Pulmonary embolism in pregnancy and the postpartum period: 16-Year trends in CT pulmonary angiography and lung scintigraphy.

OBJECTIVES

To evaluate 16-year trends in utilisation, radiation exposure, and diagnostic yield of computed tomography pulmonary angiography (CTPA) and lung scintigraphy (LS) for suspected pulmonary embolism (PE) during pregnancy and postpartum period.

MATERIALS AND

METHODS

Pregnant and ≤ 6-week postpartum patients undergoing CTPA or LS from 2008 to 2024 were retrospectively studied. CTPA maternal effective, breast absorbed and modelled foetal effective doses were estimated using Monte Carlo modelling. LS maternal effective, breast absorbed and foetal absorbed doses were calculated from administered activity using ICRP coefficients.

RESULTS

Of 1,140 imaging examinations, 945 occurred during pregnancy (619 LS; 326 CTPA) and 195 postpartum (33 LS; 162 CTPA). LS comprised 65.5% of pregnancy examinations but 16.9% postpartum compared with 34.5% and 83.1% for CTPA respectively (p < 0.001). CTPA use increased while LS use declined. During pregnancy, PE was detected in 16/619 LS examinations (2.6%) and 12/326 CTPAs (3.7%); postpartum, in 0/33 LS examinations and 11/162 CTPAs (6.8%). Median maternal effective doses during pregnancy were 0.544 mSv for LS (IQR 0.512-0.593, n = 449) and 2.96 mSv for CTPA (IQR 2.23-3.74, n = 305); postpartum effective doses were 1.126 mSv (IQR1.045-1.243, n = 10) and 1.69 mSv (IQR 1.43-2.42, n = 142), respectively. Breast absorbed dose was higher with CTPA during pregnancy and postpartum (both p < 0.001).

CONCLUSION

Over 16 years, imaging shifted from LS towards CTPA. Diagnostic yield remained low, as expected in a rule-out population, while CTPA was associated with higher maternal effective and breast absorbed doses than LS. These findings underscore the importance of appropriate imaging selection in this population.