AJR 2005; 184:1317-1319
© American Roentgen Ray Society
Imaging of Cerebral Isolated Cortical Vein Thrombosis
Ian C. Duncan and
Pieter A. Fourie
Unitas Interventional Unit, Centurion, PO Box 14031, Lyttelton 0140,
South Africa.
Received May 14, 2004;
accepted after revision July 20, 2004.
Address correspondence to I. C. Duncan
(docdunc{at}iafrica.com).
Introduction
Isolated cortical venous thrombosis is less commonly encountered
than dural sinus thrombosis. It is difficult to diagnose either clinically or
radiologically, and its detection on sectional imaging depends primarily on
visualizing the thrombosed vein (cord sign) and secondarily on visualizing any
associated hemorrhage or venous infarction. On angiography, all that may be
seen is vascular congestion in the region of drainage of the occluded vein
because the thrombosed vein itself often does not opacify. These imaging
features are well illustrated in this case report together with the
visualization of associated transient dural arteriovenous fistula induced by
the thrombosis of the affected cortical vein.
Case Report
A 21-year-old woman presented with an 8-hr history of slowly progressive
weakness and sensory loss in the right arm and upper trunk that was later
accompanied by headaches and vomiting and a focal seizure of the right arm.
She had suffered similar episodes of transient neurologic symptoms affecting
the right upper limb during the preceding 3 years. She had no history of deep
venous thrombosis but had a renal vein thrombosis diagnosed at 18 months of
age. The only other relevant risk factor was a 6-month history of oral
contraception use.
A CT scan obtained on day 1 showed hemorrhage within and adjacent to the
left central sulcus (Fig. 1A).
An unenhanced MR image obtained on day 2 showed edema in the adjacent
precentral and postcentral gyri and underlying white matter
(Fig. 1B). There was no
sagittal sinus thrombosis noted on MR venography; however, on the cerebral
surface adjacent to the affected area of the brain was a prominent blood
vessel initially reported as showing a flow void by virtue of its hypointense
appearance on T2-weighted images (Fig.
1C). The same vessel was seen to be isointense with brain on
unenhanced T1-weighted images. Gadolinium was not administered.
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Fig. 1A. —21 year-old woman with rapidly progressive neurologic deficit
in her right arm followed by a grand mal seizure. Axial unenhanced CT scan
obtained on day 1 shows acute hemorrhage within central sulcus.
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Fig. 1B. —21 year-old woman with rapidly progressive neurologic deficit
in her right arm followed by a grand mal seizure. Axial FLAIR MR image
obtained on day 2 shows hemorrhage in and edema around central sulcus.
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Fig. 1C. —21 year-old woman with rapidly progressive neurologic deficit
in her right arm followed by a grand mal seizure. Coronal T2-weighted image
also obtained on day 2 shows hypointense vein over left cerebral hemisphere
(arrows).
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Due to the suspicion of the presence of a high-flow vascular malformation
as the cause of the bleed, cerebral digital subtraction arteriography was
performed; these images did not show any pial arteriovenous shunt but did show
a small dural fistula to the left of the midline in the frontoparietal region
filling from a single branch of the anterior division of the left middle
meningeal artery (Fig. 1D). The
patient was then referred 1 week later to our unit for embolization of this
dural shunt.
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Fig. 1D. —21 year-old woman with rapidly progressive neurologic deficit
in her right arm followed by a grand mal seizure. Selective left external
carotid digital subtraction obtained 1 day after B and C
arteriogram shows small transient dural arteriovenous shunt filling from
branch of anterior division of left middle meningeal artery.
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During the initial repeat cerebral arteriography, the dural shunt was now
no longer seen, but a selective left internal carotid arteriogram showed a
strip of venous congestion around the left paracentral region
(Fig. 1E). No sinus thrombosis
was seen. A provisional diagnosis of cortical venous thrombosis was made, and
treatment was commenced with low-molecular-weight heparin.
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Fig. 1E. —21 year-old woman with rapidly progressive neurologic deficit
in her right arm followed by a grand mal seizure. Selective left internal
carotid digital subtraction arteriogram obtained 1 week after D shows
strip of venous congestion in paracentral region (arrows) with dural
shunt no longer seen.
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A second MR image obtained on day 11 showed the enlarged surface vessel to
be homogeneously hyperintense on FLAIR unenhanced and T1-weighted images
(Figs. 1F and
1G, respectively). Both the
hemorrhage and the edema were also seen to be resolving. A retrospective
review of an MR image obtained after a similar neurologic episode 2 years
earlier showed this same vessel to be a normally enhancing cortical vein,
further confirming the diagnosis of a recent isolated cortical vein
thrombosis.
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Fig. 1F. —21 year-old woman with rapidly progressive neurologic deficit
in her right arm followed by a grand mal seizure. Axial FLAIR MR image
obtained on day 11 at same level as B now shows hyperintense signal
within thrombosed cortical vein (arrow).
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Fig. 1G. —21 year-old woman with rapidly progressive neurologic deficit
in her right arm followed by a grand mal seizure. Sagittal unenhanced
T1-weighted MR image also obtained on day 11 shows hyperintense signal within
thrombosed vein (arrow).
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No underlying thombotic disorder was un-covered during further
investigation. Treatment consisted of low-molecular-weight heparin initially
followed later by conversion to oral warfarin sodium (Lennon-Warfarin, Aspen
Pharmacare) therapy. The patient made a complete recovery from her neurologic
deficits and remains well 9 months later.
Discussion
Isolated cortical venous thrombosis is encountered less commonly than dural
sinus thrombosis and is more difficult to diagnose both clinically and
radiologically
[1-3].
The neuroimaging features of cerebral venous thrombosis can be divided into
direct signs—that is, visualization of the thrombus—and indirect
signs such as hemorrhage or venous infarction. Visualization of a hyperintense
clot within a thrombosed cortical vein on CT scans gives rise to the cord sign
[4]. The MR equivalent of the
cord sign can be difficult to identify, particularly during the acute stage of
thrombosis when the clot tends to be isointense with brain on T1-weighted
images and hypointense on T2-weighted images where it mimics a flow void.
From 3 to 7 days after thrombosis, the clot becomes hyperintense on both
T1- and T2-weighted images and is thus easier to identify. Analysis of the
source images of an MR venogram also may assist in identifying a
"missing" cortical vein
[5]. Because of the extreme
variability of the number and position of the cortical veins, isolated
cortical vein thrombosis—that is, nonfilling of a cortical
vein—may be missed during cerebral catheter angiography. However, what
may be seen, as in our patient, is focal venous congestion and collateral
venous pathways, a localized form of the so-called "pseudophlebitic
pattern" [5].
Focal intracerebral hemorrhages can be caused by a number of underlying
abnormalities including intracranial vascular malformations (arteriovenous
malformation, cavernous malformation), dural arteriovenous fistula, hemorrhage
associated with infarctions or tumors, cerebral arteritis, aneurysm rupture,
and dural sinus thrombosis. Some hemorrhages may result from underlying
hypertension, coagulopathy, infection, or trauma, whereas others are deemed
"idiopathic" or "of undetermined cause." Because of
the difficulty in diagnosing isolated cortical vein thrombosis, some of the
so-called idiopathic cases may well be caused by this problem. MRI is useful
in identifying vascular malformations, infarctions, or tumors, and MR
angiography is able to detect aneurysms, vasculitis, and dural sinus
thrombosis. Certain abnormalities may not be detected by either CT or MRI,
thereby requiring conventional angiography for their exclusion. These include
subtle vasculitic changes, very small arteriovenous malformations, and some
dural arteriovenous shunts.
Of further interest in our case was the transient development of a small
dural arteriovenous fistula in the vicinity of the thrombosed vein. There is a
known association between the presence of cerebral venous thrombosis and the
development of a dural shunt. The theory is that the induction of a dural
shunt may be triggered by an event that promotes angiogenesis within the dura
such as infection, trauma, and venous thrombosis
[6]. Conversely, spontaneous
occlusion of an existing dural shunt may also occur due to thrombosis of its
venous outlet and retrograde extension of the thrombus into the shunt vessels.
This thrombosis may, however, result in the development of new neurologic
signs or intracranial hemorrhage either because of venous occlusion or due to
the diversion of flow into cortical veins in partially thrombosed shunts.
Although we cannot be certain, we suspect that the dural shunt in our case
was temporarily induced by the development of the thrombosis rather than being
a preexisting dural shunt that spontaneously thrombosed. We believe this
mainly because this shunt regressed spontaneously within 1 week despite the
persistence of the cortical vein thrombosis and because there was no evidence
of enlargement of the feeding meningeal artery to suggest a longer-standing
preexisting dural shunt.
In conclusion, isolated cortical venous thrombosis may be difficult to
diagnose both clinically and radiologically. MRI features may be difficult to
identify, particularly in the acute stages of thrombosis and especially when
associated indirect signs are absent. A high index of clinical suspicion and
the appropriate use and careful analysis of sectional imaging or angiography
(or both) are essential in confirming this diagnosis.
References
- Jacobs K, Moulin T, Bogousslavsky J, et al. The stroke syndrome of
cortical vein thrombosis. Neurology1996; 47:876
-882[Abstract/Free Full Text]
- Chang YJ, Huang CC, Wai YY. Isolated cortical venous thrombosis:
discrepancy between clinical features and neuroradiologic findings—a
case report. Angiology1995; 46:1133
-1138
- Park DC, Sohn YH, Lee PH. Neurologic deficits with isolated
cortical venous congestion. Neurology1999; 52:571
-572[Abstract/Free Full Text]
- Ahn TB, Roh JK. Cerebral venous thrombosis in adults: the role of
imaging evaluation and management. Arch Neurol2003; 60:1314
-1316[Abstract/Free Full Text]
- Lee SK, terBrugge KG. Cerebral venous thrombosis in adults: the
role of imaging evaluation and management. Neuroimaging Clin N
Am 2003;13:139
-152[Medline]
- Berenstein A, Lasjaunias P, terBrugge KG. Dural arteriovenous
shunts. In: Berenstein A, Lasjaunias P, terBrugge KG. Surgical
neuroangiography, vol. 2.2. Berlin,
Germany: Springer-Verlag, 2004:565
-607
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Introduction
Case Report
