Pulmonary embolism - CTPA Vs V/Q scanning

• CTPA has better sensitivity and specificity (at least in nonpregnant women)  and a lower radiation dose to the fetus when compared to V/Q scan.


• CTPA can identify other pathology, such as aortic dissection.


• The main disadvantage of CTPA is the high radiation dose to the maternal breasts, which is associated with an increased lifetime risk of developing breast cancer.


• CTPA may not identify small peripheral PEs


• Despite these potential advantages of CTPA, many authorities continue to recommend V/Q scanning as first-line investigation in pregnancy because of its high negative predictive value in this situation and its substantially lower radiation dose to pregnant breast tissue