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Sagittal and axial HASTE fetal MR Images (A) at 25 weeks gestation shows a giant venous lake located at the torcular herophili and posterior superior sagittal sinus (arrows). There is two-intensity (inner hyperintense and outer hypointense) thrombus posteriorly and inferiorly (arrowheads). Sagittal and axial T2W postnatal MR images (B) at birth shows that the posterior collection compresses the cerebellum, resulting in herniated tonsils and brainstem (arrow). There is increased volume of stratified/concentric thrombus (arrowhead) which now occupies the entire volume of the torcular dural sinus malformation (tDSM). Also noted is hydrocephalus (arrow).
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A follow up fetal MRI at 25 weeks of gestation demonstrated a partially thrombosed dural venous sinus malformation with mass effect on the adjacent cerebral/cerebellar parenchyma with noncommunicating hydrocephalus and effacement of the prepontine cistern (Figure 1A). The cerebellar tonsils were displaced 9 mm below the foramen magnum (Figure 1B).
(A) Postnatal MR venogram shows absent flow within the collection (arrow) and subsequent catheter directed cerebral venogram at 3 months of age confirms spontaneous thrombosis of the torcular lake (arrow). (B) Axial T2W MRI at 3 monthes (left), 12 months (middle), and 30 months (right) of age shows progressive spontaneous involution of the thrombosed torculer lake with venous system remodeling (arrows). Evidence of a brain injury is present with ventriculomegaly and mild to moderate cerebral periventricular white matter and mild cerebellar volume loss (not shown).
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However, the neurovascular imaging showed that the malformation had spontaneously thrombosed and involuted (Figure 2A).
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