September 28, 2011 by dailybolusoflr
Investigating PE in Pregnancy
· The decision as to which imaging test to perform to diagnose PE in pregnancy is typically based on the ALARA principle. This motto of “as low as reasonably achievable” helps a physician to decide priority of imaging studies in this patient population. This is referring to the radiation dose for the mother and fetus.
· VQ scanning and Chest CT are the two main options for diagnosing PE.
· Alternative techniques of CXR and compression ultrasonography have been advocated as first line evaluation (and offer no radiation delivery to the mother or fetus), but when normal, do not offer a diagnosis nor rule out a PE.
· Multiple sources note that Chest CT offers a lower radiation dose to the fetus than VQ scan and thus should be considered first line for this diagnosis. Compounding this is the high rate of indeterminate VQ necessitating further study.
· Note that CT scan offers radiation to maternal breast tissue, in younger aged patients – those of child bearing age- and the increased risk of breast cancer in the mother should be considered.
Ref: Obstet Gyn 2008; 112:333-40 and BMJ 2007; 334: 418-419