NEUROIMAGING

Neuroimaging During Pregnancy and Lactation

David Goldemund M.D.
Updated on 12/12/2023, published on 06/06/2022

  • ultrasound and magnetic resonance imaging (MRI) are not associated with increased risk and are the preferred imaging modalities for pregnant women (ACOG Guidelines 2017)
  • still, they should be used with caution (especially MRI) and only when their use is expected to answer a relevant clinical question or otherwise provide medical benefit to the patient
Fetal radiation dose caused by different diagnostic methods
Computed tomography (CT)
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Magnetic resonance imaging (MRI)

Exposure to non-contrast MRI

  • MRI is the preferred imaging modality in pregnancy, whether for maternal or fetal reasons.
  • using a 1.5 T scanner is recommended
  • to date, there are no known adverse effects or specific consequences for fetuses exposed to non-contrast MRI
    • published data indicate no increased risk of fetal malformations, even in the first trimester  [Ray, 2016]
    • there is a growing body of experience with fetal MRI (used to detect brain developmental defects, placental abnormalities, and more) [Griffiths, 2005]

Exposure to gadolinium-based contrast agent (GBCA)

Pregnancy

  • gadolinium contrast agents should be avoided (particularly during the period of organogenesis) unless essential to address a relevant clinical question
    • gadolinium crosses the placenta and has a significantly prolonged elimination from the fetal circulation with a risk of deposition in fetal tissues
    • animal studies indicate teratogenicity with high and repeated doses of IV gadolinium
    • analyze the risk-benefit; the patient must give informed consent after a discussion of risks and benefits
    • in vascular neurology, contrast administration can be avoided by using time-of-flight (TOF) sequences
    • if contrast agent administration is necessary, prefer macrocyclic GBCAs with the lowest feasible dose [Copel, 2017]

Lactation

  • there is a limited excretion of GBCAs into breast milk (< 0.04% in the first 24 hours, and the infant absorbs < 1%)  [Copel, 2017]
  • GBCAs should only be used when clinically necessary and non-postponable
  • there is no proven benefit of interrupting breastfeeding after GBCAs administration
Neurosonology
  • neurosonology is safe for both the mother and the fetus, and it is the preferred method for diagnosing and monitoring occlusions and stenoses during pregnancy
  • ultrasound is also a safe method for examination of the fetus, but the ALARA principle should be followed regarding the amount of energy used (max. intensity < 720 mW/cm2)
    • the thermal effect on the fetus is highest with the color and Doppler mode and lowest with the B mode
    • it’s advisable to use obstetric presets for these examinations
Angiography (DSA)
  • DSA is mostly reserved for interventional procedures, such as mechanical thrombectomy (MT), aneurysm coiling, etc.
    • pregnant women were excluded from randomized trials with MT, but the benefit can be assumed ⇒ pregnancy is, therefore, a relative contraindication to MT
    • published case reports have shown favorable maternal and fetal outcomes [Blythe, 2019]
  • careful fetal shielding with a lead apron is essential during such procedures

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Neuroimaging during pregnancy and lactation
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