Flashcards in Imaging in pregnancy Deck (22)
Initial modality of choice for suspected appendicitis
2nd choice modality for suspected appendicitis
MRI or CT
Initial modality of choice for suspected PE
Initial modality of choice for renal colic
Initial modality of choice for trauma
US, but CT if serious injury suspected
Is it safe to continue breastfeeding after iodinated contrast?
Is it safe to continue breastfeeding after gadolinium?
Risk of of SAB with CT
Within 1st 2 weeks of embryonic age, there is a risk of failure of blastocyst to implant when irradiation dose is > 10 rads, but likely no increased risk if embryo survives
When is the fetus most susceptible to teratogenic effects of ionizing radiation?
Btw 2nd and 20th week of embryonic age
What are the teratogenic effects of ionizing radiation?
Microcephaly, microphthalmia, mental retardation, growth restriction, behavior defects, cataracts
Estimated threshold radiation dose below which no teratogenic effects occur
Not exactly knonw, but btw 5 & 15 rads
Radiation dose to fetus from CT pelvis
Ranges from 2.4 rad in 1st trimester to 4.6 rad in 3rd trimester
Other articles quote 1-4.5 rad
Baseline risk of fatal childhood cancer, RR after exposure to 5 rads
Baseline = 1/2000
Relative risk = 2
Radiation dose to fetus from abdominal xray
Radiation dose to fetus from IVP
Radiation dose to fetus from barium enema
Radiation dose to fetus from lumbar spine x-ray
Intraamniotic iodine contrast vs IV
Intraamniotic - potential to produce neonatal hypothyroidism
IV - reported to have no effect on neonatal thyroid fxn
Is there a risk of acoustic injury to the fetus during prenatal MRI?
Follow up studies of children exposed to prenatal MRI suggest that acoustic damage during pregnancy is more of a theoretical than real concern - Chen 2008
Why should gadolinium only be used if absolutely essential?
Gadolinium crosses the placenta, where it is pre-sumably excreted by the fetal kid-neys into the amniotic fluid. In the era of gadolinium-induced nephro-genic systemic fibrosis, this raises theoretical concerns of toxicity re-lated to disassociation and persis-tence of free gadolinium
How often will US correctly visualize obstructive urinary calculi?
Approximately 60% of the time.