Performance of Low-Dose Perfusion Scintigraphy and CT Pulmonary Angiography for Pulmonary Embolism in Pregnancy

2019 ESC Guidelines for the diagnosis and management of acute pulmonary embolism developed in collaboration with the European Respiratory Society (ERS)

“…A normal perfusion scan and a negative CTPA appear equally safe for ruling out PE in pregnancy, as suggested by retrospective series [385,386,[402][403][404]. Inconclusive results can be a problem (4-33% of investigations) [385,386,405], especially late in pregnancy [405]. A recent survey of 24 sites in the UK, representing a population of 15.5 million, revealed a similar rate of inadequate or indeterminate CTPA and scintigraphy scans, suggesting that the initial choice of imaging is best determined by local expertise and resources [406].…”

“…Diagnosis of PE during pregnancy can be challenging as symptoms frequently overlap with those of normal pregnancy. The overall prevalence of confirmed PE is low among women investigated for the disease, between 2 and 7% [385][386][387][388]. D-dimer levels continuously increase during pregnancy [389,390], and levels are above the threshold for VTE "rule-out" in almost one-quarter of pregnant women in the third trimester [390].…”

“…A proposed algorithm for the investigation of suspected PE in women who are pregnant, or ⩽6 weeks post-partum, is shown in figure 7. Both maternal and fetal radiation exposure are low using modern imaging techniques (table 12) [385,[392][393][394][395][396][397][398]. For V/Q scans and CTPA, fetal radiation doses are well below the threshold associated with fetal radiation complications (which is 50-100 mSv) [399,400].…”

“…The effect on maternal cancer risk with modern CTPA techniques is negligible (lifetime cancer risk is reportedly increased by a factor of 1.0003-1.0007); avoiding CTPA on the grounds of maternal cancer risk is therefore not justified [394]. A normal perfusion scan and a negative CTPA appear equally safe for ruling out PE in pregnancy, as suggested by retrospective series [385,386,[402][403][404]. Inconclusive results can be a problem (4-33% of investigations) [385,386,405], especially late in pregnancy [405].…”

“…In a pregnant patient with suspected PE (particularly if she has symptoms of DVT), venous CUS should be considered to avoid unnecessary irradiation [388]. B IIa Perfusion scintigraphy or CTPA (with a low-radiation dose protocol) should be considered to rule out suspected PE in pregnant women; CTPA should be considered as the first-line option if the chest X-ray is abnormal [385,386].…”