Advanced Imaging in Suspected Antenatal Pulmonary Embolism in Community Practice: Preferences, Indeterminacy, and Clinician Response.

Background: Which advanced imaging modality-computed tomography pulmonary angiography (CTPA) or lung scintigraphy-is optimal to evaluate for suspected pulmonary embolism (PE) in pregnancy is debated. Practice patterns, prevalence of indeterminate imaging, and clinician response in contemporary community hospitals are not well understood.

Methods: This retrospective cohort study included gravid adults in the emergency department (ED) and Labor and Delivery units (LDUs) who underwent advanced PE imaging 10/1/2021-3/31/2023. We excluded patients with COVID-19. Physician preferences were compared overall and in the subset of scintigraphy-eligible cases, i.e., those with imaging ordered when scintigraphy was available (7:00 a.m.-5:00 p.m.) and not contraindicated by abnormalities on chest radiography (CXR). We reported 48-h incidence of post-indeterminacy imaging and 90-day incidence of venous thromboembolism (VTE).

Results: Among 315 eligible cases, the median patient age was 31.0 years (IQR 26.5-35.5) with 164 (52.1%) in the third trimester. Index images included 288 (91.4%) CTPA and 27 (8.6%) scintigraphy, 25 of which were low-dose perfusion scans. PE was diagnosed in 5 (1.6%), all by CTPA. Among 116 scintigraphy-eligible cases, CTPA was favored: 82.8% versus 17.2%, with similar patterns between ED and LDU clinicians. CTPA diagnosed pneumonia in 6 cases (2.1% of 288) not previously identified on CXR and excluded pneumonia in 5 cases in which CXR suggested consolidation. Indeterminacy was more common with non-positive CTPA (24.7% [70/283]) than non-positive scintigraphy (0% [0/27]), p < 0.001. Only 7.1% (5/70) of patients with suboptimal non-positive CTPA received advanced imaging within 48 h, and none of the remaining 65 patients developed VTE or died within 90 days.

Conclusions: In this multicenter community setting with a low prevalence of PE, CTPA was preferentially ordered over lung scintigraphy in both the ED and LDU, even when both modalities were available and indicated. Indeterminate results were more prevalent with CTPA and often failed to trigger additional advanced imaging.