Seven-year trends in computed tomography (CT) pulmonary angiography utilisation and predictors of positivity in a large emergency department

AIM: To evaluate trends in computed tomography pulmonary angiography (CTPA) utilisation in an emergency department (ED) and identify factors associated with pulmonary embolism (PE) detection. MATERIALS AND METHODS: This retrospective study analysed CTPA exams from 2017-2023 at a quaternary urban ED. CTPA volumes were normalised to total ED visits and ED CTs. Logistic regression assessed predictors of positivity. CTPA-per-visit trends were modelled with negative-binomial regression. RESULTS: CTPA volume rose 49% from 2,467 in 2017 to 3,684 in 2023. Positivity rates remained stable (mean 9.1%, range 8.3%-10.6%, p=0.55). CTPA use peaked at 10.0% of ED CTs in 2021, declining to 8.3% by 2023 (p=0.30). CTPAs per 1,000 ED visits increased from-22 in 2017 to-40 in 2021, then fell to-31 in 2023 (p=0.75). Male patients had higher odds of a positive result (aOR 1.222, 95% CI: 1.115-1.339), as did Black (aOR 1.222, CI: 1.058-1.412) vs White patients. Asian patients had lower odds (aOR 0.647, CI 0.489-0.857). Overnight exams were less likely to yield PE (aOR 0.830, CI 0.730-0.945). Higher body mass index (BMI) (aOR 1.014, CI 1.006-1.022) and cancer history (aOR 1.185, CI 1.039-1.352) were also predictive. Ordering provider training level (MD/DO, NP, PA) did not affect diagnostic yield. CONCLUSION: Over a seven-year period (2017-2023), annual CTPA volume and utilisation rate increased, but the positivity rate remained stable at-9%. Male sex, Black race, higher BMI, cancer history, and daytime imaging were associated with higher odds of PE. Provider training level was not associated with diagnostic yield. (c) 2025 The Royal College of Radiologists. Published by Elsevier Ltd. All rights are reserved, including those for text and data mining, AI training, and similar technologies.