diagnostic accuracy when compared with echocardiography varies depending on specific findings. The presence of septal bowing appears to be highly specific for RV dysfunction. Our findings suggest that multiple CT findings of RV dysfunction may improve diagnostic accuracy and further studies are warranted.

A New Index for the Prediction of 30-Day Mortality in Patients With Pulmonary Embolism: The Pulmonary Embolism Mortality Score (PEMS)

Our aim was to analyze possibility of combination of basic clinical and radiological signs to predict 30-day mortality after acute pulmonary embolism (PE). We included 486 patients. Age, gender, simplified pulmonary embolism index (sPESI), pH, troponin, N-terminal natriuretic peptide, minimal systolic and diastolic blood pressure, O2 saturation, syncope, need for vasopressors, thrombotic obstruction, vessel diameter, short axis ratio right ventricle/left ventricle, and contrast medium reflux into the inferior vena cava (IVC) were analyzed. A backward algorithm in a logistic regression model was used to identify relevant risk factors. Multiple logistic regression analysis identified that sPESI, pH, minimal diastolic blood pressure, IVC reflux, and need for vasopressors influenced 30-day mortality. A score for mortality prediction was constructed (the Pulmonary Embolism Mortality Score): sPESI >2 points (1 point), pH <7.35 (1 point), minimal diastolic blood pressure <45 mm Hg (1 point), IVC reflux (1 point), and need for vasopressors (2 points). Patients with >3 points showed higher 30-day mortality (sensitivity: 84.9%, specificity: 83.0%, positive predictive value: 51.8%, negative predictive value: 96.2%). The net reclassification improvement compared with the sPESI was 0.94 (95% CI = 0.73-1.15). In conclusion, a new score can predict 30-day mortality in patients with PE and is more sensitive than sPESI.

Contrast reflux into the inferior vena cava on computer tomographic pulmonary angiography is a predictor of 24-hour and 30-day mortality in patients with acute pulmonary embolism

BACKGROUND

Acute pulmonary embolism (PE) is a common disease with a high mortality. Computed tomographic pulmonary angiography (CTPA) represents the current gold standard for the evaluation of patients with suspected PE.

PURPOSE

To search possible CTPA predictors of 24-h and 30-day mortality in PE.

MATERIAL AND METHODS

Overall, 224 patients with PE (46.4% women, mean age 64.7 ± 16.7 years) were acquired. CTPA was performed on a multi-slice CT scanner. The following radiological parameters were estimated: thrombotic obstruction index; diameter of the pulmonary trunk (mm); short axis ratio of right ventricle/left ventricle; diameter of the azygos vein (mm); diameter of the superior and inferior vena cava (mm); and reflux of contrast medium into the inferior vena cava (IVC).

RESULTS

Patients who died within the first 24 h after admission (n = 32, 14.3%) showed a reflux grade 3 into IVC more often than survivors (odds ratio [OR] 7.6, 95% confidence interval [CI] 3.3-17.7; P < 0.001). Other relevant CTPA parameters were diameter of IVC (OR 1.1, 95% CI 1.01-1.21; P = 0.034) and diameter of the pulmonary trunk (OR 0.91, 95% CI 0.82-1.01, P = 0.074), whereas the Mastora score showed nearly no influence (OR 1.01, 95% CI 0.99-1.02, P = 0.406). Furthermore, 61 (27.2%) patients died within the first 30 days after admission. These patients showed a reflux grade 3 into IVC more often than survivors (OR 3.4, 95% CI 1.7-7.0; P = 0.001). Other CTPA parameters, such as diameter of IVC (OR 1.04, 95% CI 0.97-1.12; P = 0.277) and diameter of the pulmonary trunk (OR 0.96, 95% CI 0.89-1.04; P = 0.291), seem to have no relevant influence, whereas Mastora score did (OR 0.99, 95% CI 0.976-0.999, P = 0.045).

CONCLUSION

Subhepatic contrast reflux into IVC is a strong predictor of 24-h and 30-day mortality in patients with acute PE.

Visual Estimation of Tricuspid Annular Plane Systolic Excursion by Emergency Medicine Clinicians

INTRODUCTION

Tricuspid annular plane systolic excursion (TAPSE) is an established echocardiographic marker of right ventricular (RV) systolic function. The objective of this study was to evaluate whether emergency clinicians can visually estimate RV function using TAPSE in a set of video clips compared to a reference standard M-mode measurement.

METHODS

Emergency clinicians were shown a five-minute educational video on TAPSE. Participants then viewed 20 apical four-chamber point-of-care ultrasound (POCUS) echocardiography clips and recorded their estimate of TAPSE distance in centimeters (cm), as well as whether TAPSE was normal (>1.9 cm), borderline (1.5-1.9 cm), or abnormal (<1.5 cm). We calculated sensitivity, specificity, and overall accuracy of visual TAPSE categorization using M-mode measurement as the criterion standard. Participants also reported their comfort with assessing TAPSE on a five-point Likert scale before and after participation in the study.

RESULTS

Among 70 emergency clinicians, including 20 postgraduate year 1-4 residents, 22 attending physicians, and 28 physician assistants (PA), the pooled sensitivity and specificity for visual assessment of TAPSE was 88.6% (95% confidence interval, 85.4-91.7%) and 81.6% (95% CI, 78.2-84.4%), respectively. The sensitivity and specificity for the clips in which the measured TAPSE was <1.5 cm or >1.9 cm was 91.4% (95% CI, 88.4-94.3%) and 90.8% (95% CI, 87.7-93.9%), respectively. There was no significant difference in sensitivity (p = 0.27) or specificity (p = 0.55) between resident and attending physicians or between physicians and PAs (p = 0.17 and p = 0.81). Median self-reported comfort with TAPSE assessment increased from 1 (interquartile range [IQR] 1-2) to 3 (IQR 3-4) points after participation in the study.

CONCLUSION

A wide range of emergency clinicians demonstrated fair accuracy for visual estimation of TAPSE on previously recorded POCUS echocardiography video clips. These findings should be considered hypothesis generating and warrant validation in larger, prospective studies.

A Novel Predictive Method Incorporating Parameters of Main Pulmonary Artery Bifurcation for Short-Term Prognosis in Non-high-risk Acute Pulmonary Embolism Patients

The aim of this study was to build a formula to predict short-term prognosis using main pulmonary artery (MPA) parameters reconstructed from computed tomographic pulmonary angiography in non-high-risk acute pulmonary embolism (PE) patients. After reconstructing the MPA and its centerline, the MPA, the right and left pulmonary artery inlet, and the MPA outlet plane were differentiated to measure the cross-sectional area (CSA), the maximal diameter and the hydraulic diameter. The MPA bifurcation area, volume and angle were measured. MPA dilation was defined as >29 mm at the transverse section plane. The patients were randomly divided into a training set and a validation set. A least absolute shrinkage and selection operator (LASSO) logistic regression algorithm was used to build a predictive formula. The performances of the predictive formula from LASSO were tested by the area under the receiver operating characteristic curve (AUC) and precision-recall (PR) curve with 10-fold cross-validation. The clinical utility was assessed by decision curve analysis (DCA). In total, 296 patients were enrolled and randomly divided (50:50) into a training set and a validation set. The LASSO predictive formula (lambda.1SE) was as follows: 0.92 × MPA bifurcation area + 0.50 × MPA outlet hydraulic diameter + 0.10 × MPA outlet CSA. The AUCs of the predictive formula were 0.860 (95% CI: 0.795-0.912) and 0.943 (95% CI: 0.892-0.975) in the training set and validation set, respectively. The LASSO predictive formula had a higher average area under the PR curve than MPA dilation (0.71 vs. 0.23 in the training set and 0.55 vs. 0.23 in the validation set) and added a net benefit in clinical utility by DCA. Integration of MPA outlet CSA, hydraulic diameter, and bifurcation area with the LASSO predictive formula as a novel weighting method facilitated the prediction of poor short-term prognosis within 30 days after hospital admission in non-high-risk acute PE patients.

Multimodality cardiovascular imaging in pulmonary embolism

Acute pulmonary embolism (APE) is one of the leading causes of cardiovascular (CV) morbidity and mortality. To select appropriate therapeutic strategy and/or to minimize the mortality and morbidity, rapid and correct identification of life-threatening APE is very important. Also, right ventricular (RV) failure usually precedes acute hemodynamic compromise or death, and thus the identification of RV failure is another important step in risk stratification or treatment of APE. With advances in diagnosis and treatment, the prognosis of APE has been dramatically improving in most cases, but inadequate therapy or recurrent episodes of pulmonary embolism (PE) may result in negative outcomes or, so called, chronic thromboembolic pulmonary hypertension (CTEPH). CTEPH is a condition characterized by remaining chronic thromboembolic material in the pulmonary vasculature and subsequent chronic pulmonary hypertension. Various imaging modalities include chest computed tomography pulmonary angiography (CTPA), echocardiography, magnetic resonance imaging, and nuclear imaging and each are used for the assessment of varying status of PE. Assessment of thromboembolic burden by chest CTPA is the first step in the diagnosis of PE. Hemodynamic assessment can be achieved by echocardiography and also by chest CTPA. Nuclear imaging is useful in discriminating CTEPH from APE. Better perspectives on diagnosis, risk stratification and decision making in PE can be provided by combining multimodality CV imaging. Here, the advantages or pitfalls of each imaging modality in diagnosis, risk stratification, or management of PE will be discussed.

Prognostic value of cardiovascular parameters in computed tomography pulmonary angiography in patients with acute pulmonary embolism

The value of various computed tomography parameters for prognosis and risk stratification in acute pulmonary embolism is controversial. Our objective was to evaluate the impact of specific cardiovascular computed tomography pulmonary angiography parameters on short- and long-term clinical outcomes.

We analysed radiological and clinical data of 1950 patients with acute pulmonary embolism who participated in an international randomised clinical trial on anticoagulants. Parameters included right/left ventricular ratio, septal bowing, cardiothoracic ratio, diameters of pulmonary trunk and aorta, and intrahepatic/azygos vein contrast medium backflow. Associations with mortality, recurrent venous thromboembolism (VTE), hospitalisation, bleeding and adverse events were assessed over the short term (1 week and 1 month) and long term (12 months).

Pulmonary trunk enlargement was the only parameter significantly associated with mortality over both the short and long term (OR 4.18 (95% CI 1.04–16.76) at 1 week to OR 2.33 (95% CI 1.36–3.97) after 1 year), as well as with recurrent VTE and hospitalisation.

Most of the evaluated radiological parameters do not have strong effects on the short- or long-term outcome in patients with acute pulmonary embolism. Only an enlarged pulmonary trunk diameter carries an increased risk of mortality and recurrent VTE up to 12 months, and can be used for risk stratification.

Contrast Circulation Time to Assess Right Ventricular Dysfunction in Pulmonary Embolism: A Retrospective Pilot Study

Objective

To optimize enhancement of pulmonary arteries and facilitate diagnosis of pulmonary embolism (PE), modern computed tomography angiography (CTA) contains a contrast bolus tracking system. We explored the diagnostic accuracy of the time-intensity curves given by this automated system to identify right ventricular dysfunction (RVD) in acute PE.

Methods

114 CTAs with a diagnosis of PE were reviewed. RVD was defined as right-to-left ventricular diameter ratio of 1 or greater. Four parameters on time-intensity curves were identified. Parameters between CTAs with and those without RVD were compared with the Wilcoxon rank-sum test. The ability of the four parameters to discriminate patients with RVD was explored by compiling the area under the operating curves (AUC).

Results

The time needed by the contrast media to reach the pulmonary artery [8 seconds (IQR: 7–9) versus 7 seconds (IQR: 6–8), p<0.01], the time needed to reach 40 Hounsfield units (HU) [11 seconds (IQR: 8.5–14) versus 9.5 seconds (IQR: 8–10.5), p<0.01], and the contrast intensity reached after 10 seconds [19 HU (IQR: 4–67) versus 53 HU (IQR: 32–80), p<0.05] were all statistically different between CTA with and CTA without RVD. Those three parameters changed gradually across severity categories of RVD (p<0.05 for trend). Their AUC to identify RVD ranged from 0.63 to 0.66. The slope of contrast intensity over time was not informative: [31 HU/s (IQR: 20–57) in CTA with, compared to 36 HU/s (IQR: 22.5–53) in CTA without RVD, p = 0.60].

Conclusion

Several parameters of the time-intensity curve obtained by the bolus tracking system are associated with RVD assessed on CTA images. Of those, the time needed to reach a predefined threshold seems to be the easiest to obtain in any CTA without additional processing time or contrast injection. However, the performance of those parameters is globally low.

Predictive Value of Computed Tomography in Acute Pulmonary Embolism: Systematic Review and Meta-analysis

BACKGROUND

Many computed tomography (CT) parameters have been proposed as potential predictors of outcome in acute pulmonary embolism. We sought to summarize available evidence on the predictive value of CT severity parameters for short-term clinical outcome in pulmonary embolism.

METHODS

We searched PubMed and EMBASE through February 2014 for studies that reported on the association between CT parameters of acute pulmonary embolism severity and short-term (≤6 months) clinical outcome. Risk estimates for quantitative parameters of right ventricular (RV) dysfunction (abnormally increased RV/left ventricular [LV] diameter ratio on transverse sections and 4-chamber views), qualitative parameters of RV dysfunction (abnormal septal morphology and contrast reflux), thrombus load, and central thrombus location were derived using random effect regression analysis. Meta-regression analysis was performed to quantify and explain study heterogeneity.

RESULTS

A total of 49 studies with 13,162 patients with acute pulmonary embolism (median age of 61 years, 55.1% were women) who underwent diagnostic CT imaging were included in the analysis. An abnormally increased RV/LV diameter ratio measured on transverse sections was associated with an approximately 2.5-fold risk for all-cause mortality (pooled odds ratio [OR], 2.5; 95% confidence interval [CI], 1.8-3.5) and adverse outcome (OR, 2.3; 95% CI, 1.6-3.4) and a 5-fold risk for pulmonary embolism-related mortality (OR, 5.0; 95% CI, 2.7-9.2). Thrombus load (OR, 1.6, 95% CI, 0.7-3.9; P = .2896) and central location (OR, 1.7; 95% CI, 0.7-4.2; P = .2609) were not predictive for all-cause mortality, although both were associated with adverse clinical outcome.

CONCLUSIONS

Across all end points, the RV/LV diameter ratio on transverse CT sections has the strongest predictive value and most robust evidence base for adverse clinical outcomes in patients with acute pulmonary embolism.

Hemodynamic indexes derived from computed tomography angiography to predict pulmonary embolism related mortality

Pulmonary embolism (PE) induces an acute increase in the right ventricle afterload that can lead to right-ventricular dysfunction (RVD) and eventually to circulatory collapse. Hemodynamic status and presence of RVD are important determinants of adverse outcomes in acute PE. Technologic progress allows computed tomography angiography (CTA) to give more information than accurate diagnosis of PE. It may also provide an insight into hemodynamics and right-ventricular function. Proximal localization of emboli, reflux of contrast medium to the hepatic veins, and right-to-left short-axis ventricular diameter ratio seem to be the most relevant CTA predictors of 30-day mortality. These elements require little postprocessing time, an advantage in the emergency room. We herein review the prognostic value of RVD and other CTA mortality predictors for patients with acute PE.

Imaging of acute pulmonary embolism

Acute pulmonary thromboembolism (PE) is a cardiovascular emergency associated with significant morbidity and a 5-35 % mortality for untreated pulmonary embolism. If promptly diagnosed and treated, the mortality rate can be significantly reduced. Diagnosis of acute PE continues to be a clinical challenge, with diagnostic imaging playing an important role. This review discusses the clinical challenges of diagnosing acute PE, presents an evidence-based review of the current tests and ever-evolving imaging technology, and highlights special considerations related to radiation dose, contrast media use, and pregnant patients.