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Flashcards in Imaging in pregnancy Deck (22):
1

Initial modality of choice for suspected appendicitis

Ultrasonography

2

2nd choice modality for suspected appendicitis

MRI or CT

3

Initial modality of choice for suspected PE

CT

4

Initial modality of choice for renal colic

Ultrasonography

5

Initial modality of choice for trauma

US, but CT if serious injury suspected

6

Is it safe to continue breastfeeding after iodinated contrast?

Yes

7

Is it safe to continue breastfeeding after gadolinium?

Yes

8

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

9

When is the fetus most susceptible to teratogenic effects of ionizing radiation?

Btw 2nd and 20th week of embryonic age

10

What are the teratogenic effects of ionizing radiation?

Microcephaly, microphthalmia, mental retardation, growth restriction, behavior defects, cataracts

11

Estimated threshold radiation dose below which no teratogenic effects occur

Not exactly knonw, but btw 5 & 15 rads

12

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

13

Baseline risk of fatal childhood cancer, RR after exposure to 5 rads

Baseline = 1/2000
Relative risk = 2

14

Radiation dose to fetus from abdominal xray

0.1-0.3 rads

15

Radiation dose to fetus from IVP

0.6 rads

16

Radiation dose to fetus from barium enema

0.7 rads

17

Radiation dose to fetus from lumbar spine x-ray

0.6 rads

18

Intraamniotic iodine contrast vs IV

Intraamniotic - potential to produce neonatal hypothyroidism
IV - reported to have no effect on neonatal thyroid fxn

19

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

20

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

21

How often will US correctly visualize obstructive urinary calculi?

Approximately 60% of the time.

22

Source

Chen, et al 2008