Pulmonary embolism (PE) remains a significant cause of mortality requiring prompt diagnosis and risk stratification. This review focuses on the role of computed tomography (CT) in the risk stratification of acute PE, highlighting its impact on patient management. We will explore basic pathophysiology of pulmonary embolism (PE) and review current guidelines, which will help radiologists interpret images within a broader clinical context. This review covers key CT findings which can be used for risk stratification including indicators of right ventricular (RV) dysfunction, clot burden, clot location and left atrial volume. We will discuss the measurement of RV/LV diameter ratio as a key indicator of RV dysfunction and its limitations and challenges within various patient populations. While these parameters should be included in a radiologist's report, their predictive value for mortality depends on the patient's existing cardiopulmonary reserve and should not be interpreted in isolation.

Imaging of the thoracic aorta is a common request in both the acute and outpatient settings, playing a crucial role in diagnosis and treatment planning of aortic disease. The findings of aortic pathology may be obvious or occult on imaging. Recognizing subtle changes is essential and may lead to early detection and prevention of serious morbidity and mortality. Knowledge of the anatomy and understanding the pathophysiology of aortic disease, as well as selecting the appropriate imaging modality and protocol will enable prompt diagnosis and early intervention of aortic pathology. Currently, computed tomography angiography and magnetic resonance angiography of the aorta are the most commonly used imaging modalities to evaluate the aorta. This review focuses on a spectrum of aortic pathology manifestations on computed tomography and magnetic resonance, including atherosclerosis and acute aortic syndromes, highlighting diagnostic challenges and approaches to aid in image interpretation.

Background: Atypical manifestations of coronavirus disease 2019 (COVID-19) are being encountered as the pandemic unfolds, leading to non-chest CT scans that may uncover unsuspected pulmonary disease. Purpose: To investigate patients with primary nonrespiratory symptoms who underwent CT of the abdomen or pelvis or CT of the cervical spine or neck with unsuspected findings highly suspicious for pulmonary COVID-19. Materials and Methods: This retrospective study from March 10, 2020, to April 6, 2020, involved three institutions, two in a region considered a hot spot (area of high prevalence) for COVID-19. Patients without known COVID-19 were included who presented to the emergency department (ED) with primary nonrespiratory (gastrointestinal or neurologic) symptoms, had lung parenchymal findings suspicious for COVID-19 at non-chest CT but not concurrent chest CT, and underwent COVID-19 testing in the ED. Group 1 patients had reverse transcription polymerase chain reaction (RT-PCR) results obtained before CT scan reading (COVID-19 suspected on presentation); group 2 had RT-PCR results obtained after CT scans were read (COVID-19 not suspected). Presentation and imaging findings were compared, and outcomes were evaluated. Descriptive statistics and Fisher exact tests were used for analysis. Results: Group 1 comprised 62 patients (31 men, 31 women; mean age, 67 years 617 [standard deviation]), and group 2 comprised 57 patients (28 men, 29 women; mean age, 63 years 6 16). Cough and fever were more common in group 1 (37 of 62[60%] and 29 of 62 [47%], respectively) than in group 2 (nine of 57 [16%] and 12 of 57 [21%], respectively), with no significant difference in the remaining symptoms. There were 101 CT scans of the abdomen or pelvis and 18 CT scans of the cervical spine or neck. In group 1, non-chest CT findings provided the initial evidence of COVID-19-related pneumonia in 32 of 62 (52%)patients. In group 2, the evidence was found in 44 of 57 (77%) patients. Overall, the most common CT findings were ground-glassopacity (114 of 119, 96%) and consolidation (47 of 119, 40%). Major interventions (vasopress or medication or intubation) were required for 29 of 119 (24%) patients, and 27 of 119 (23%) died. Patients who underwent CT of the cervical spine or neck had worse outcomes than those who underwent abdominal or pelvic CT (P =.01). Conclusion: In a substantial percentage of patients with primary nonrespiratory symptoms who underwent non-chest CT, CT provided evidence of coronavirus disease 2019-related pneumonia. (C) RSNA, 2020

Pulmonary embolism is the third most common acute cardiovascular disease. Dual-energy computed tomography perfusion imaging is a promising adjunct in the detection of acute PE providing simultaneous functional assessment of pulmonary perfusion alongside the high-resolution morphological information from computed tomography pulmonary angiography. We review the evidence to date and common causes of perfusion defects including artifacts, parenchymal, and vascular causes, and discuss its potential in furthering our understanding of physiology and pathophysiology in acute pulmonary embolism.

•Many systemic childhood diseases present with skin manifestations.•Knowledge of the association of a characteristic dermatologic manifestation may aid the radiologist's diagnosis and help guide the imaging workup.•Awareness of characteristic dermatologic manifestations may aid the radiologist in confirming the diagnosis and guiding the imaging workup.•Epidermolysis bullosa and basal cell nevus syndrome are associated with the development of subsequent potentially fatal malignancies.•The first presentation of a primary malignancy such as Neuroblastoma or leukemia may beskin nodules or a rash.•Autoimmune diseases of childhood often have multisystem involvement, the identification of which may prevent disease complications.

Ventilation/perfusion (V/Q) scans are highly sensitive in detecting clinically significant pulmonary embolisms; however, V/Q mismatches are not specific to pulmonary embolism alone, and other etiologies can cause false-positive results. We present 3 cases where the pulmonary vasculature was compromised, from either intraluminal narrowing or external compression, with resultant mismatches. This raises the importance of interpreting V/Q scan results in conjunction with a thorough medical/surgical history and careful analysis of the chest radiograph.