Pulmonary Embolism Evaluation in the Pregnant Patient: A Review of Current Imaging Approaches

CTPA allows definitive diagnosis of PE by demonstrating intraluminal filling defects within the pulmonary arteries (arrows). CTPA provides the added benefit of demonstrating other anatomical information that might be pertinent to the patient's clinical outcome, such as the presence of right heart dilatation in this example (asterisks).

A 29-year-old pregnant woman who presented with chest pain. Note the sharp, normal contours of the lungs in all 8 standard planar images of this normal perfusion scan. A normal or very low probability scan is very reassuring, with specificity approaching 100%. LT, left; RT, right; RPO, right posterior oblique; RAO, right anterior oblique; LPO, left posterior oblique; LAO, left anterior oblique.

Multiple large wedge-shaped perfusion defects in right lung (arrows) and decreased perfusion to large portion of left lung (asterisks), with sparing of the apicoposterior segment of the left upper lobe. Ventilation portion of this study and recent chest radiograph (not pictured) were both unremarkable. Findings are consistent with high probability for PE.

Coronal reconstructed image from CTPA in a pregnant woman demonstrates mixing of large influx of unopacified blood from IVC (arrow) and injected contrast bolus (asterisk). Contrast dilution from this phenomenon, owing to the hemodynamic effects of pregnancy, might lead to poor opacification of the pulmonary arteries and a greater number of indeterminate studies if preventative steps are not taken.

Axial CTPA image in 19-year-old pregnant woman demonstrates the patient's breast tissue directly within the scanned volume. CTPA delivers much greater radiation dose to the maternal breast than does lung scintigraphy. The potential increased risk for radiation-induced breast carcinoma should not be disregarded when deciding on method of diagnostic evaluation.