Predictors of radiation dose for CT pulmonary angiography in pregnancy across a multihospital integrated healthcare network.
There is a large range of published effective radiation dose for CTPA during pregnancy. The purpose of our study is to determine the mean effective radiation dose and predictors of mean effective radiation dose for CTPA in pregnant patients across a multihospital integrated healthcare network. This retrospective study evaluates pregnant women who had a CTPA as the first primary advanced imaging test for evaluation of PE in a multihospital integrated healthcare network from January 2012-April 2017. Patient and CT-related data were obtained from the electronic health record and Radimetrics server (Radimetrics Inc, Bayer). DLP was recorded and effective radiation dose in mSv was determined using a conversation factor of 0.014 mSv·mGy-¹·cm-¹. Patient size was determined by water equivalent diameter. Bivariate and multivariate analysis were performed for effective radiation dose based on patient and CT factors. In the 534 CTPA exams, the mean effective radiation dose was 3.96 mSv. Bivariate analysis showed significant differences in radiation dose by trimester, p = 0.042: first trimester 4.52 mSv, second trimester 3.73 mSv, and third trimester 3.95 mSv. Multivariable analysis demonstrated CTPA during first trimester, increasing mAs, kVp, scan length, patient size, and use of mAs modulation, as well as decreasing pitch, to be predictive of higher effective radiation dose. Mean effective radiation dose was on the lower end of published studies. Trimester was a statistically significant predictor of effective radiation dose when accounting for known predictors of radiation dose.