Canadian Society of Thoracic Radiology/Canadian Association of Radiologists Best Practice Guidance for Investigation of Acute Pulmonary Embolism, Part 1: Acquisition and Safety Considerations

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.

Exploring pregnant individuals' counseling needs regarding urgent imaging to rule out pulmonary embolism

Background

Computed tomography pulmonary angiogram and lung scintigraphy with ventilation/perfusion scan are needed to diagnose pulmonary embolism (PE) in pregnancy. Their associated ionizing radiation doses are considered safe in pregnancy. A standardized patient information tool may improve patient counseling and reduce testing hesitancy.

Objectives

In this context, we sought to address 1) what patients want to know before undergoing these tests and 2) how they want the information to be provided to them.

Methods

We used a qualitative descriptive methodology. We recruited pregnant participants at the McGill University Health Center in Montreal, Canada. Structured interviews explored information needs about PE and diagnostic imaging for PE. The interview transcripts' themes were analyzed with a hybrid deductive and inductive approach.

Results

Of 21 individuals approached, 20 consented to participate. Four had been previously investigated for PE. Participants requested information about the risks associated with PE and radiation and their effects on maternal and fetal health. They preferred for radiation doses to be presented in comparison with known radiation thresholds for fetal harm. They suggested that a written tool should be developed using an accessible language. Participants also indicated that the tool would be integrated into their decision-making process, emphasizing a lower risk tolerance for their fetus than for themselves.

Conclusion

This single-center group of pregnant patients wished to be informed about the risks of PE and radiation associated with imaging. A written tool could help put information into context and facilitate decision making. These new insights may be used to inform counseling.

Venous Thromboembolism in Pregnancy: Challenges and Solutions

Venous thromboembolism (VTE) is a serious medical condition that can lead to severe morbidity and mortality, making it a significant public health concern. VTE is a multifactorial condition that results from the interaction of genetic, acquired, and environmental factors. Physiological changes during pregnancy increase the risk of VTE as they express Virchow's triad (increased coagulation factors, decreased fibrinolysis, trauma, and venous stasis). Moreover, pregnancy-related risk factors, such as advanced maternal age, obesity, multiple gestations, and cesarean delivery, further increase the risk of VTE. Managing VTE in pregnancy is challenging due to the complexity of balancing the risks and benefits of anticoagulant therapy for both the mother and the fetus. A multidisciplinary approach involving obstetricians, hematologists, and neonatologists, is necessary to ensure optimal outcomes for both the mother and baby. This review aims to discuss the current challenges associated with VTE in pregnancy and identify potential solutions for improving outcomes for pregnant women at risk for VTE.

Venous Thromboembolism During Pregnancy and the Postpartum Period: Risk Factors, Diagnostic Testing, and Treatment

Importance

The risk of venous thromboembolism (VTE) increases during pregnancy and the postpartum period. Deep vein thrombosis is the most common VTE during pregnancy, but pulmonary embolism is typically of greater concern as it contributes to far higher morbidity and mortality. Diagnosis and treatment of VTE during pregnancy differ substantially from the general nonpregnant population.

Objective

This review describes the epidemiology, risk factors, clinical presentation, diagnosis, and treatment of VTE during pregnancy and the postpartum period.

Evidence Acquisition

First, we reviewed the VTE guidelines from professional societies in obstetrics, cardiology, hematology, emergency medicine, pulmonology, and critical care. Second, we examined references from these documents and used PubMed to identify recent articles that cited the guidelines. Finally, we searched PubMed and Google Scholar for articles published since 2018 that included terms for pregnancy and the epidemiology, risk factors, diagnostic imaging, or treatment of VTE.

Results

Venous thromboembolism risk increases throughout pregnancy and peaks shortly after delivery. More than half of pregnancy-related VTE are associated with thrombophilia; other major risks include cesarean delivery, postpartum infection, and the combination of obesity with immobilization. Most VTE can be treated with low molecular weight heparin, but cases of limb- or life-threatening VTE require consideration of thrombolysis and other reperfusion therapies.

Conclusions and Relevance

Venous thromboembolism is far more frequent in antepartum and postpartum women than age-matched controls, and clinical suspicion for VTE in this population should incorporate pregnancy-specific risks. Treatment of limb- or life-threatening antepartum or postpartum VTE requires multispecialty coordination to optimize maternal and fetal outcomes.