Chest CT in the Emergency Department for Diagnosis of COVID-19 Pneumonia: Dutch Experience.

Background Clinicians need to rapidly and reliably diagnose coronavirus disease 2019 (COVID-19) for proper risk stratification, isolation strategies, and treatment decisions. Purpose To assess the real-life performance of radiologist emergency department chest CT interpretation for diagnosing COVID-19 during the acute phase of the pandemic, using the COVID-19 Reporting and Data System (CO-RADS). Materials and Methods This retrospective multicenter study included consecutive patients who presented to emergency departments in six medical centers between March and April 2020 with moderate to severe upper respiratory symptoms suspicious for COVID-19. As part of clinical practice, chest CT scans were obtained for primary work-up and scored using the five-point CO-RADS scheme for suspicion of COVID-19. CT was compared with severe acute respiratory syndrome coronavirus 2 reverse-transcription polymerase chain reaction (RT-PCR) assay and a clinical reference standard established by a multidisciplinary group of clinicians based on RT-PCR, COVID-19 contact history, oxygen therapy, timing of RT-PCR testing, and likely alternative diagnosis. Performance of CT was estimated using area under the receiver operating characteristic curve (AUC) analysis and diagnostic odds ratios against both reference standards. Subgroup analysis was performed on the basis of symptom duration grouped presentations of less than 48 hours, 48 hours through 7 days, and more than 7 days. Results A total of 1070 patients (median age, 66 years; interquartile range, 54-75 years; 626 men) were included, of whom 536 (50%) had a positive RT-PCR result and 137 (13%) of whom were considered to have a possible or probable COVID-19 diagnosis based on the clinical reference standard. Chest CT yielded an AUC of 0.87 (95% CI: 0.84, 0.89) compared with RT-PCR and 0.87 (95% CI: 0.85, 0.89) compared with the clinical reference standard. A CO-RADS score of 4 or greater yielded an odds ratio of 25.9 (95% CI: 18.7, 35.9) for a COVID-19 diagnosis with RT-PCR and an odds ratio of 30.6 (95% CI: 21.1, 44.4) with the clinical reference standard. For symptom duration of less than 48 hours, the AUC fell to 0.71 (95% CI: 0.62, 0.80; P < .001). Conclusion Chest CT analysis using the coronavirus disease 2019 (COVID-19) Reporting and Data System enables rapid and reliable diagnosis of COVID-19, particularly when symptom duration is greater than 48 hours. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by Elicker in this issue.

Risk of atherothrombotic events in patients after proximal deep-vein thrombosis.

Several studies have shown high incidence of atherothrombotic events (ATEs) in patients with unprovoked pulmonary embolism. This association remains understudied in patients presenting with deep-vein thrombosis (DVT). We evaluated the risk factors for and the incidence of ATEs in patients with unprovoked proximal DVT, and compared it to patients with provoked DVT and reference patients without DVT. Patients with compression ultrasonography (CUS)-proven unprovoked proximal DVT, provoked DVT, and symptomatic patients in whom DVT was excluded by CUS were followed and scored for the occurrence of ATEs. A total of 1235 patients were enrolled: 170 patients with provoked, 74 patients with unprovoked DVT, and 991 patients without DVT. During follow-up, 128 ATEs occurred (incidence 6.5/100 patient-years). Adjusted hazard ratio was not different between patients with DVT and without DVT [hazard ratio 1.4; 95% confidence interval (CI) 0.76-2.4]. In contrast, patients with unprovoked DVT suffered from ATEs more frequently than provoked DVT patients (hazard ratio 3.16; 95% CI 1.1-9.1) and reference patients (hazard ratio 2.8; 95% CI 1.3-5.7). Notably, when fully adjusted for the known ATE risk factors, the risk differences between references, provoked, and unprovoked DVT patients diminished: hazard ratio 1.1 (95% CI 0.47-2.5) and 1.7 (95% CI 0.80-3.6), respectively. Our study confirms that the risk of ATEs in patients with unprovoked DVT was higher than in those with provoked DVT or reference patients. Interestingly, our results raise the question whether the known risk factors for ATE and venous thromboembolism attribute equally in pulmonary embolism and DVT patients, and contradict a causal relation between ATE and proximal DVT.