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

Accuracy of transthoracic lung ultrasound for diagnosing pulmonary embolism: An updated systematic review and meta-analysis

BACKGROUND

Computed tomography pulmonary angiography (CTPA) simplifies the diagnosis of pulmonary embolism (PE) but is not suitable for all patients. Transthoracic lung ultrasound (LUS) is a potential alternative; this meta-analysis evaluates its accuracy for diagnosing PE.

METHODS

We systematically searched PubMed, Embase and Cochrane Library from the inception of each database up to April 2024 according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses of Diagnostic Test Accuracy Studies guidelines. Study quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 tool, and a bivariate random effects model was used to pool sensitivity and specificity.

RESULTS

A total of 18 studies with 2158 patients were analyzed. Lung ultrasound showed a sensitivity of 0.80 (95 %, confidence interval (CI): 0.71-0.86; I2 = 85.2 %) and specificity of 0.87 (95 %, CI: 0.81-0.92; I2 = 87.3 %). The diagnostic score was 3.27 (95 %, CI: 2.75-3.78; I2 = 61.9 %), and the diagnostic odds ratio was 26 (95 %, CI: 16-44; I2 = 100.0 %). The pooled positive likelihood ratio was 6.2 (95 %, CI: 4.2-9.1; I2 = 79.2 %), and the negative likelihood ratio was 0.24 (95 %, CI: 0.16-0.34; I2 = 83.7 %). The summary area under the curve was 0.91 (95 %, CI: 0.88-0.93). Significant heterogeneity was observed, which may impact the generalisability of the results, and no publication bias was detected.

CONCLUSION

Transthoracic LUS shows potential as an alternative to CTPA for PE diagnosis, but further research is needed to improve its accuracy and establish standardised diagnostic criteria. The observed heterogeneity highlights the need for a cautious interpretation of the results.

nnU-Net-based deep-learning for pulmonary embolism: detection, clot volume quantification, and severity correlation in the RSPECT dataset

OBJECTIVES

CT pulmonary angiography is the gold standard for diagnosing pulmonary embolism, and DL algorithms are being developed to manage the increase in demand. The nnU-Net is a new auto-adaptive DL framework that minimizes manual tuning, making it easier to develop effective algorithms for medical imaging even without specific expertise. This study assesses the performance of a locally developed nnU-Net algorithm on the RSPECT dataset for PE detection, clot volume measurement, and correlation with right ventricle overload.

MATERIALS & METHODS

User input was limited to segmentation using 3DSlicer. We worked with the RSPECT dataset and trained an algorithm from 205 PE and 340 negatives. The test dataset comprised 6573 exams. Performance was tested against PE characteristics, such as central, non-central, and RV overload. Blood clot volume (BCV) was extracted from each exam. We employed ROC curves and logistic regression for statistical validation.

RESULTS

Negative studies had a median BCV of 1 μL, which increased to 345 μL in PE-positive cases and 7,378 μL in central PEs. Statistical analysis confirmed a significant BCV correlation with PE presence, central PE, and increased RV/LV ratio (p < 0.0001). The model's AUC for PE detection was 0.865, with an 83 % accuracy at a 55 μL threshold. Central PE detection AUC was 0.937 with 91 % accuracy at 850 μL. The RV overload AUC stood at 0.848 with 79 % accuracy.

CONCLUSION

The nnU-Net algorithm demonstrated accurate PE detection, particularly for central PE. BCV is an accurate metric for automated severity stratification and case prioritization.

CLINICAL RELEVANCE STATEMENT

The nnU-Net framework can be utilized to create a dependable DL for detecting PE. It offers a user-friendly approach to those lacking expertise in AI and rapidly extracts the Blood Clot Volume, a metric that can evaluate the PE's severity.

Modern imaging of acute pulmonary embolism

The first-choice imaging test for visualization of thromboemboli in the pulmonary vasculature in patients with suspected acute pulmonary embolism (PE) is multidetector computed tomography pulmonary angiography (CTPA) - a readily available and widely used imaging technique. Through technological advancements over the past years, alternative imaging techniques for the diagnosis of PE have become available, whilst others are still under investigation. In particular, the evolution of artificial intelligence (AI) is expected to enable further innovation in diagnostic management of PE. In this narrative review, current CTPA techniques and the emerging technology photon-counting CT (PCCT), as well as other modern imaging techniques of acute PE are discussed, including CTPA with iodine maps based on subtraction or dual-energy acquisition, single-photon emission CT (SPECT), magnetic resonance angiography (MRA), and magnetic resonance direct thrombus imaging (MRDTI). Furthermore, potential applications of AI are discussed.

Clot ratio, new clot burden score with deep learning, correlates with the risk stratification of patients with acute pulmonary embolism

Background

Risk stratification for patients with acute pulmonary embolism (APE) is significantly important for treatment and prognosis evaluation. We aimed to develop a novel clot burden score on computed tomography pulmonary angiography (CTPA) based on deep learning (DL) algorithm for risk stratification of APE.

Methods

The study retrospectively enrolled patients newly diagnosed with APE in China-Japan Friendship Hospital consecutively. We collected baseline data and CTPA parameters, and calculated four different clot burden scores, including Qanadli score, Mastora score, clot volume and clot ratio. The former two were calculated by two radiologists separately, while clot volume and clot ratio were based on the DL algorithm. The area under the curve (AUC) of four clot burden scores were analyzed.

Results

Seventy patients were enrolled, including 17 in high-/intermediate-high risk and 53 in low-/intermediate-low risk. Clot burden was related to the risk stratification of APE. Among four clot burden scores, clot ratio had the highest AUC (0.719, 95% CI: 0.569-0.868) to predict patients with higher risk. In the patients with hemodynamically stable APE, only clot ratio presented statistical difference (P=0.046).

Conclusions

Clot ratio is a new imaging marker of clot burden which correlates with the risk stratification of patients with APE. Higher clot ratio may indicate higher risk and acute right ventricular dysfunction in patients with hemodynamically stable status.

[Research progress on electrical impedance tomography in pulmonary perfusion]

Electrical impedance tomography (EIT) is an emerging technology for real-time monitoring based on the impedance differences of different tissues and organs in the human body. It has been initially applied in clinical research as well as disease diagnosis and treatment. Lung perfusion refers to the blood flow perfusion function of lung tissue, and the occurrence and development of many diseases are closely related to lung perfusion. Therefore, real-time monitoring of lung perfusion is particularly important. The application and development of EIT further promote the monitoring of lung perfusion, and related research has made great progress. This article reviews the principles of EIT imaging, lung perfusion imaging methods, and their clinical applications in recent years, with the aim of providing assistance to clinical and scientific researchers.

A closer look at the utilized radiation doses during computed tomography pulmonary angiography (CTPA) for COVID-19 patients

Introduction

CTPA stands for computed tomography pulmonary angiography. CTPA is an X-ray imaging that combines X-rays and computer technology to create detailed images of the pulmonary arteries and veins in the lungs. This test diagnoses and monitors conditions like pulmonary embolism, arterial blockages, and hypertension. Coronavirus (COVID-19) has threatened world health over the last three years. The number of (CT) scans increased and played a vital role in diagnosing COVID-19 patients, including life-threatening pulmonary embolism (PE). This study aimed to assess the radiation dose resulted from CTPA for COVID-19 patients.

Methods

Data were collected retrospectively from CTPA examinations on a single scanner in 84 symptomatic patients. The data collected included the dose length product (DLP), volumetric computed tomography dose index (CTDIvol), and size-specific dose estimate (SSDE). The organ dose and effective dose were estimated using VirtualDose software.

Results

The study population included 84 patients, 52% male and 48% female, with an average age of 62. The average DLP, CTDIvol, and SSDE were 404.2 mGy cm, 13.5 mGy, and 11.6 mGy\, respectively. The mean effective doses (mSv) for males and females were 3.01 and 3.29, respectively. The maximum to minimum organ doses (mGy) between patients was 0.8 for the male bladder and 7.33 for the female lung.

Conclusions

The increase in CT scans during the COVID-19 pandemic required close dose monitoring and optimization. The protocol used during CTPA should guarantee a minimum radiation dose with maximum patient benefits.

Bilateral Emboli and Highest Heart Rate Predict Hospitalization of Emergency Department Patients With Acute, Low-Risk Pulmonary Embolism

STUDY OBJECTIVE

Some patients with acute pulmonary embolism (PE) will suffer adverse clinical outcomes despite being low risk by clinical decision rules. Emergency physician decisionmaking processes regarding which low-risk patients require hospitalization are unclear. Higher heart rate (HR) or embolic burden may increase short-term mortality risk, and we hypothesized that these variables would be associated with an increased likelihood of hospitalization for patients designated as low risk by the PE Severity Index.

METHODS

This was a retrospective cohort study of 461 adult emergency department (ED) patients with a PE Severity Index score of fewer than 86 points. Primary exposures were the highest observed ED HR, most proximal embolus location (proximal vs distal), and embolism laterality (bilateral vs unilateral PE). The primary outcome was hospitalization.

RESULTS

Of 461 patients meeting inclusion criteria, most (57.5%) were hospitalized, 2 patients (0.4%) died within 30 days, and 142 (30.8%) patients were at elevated risk by other criteria (Hestia criteria or biochemical/radiographic right ventricular dysfunction). Variablesassociated with an increased likelihood of admission were highest observed ED HR of ≥110 beats/minute (vs HR <90 beats/min) (adjusted odds ratio [aOR] 3.11; 95% confidence interval [CI] 1.07 to 9.57), highest ED HR 90 to 109 (aOR 2.03; 95% CI 1.18-3.50) and bilateral PE (aOR 1.92; 95% CI 1.13 to 3.27). Proximal embolus location was not associated with the likelihood of hospitalization (aOR 1.19; 95% CI 0.71 to 2.00).

CONCLUSIONS

Most patients were hospitalized, often with recognizable high-risk characteristics not accounted for by the PE Severity Index. Highest ED HR of ≥90 beats/min and bilateral PE were associated with a physician's decision for hospitalization.

Bibliometric Analysis of Diagnostic Yield of CT Pulmonary Angiogram (CTPA) in the Diagnosis of Pulmonary Embolism (PE)

CT pulmonary angiography (CTPA) is the investigation of choice for diagnosing pulmonary embolism (PE). Due to the speed and ease of performing the CTPA scans, more clinicians are becoming overly reliant on them, even for patients without strong suspicion of PE. We conducted a bibliometric analysis on the PubMed database from 1990 to 2022 to investigate the literature on the diagnostic yield of CTPA in the diagnosis of PE. A total of 166 articles were published in 98 journals. The number of publications has steadily increased since 2010 and peaked in 2020. Authors from 24 countries contributed to these publications, with the overwhelming majority emanating from United States of America, totaling 66 articles. The authors' contributions were relatively well spread out, with the top four authors publishing the highest number of articles at six each. When we investigated the collaboration between the authors, we found limited multinational and multi-institutional collaborations on this topic. Therefore, more multinational and multi-institutional collaborations will be valuable in future studies. In conclusion, this bibliometric analysis summarizes the literature on diagnostic yield of CTPA in the diagnosis of PE and sheds light on the future pathway that researchers and institutions can focus on.

Successful cardiopulmonary resuscitation of cardiac arrest induced by massive pulmonary embolism under general anesthesia: a case report

Background

While pulmonary embolism (PE) is a common occurrence, a large life-threatening PE is not. Herein, we discuss the case of a patient with a life-threatening PE that occurred under general anesthesia.

Case presentation

We present the case of a 59-year-old male patient who was at bed rest for several days due to trauma, which resulted in femoral and rib fractures and a lung contusion. The patient was scheduled for femoral fracture reduction and internal fixation under general anesthesia. After disinfection and surgical towel laying, there was a sudden occurrence of severe PE and cardiac arrest; the patient was successfully resuscitated. Computed tomography pulmonary angiography (CTPA) was performed to confirm the diagnosis, and the patient's condition improved after thrombolytic therapy. Unfortunately, the patient's family eventually discontinued treatment.

Discussion

Massive PE frequently occurs suddenly, may endanger a patient's life at any point in time, and cannot be diagnosed quickly on the basis of clinical manifestations. Although the vital signs fluctuate greatly and there is insufficient time to conduct more tests, some factors such as special disease history, electrocardiography, end-tidal carbon dioxide, and blood gas analysis may help us determine the preliminary diagnosis; however, the final diagnosis is made using CTPA. Current treatment options include thrombectomy, thrombolysis, and early anticoagulation, of which thrombolysis and early anticoagulation are the most feasible.

Conclusion

Massive PE is a life-threatening disease that requires early diagnosis and timely treatment to save patients' lives.

Imaging in Non-Traumatic Emergencies

"Emergency" is a scenario that every medical professional must face since the first day of her/his career [...].

Diagnostic Yield of CT Pulmonary Angiogram in the Diagnosis of Pulmonary Embolism and Its Predictive Factors

Introduction Computed tomography pulmonary angiography (CTPA) is the reference investigation of choice to diagnose pulmonary embolism (PE). Nevertheless, the use of CTPA should be weighed against its risks, such as radiation and contrast-induced nephropathy. We aim to assess the yield of CTPA in diagnosing PE at a tertiary centre in Malaysia. We also identify predictive factors associated with the yield of CTPA in this cohort. Methods This was a cross-sectional study involving all patients who had had CTPA done at Hospital Tengku Ampuan Afzan, Kuantan, Malaysia, from January 1, 2021, to November 30, 2021. All patients' records were retrieved and reviewed. CTPA images were retrieved from the Radiology Information System (RIS) and Picture Archiving and Communication System (PACS). They were double-reviewed by the authors, with the initial reports redacted from reporting radiologists to prevent reporting bias. The predictive factors were determined using simple logistic regression and multiple logistic regression. Results A total of 351 CTPAs were reviewed, of which 93 were found to be positive for PE, giving rise to an overall CTPA yield of 26.5%. Upon simple logistic regression, factors such as gender, discipline, history of trauma, presence of COVID-19 infection, and pneumonia were found to be associated with positive CTPA. Upon multiple logistic regression, male patients were found to have a higher chance of positive CTPA results. On the other hand, patients with COVID-19 infection and pneumonia have a lower chance of positive results in CTPA. Conclusion The yield of CTPA in diagnosing PE at our institution was acceptable at 26.5%. Upon multiple logistic regression, patients with COVID-19 infection and pneumonia were more likely to have a negative CTPA result, highlighting the need for clinicians to be more prudent in requesting CTPAs in these patients.

Comparison of echocardiographic pulmonary flow Doppler markers in patients with massive or submassive acute pulmonary embolism and control group: A cross-sectional study

Background and Aims

Computed tomography angiography (CTA) is the gold standard for the diagnosis of massive (MPE) and submassive pulmonary embolism (SMPE). Ultrasound has not been accepted as a diagnostic tool. We aim to evaluate the pattern of pulmonary Doppler echocardiography in patients with pulmonary embolism (PE).

Methods

From 2020 to 2022, 30 patients with acute MPE or SMPE confirmed by CTA and normal pulmonary pressures were selected. A control group was created with 30 individuals without PE. All patients had an echocardiography Doppler study of the pulmonary flow with a focus on early systolic notching (ESN), McConnell's (MC) sign, Right ventricular outflow tract velocity time integral (RVOT VTI), segmental thickness variability (STV), right ventricular end-diastolic diameter (RVEDD), tricuspid regurgitation (TR) gradient, pulmonary artery pressure (PAP), and acceleration (AT) or ejection time (ET).

Results

ESN was identified in 96.6% of PE patients and 0% of the control group (p < 0.001). In comparison with the control group, STV (p < 0.001), RVOT VTI (p < 0.001), ET (p = 0.04), and AT (p < 0.001) values were lower in patients with PE while RVEDD, TR gradient, PAP, ESN, MC sign, and d-shape were higher (p < 0.001). Identification of the ESN pattern and AT/ET < 0.4 showed excellent predictive ability for MPE and SMPE with a sensitivity of 97.0% and 100%, specificity of 99.0% and 97%, and an area under the ROC curve of 0.967 (95% CI 0.914-1.00) and 0.933 (95% CI 0.844-1.00), respectively.

Conclusion

Doppler echocardiography with particular attention to ESN, may be a suitable noninvasive method for the diagnosis of MPE and SMPE. Further studies with more sample sizes are needed to confirm its diagnostic benefit.

Association of Pre-Pregnancy Obesity and COVID-19 with Poor Pregnancy Outcome

BACKGROUND AND OBJECTIVES

During the COVID-19 pandemic, a possible overlap of obesity and COVID-19 infection has raised concerns among patients and healthcare professionals about protecting pregnant women from developing a severe infection and unwanted pregnancy outcomes. The aim of this study was to evaluate the associations of body mass index with clinical, laboratory, and radiology diagnostic parameters as well as pregnancy complications and maternal outcomes in pregnant patients with COVID-19.

MATERIALS AND METHODS

Clinical status, laboratory, and radiology diagnostic parameters and pregnancy outcomes were analyzed for pregnant women hospitalized between March 2020 and November 2021 in one tertiary-level university clinic in Belgrade, Serbia, due to infection with SARS-CoV-2. Pregnant women were divided into the three sub-groups according to their pre-pregnancy body mass index. For testing the differences between groups, a two-sided p-value <0.05 (the Kruskal-Wallis and ANOVA tests) was considered statistically significant.

RESULTS

Out of 192 hospitalized pregnant women, obese pregnant women had extended hospitalizations, including ICU duration, and they were more likely to develop multi-organ failure, pulmonary embolism, and drug-resistant nosocomial infection. Higher maternal mortality rates, as well as poor pregnancy outcomes, were also more likely to occur in the obese group of pregnant women. Overweight and obese pregnant women were more likely to develop gestational hypertension, and they had a higher grade of placental maturity.

CONCLUSIONS

Obese pregnant women hospitalized due to COVID-19 infection were more likely to develop severe complications.

Pulmonary thromboembolic events in COVID‐19 – a systematic literature review

Pulmonary thromboembolic events have been linked to coronavirus disease 2019 (COVID‐19), but their incidence and long‐term sequelae remain unclear. We performed a systematic literature review to investigate the incidence of pulmonary embolism (PE), microthrombi, thrombosis in situ (thromboinflammatory disease), and chronic thromboembolic pulmonary hypertension (CTEPH) during and after COVID‐19. PubMed and the World Health Organization Global Research Database were searched on May 7, 2021. Hospital cohort and database studies reporting data for ≥1000 patients and autopsy studies reporting data for ≥20 patients were included. Results were summarized descriptively. We screened 1438 records and included 41 references (32 hospital/database studies and 9 autopsy studies). The hospital/database studies reported the incidence of PE but not CTEPH, microthrombi, or thromboinflammatory disease. PE incidence varied widely (0%–1.1% of outpatients, 0.9%–8.2% of hospitalized patients, and 1.8%–18.9% of patients in intensive care). One study reported PE events occurring within 45 days after hospital discharge (incidence in discharged patients: 0.2%). Segmental arteries were generally the most common location for PE. In autopsy studies, PE, thromboinflammatory disease, and microthrombi were reported in 6%–23%, 43%–100%, and 45%–84% of deceased patients, respectively. Overall, the included studies mostly focused on PE during the acute phase of COVID‐19. The results demonstrate the challenges of identifying and characterizing vascular abnormalities using current protocols (e.g., visual computed tomography reads). Further research is needed to detect subtle pulmonary vascular abnormalities, distinguish thromboinflammatory disease from PE, optimize treatment, and assess the incidence of long‐term sequelae after COVID‐19.

Role of CT and MRI in Cardiac Emergencies

Current strategies for the evaluation of patients with chest pain have significantly changed thanks to the implemented potentiality of CT and MRI. The possible fatal consequences and high malpractice costs of missed acute coronary syndromes lead to unnecessary hospital admissions every year. CT provides consistent diagnostic support, mainly in suspected coronary disease in patients with a low or intermediate pre-test risk. Moreover, it can gain information in the case of cardiac involvement in pulmonary vascular obstructive disease. MRI, on the other hand, has a leading role in the condition of myocardial damage irrespective of the underlying inflammatory or stress related etiology. This article discusses how radiology techniques (CT and MRI) can impact the diagnostic workflow of the most common cardiac and vascular pathologies that are responsible for non-traumatic chest pain admissions to the Emergency Department.