Cerebrovascular Anomalies in the Fetus

Vein of Galen malformation with parenchymal injuries in a 35-week-old fetus. A, Axial T2 SSFSE shows a dilated median prosencephalic varix, falcine sinus, and torcular, as well as ventriculomegaly. B, Axial T2 SSFSE shows areas of cystic degeneration (black arrow) and T2 hyperintensity in the left frontal lobe (white arrow), representing venous ischemia. C, Neonatal coronal T2 image demonstrates progression of parenchymal involvement, with new areas of ischemic injury in the right frontal lobe and insula (white arrow) associated with moderate ventriculomegaly.

Parenchymal injuries in 2 fetuses with vein of Galen malformations. A, Axial DWI in a 31-week-old fetus shows restricted diffusion (white arrow) in the left temporal lobe. B, Coronal T2 SSFSE shows generalized volume loss, cystic change (black arrow), and T2 hyperintense signal (white arrows) related to encephalomalacia. C, Axial T2* echo-planar image in a different 24-week-old fetus shows hemorrhage in the left periventricular region.

Measurement of the mediolateral width of the falcine sinus for consideration of fetal intervention and postintervention imaging. A, Axial T2 image at 32 weeks soon after the initial diagnosis of VOGM, with intact parenchyma and mild ventriculomegaly. B, Axial T2 image at 34 weeks, just before fetal embolization, shows interval growth in sinus width. C and D, Coronal T2 images prefetal embolization and 1-day post embolization respectively, showing diminution in width of the falcine sinus, indicative of diminution in lesional flow.

Pial arteriovenous fistula in a 32-week-old fetus. A, Sagittal T2 SSFSE shows a flow void in the frontal interhemispheric region (arrow) that drains into the deep venous system and eventually into the torcular. B, Sagittal T2 SSFSE through the right hemisphere shows the prominent pial vessels (white arrows), congestion of medullary veins, and developing periventricular cystic change. C, Coronal T2 SSFSE shows right greater than left parenchymal cystic changes (arrow), related to encephalomalacia and associated mild ventriculomegaly. D, Coronal T2* echo-planar image obtained 2 weeks later shows areas of blooming in the periventricular regions that correspond to areas of T1 shortening on (E) coronal T1 gradient-echo imaging (white arrows in D and E, respectively), related to venous congestion and subacute blood products.

Dural sinus malformation in a 33-week-old fetus. A, Sagittal T2 SSFSE shows marked dilation of the posterior aspect of the superior sagittal sinus and torcular. B, Sagittal DWI confirms the presence of clot within the dilated sinus (arrow). The brain parenchyma appears normal.

Dural sinus malformation in a 32-week-old fetus who was referred with a diagnosis of ventriculomegaly. A, Fetal sonography revealed a dilated dural sinus with internal echogenicity representing clot (black arrow). The echogenicity of the parenchyma was also abnormal (white arrow), with cystic changes and volume loss associated with severe ventriculomegaly. B, Axial T2 SSFSE shows severe parenchymal injury with cystic encephalomalacia (white arrows), severe ex vacuo ventriculomegaly, and intermediate signal from clot within the distended torcular (black arrow). C, Axial T1 gradient-echo shows blood products within the torcular that demonstrate T1 hyperintensity (black arrow).

Dural sinus malformation in a 33-week-old fetus. A, Fetal sonography with color Doppler shows turbulent flow within a dilated torcular. B, Axial T2 SSFSE shows an enlarged flow void in the region of the torcular, without signs of clot. There were no sonographic changes in the brain parenchyma. C, Axial T1 gradient-echo shows flow-related signal within enlarged external carotid arteries bilaterally (arrows). D, 3D maximum intensity projection from the postnatal time-of-flight MRA shows arterialized flow within the dural sinus malformations and middle meningeal and occipital artery feeders (arrows).