(837) Vascular remodeling of the maternal cerebrovascular system

Pregnancy induces significant changes in the peripheral maternal vasculature, yet whether these changes are also present in the brain is unclear. Magnetic resonance angiography through Time Of Flight (MRA-TOF) technology allows high-resolution visualization of the cerebral vasculature without the need of contrast agent. The purpose of this study is to investigate maternal intracerebral vessel diameters and intracerebral flow distribution during the third trimester of pregnancy.

Study Design:

Five pregnant women experiencing normal pregnancy voluntarily agreed to a MRA-ToF during the third trimester of their pregnancy. The scans took place in 2021 at the Centre Hospitalier Universitaire de Sherbrooke in Fleurimont, Quebec. The images of their main cerebral vasculature were analyzed using an automated software method (eICAB) and compared with 42 non-pregnant women from publicly available database. The mean diameters of each intracerebral vessel forming the Circle of Willis were collected. Statistical standard test was used for comparison.

Results:

The mean diameters of the maternal cerebral arteries demonstrated an increase of 23,9% for the internal carotids (4,62 ± 0,2 mm in pregnancy vs 3,73 ± 0,7 mm, p=0,0001), of 14,8% for the basilar (3,25 ± 0,5 mm vs 2,83 ± 0,6 mm, p=0,01), of 5,33% for the anterior (2,37 ± 0,1 mm vs 2,25 ± 0,6 mm, p=0,2) and of 9,4% for the middle cerebral arteries (2,78 ± 0,2 mm vs 2,54 ± 0,7 mm, p=0,01). However, a decrease of 4,11% was observed in the posterior cerebral artery with diameters of 2,10 ± 0,3 mm vs 2,19 ± 0,4 mm, p=0,3.

Conclusion:

Our preliminary results suggests that most cerebral arteries in the brain slightly dilate during pregnancy. A notable exception is the PCA, which tends to slightly constrict. This may be due to the stimulation of the nervous system in the posterior region, though further study will be needed to confirm these findings.

Overall, these results broaden our understanding of the physiological adaptations of maternal intracerebral vascular flow and distribution during normal pregnancy in the different brain areas.