Imaging for PE in pregnancy

A review article on pulmonary embolism in pregnancy reminds us that the mortality associated with untreated PE far outweighs the potential oncogenic and teratogenic risk incurred by fetal exposure to diagnostic imaging for PE.
The minimum dose of radiation associated with increased risk of teratogenicity in human beings has yet to be firmly established, but on the basis of compiled mouse, rat, and human data, radiation exposure of 0·1 Gy at any time during gestation is regarded as a practical threshold beyond which induction of congenital abnormalities is possible.
An exposure of the conceptus to 0·01 Gy above natural background radiation increases the probability of cancer before the age of 20 years from 0·03% to 0·04%.
Reassuringly, a chest radiograph, ventilation perfusion scan, and conventional pulmonary angiogram combined with CT pulmonary angiogram expose the fetus to a total of 0·004 Gy.
Pulmonary embolism in pregnancy
Lancet. 2010 Feb 6;375(9713):500-12