Detecting PE in Pregnancy
                        =========================
þ Used to be:
 - before 16 weeks at Mercy, 20 weeks at Magee
  + do VQ instead of CT
  + do with half-dose perfusion injection (that's all you need as the lungs
    are compressed)
  + have the patient urinate frequently (or place a Foley) to keep the
    excreted radiation away from the fetus.
 - after 16 weeks at Mercy (20 weeks at Magee) do CT angio

þ Now (2007):
 - Do CT in all trimesters. With current scanners, less radiation to fetus,
   and less risk.
 - Only caveat is that if done in first trimester, concern about
   hypothyroidism of fetus at birth, so OB and pediatrician need to know about
   this.
   [CEM Journal Club, 4/07]