Case Notes
History
53 year old female who presented with acute onset diplopia and imaging evidence of dural sinus thrombosis affecting the torcular herophile, the left mesial transverse sinus, and the parietal segment of the SSS. Patient had evidence of meningitis and right sigmoid region epidural abscess. Patient was treated medically and with a right mastoidectomy. This patient is being reimaged at 10 days after the initial imaging.Exam
MR flair sequence
Purpose
Assess the FLAIR sequences for parenchymal edema in a recognizable venous egress zone(s).
Assess whether concurrent zones of edema are located on either side of a dural sinus, which is evidence that there is or has been thrombosis of that segment of the dural sinus.
Assess for positive FLAIR signal in the walls of recanalized cortical veins, the dural sinus walls, or the outer dura itself.
Assess for global or hemisheric swelling, since CVT can produce either pseudotumor type of brain swelling or hydrocephalus if extensive enough.
Assess for evidence of dilatation of the intraorbital veins, and optic hydrops (dilated CSF space around the optic nerves).
FLAIR is the best means of detecting early hydrocephalus, because it not only detects early ventriculomegaly, but also evidence of transepenymal fluid, effacement of sulci, increased protein in sulci. These feature help distinguish early CSF pressure elevation from chronic, incidental, ventriculomegaly.
Purpose
Assess the FLAIR sequences for parenchymal edema in a recognizable venous egress zone(s).
Assess whether concurrent zones of edema are located on either side of a dural sinus, which is evidence that there is or has been thrombosis of that segment of the dural sinus.
Assess for positive FLAIR signal in the walls of recanalized cortical veins, the dural sinus walls, or the outer dura itself.
Assess for global or hemisheric swelling, since CVT can produce either pseudotumor type of brain swelling or hydrocephalus if extensive enough.
Assess for evidence of dilatation of the intraorbital veins, and optic hydrops (dilated CSF space around the optic nerves).
FLAIR is the best means of detecting early hydrocephalus, because it not only detects early ventriculomegaly, but also evidence of transepenymal fluid, effacement of sulci, increased protein in sulci. These feature help distinguish early CSF pressure elevation from chronic, incidental, ventriculomegaly.
Prior Study
Initial admission imaging Initial imaging at the time of presentation demonstrated right coalescent mastoiditis, evidence of meningitis and dural sinus thrombosis affecting the torcula, left transverse sinus and the parietal segment of the SSS. There was a punctate area positive on both FLAIR and MR diffusion in the left superior vermic area (possible ischemic event). The right sigmoid sinus was partially compressed by a small epidural abscess, but was otherwise patent.CT head
Acute thrombus has progressed and is now evident in most of the superior sagittal sinus (SSS), the straight sinus, the torcular herophile, the right transverse sinus and the initial segment of the left transverse sinus. The hydrocephalus seen on initial imaging has resolved.
CT perfusion: No CT perfusion imaging is available
CTV of the neck: No neck CTV imaging was available
MRV of the head There are progressive dural CVT changes (compared to the initial MRV) with widespread dural sinus thromboses (SSS, torcula, and both transverse sinuses). The lateral aspect of the left transverse sinus wall is opacified but drains not through its' lumen to the sigmoid sinus, but rather into dural emissary channels. There is no apparent cortical vein thrombosis. The major veins are all patent; the vertex veins interconnect across the midline through the vertex venous lacunae. The pial/dural anastomoses combine with expanded dural wall venous plexes, and opened emissary venous channels to provide the dominant means of cerebral venous egress in this case, where there is thrombosis of both sigmoid sinuses.
Post contrast head CT No post contrast CT was available
Pre and post contrast T1-w MR
There are multiple dural sinus thromboses, as above, without cortical vein occlusions. There is reasonably functional collateral venous drainage is present utilizing expansion of the dural wall venous plexes, the left lateral tentorial venous confluence connected to the superior sylvian venous plexus egress route. The major venous egress routes for the deep central and subependymal veins appear to course through supra to infratentoral connections through the superior vermic vein and LAM collaterals ultimately draining into the petrosal veins. There is minimal evidence of persistently raised CSF pressure. There are expected post operative changes in the right mastoid area.
MR diffusion
Negative MR diffusion sequences; no completed venous stroke is evident.