American Journal of Neuroradiology 27:1315-1317, June-July 2006
© 2006 American Society of Neuroradiology
Case Report
HEAD AND NECK
Localized Congestive Venous Encephalopathy Associated with Cavernous Dural Arteriovenous Malformation
R.V. Phadkea,
A. Parihara,
S. Beharib and
K. Sharmac
a Departments of Radiodiagnosis, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India
b Neurosurgery, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India
c Neuro-ophthalmology Section, Department of Neurosurgery, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India
Address correspondence to Rajendra V. Phadke, Consultant Radiologist, Neurointervention, Royal Preston Hospital, Lancashire Teaching Hospitals NHS Foundation Trust, Sharoe Green Ln, Fulwood, Preston PR2 9HT, United Kingdom
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Abstract
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SUMMARY: An unusual case of venous congestive encephalopathy
associated with cavernous sinus dural arteriovenous malformation
is reported. The parenchymal changes consisted of a well-demarcated
area of hyperintensity on T2-weighted MR images involving the
cortex and underlying white matter in the ipsilateral temporal
and posterior frontal region. It showed mass effect and persisted
for 2 years before evolving into a venous infarction.
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Introduction
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Venous congestive encephalopathy has been well identified in
the last few years in patients with dural arteriovenous malformations
(DAVMs).
1-
3 The underlying venous hypertension mainly depends
on the volume of arteriovenous shunting through the fistula
and the resistance to venous outflow.
4 MR imaging has been very
useful in identifying parenchymal changes. DAVMs of the cavernous
sinus usually follow a benign course and significant parenchymal
changes and related clinical symptoms are rarely seen in these
lesions. Mild chemosis, proptosis, bruit, and extraocular muscle
palsies are the common presentations. We report a case of localized
congestive encephalopathy in a case of DAVM of the cavernous
sinus that initially posed a diagnostic difficulty and later
evolved into a chronic venous infarction.
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Case Report
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A 48-year-old woman was being treated for seizures and mild
chemosis/proptosis of the right eye for 3 months. She had been
diabetic for 15 years and was under treatment for mild hypertension
for the last 3 years. She had recurrent ptosis, diplopia on
right side, headache, and blurring of vision during the last
2 years. A CT scan performed 2 years earlier was essentially
normal.
Ophthalmic examination showed mild chemosis and proptosis of the right eye. There was no bruit over the eye or in the retroauricular region. Vision in the right eye was 6/9. The extraocular muscle movements were mildly restricted. There was no neurologic deficit in the limbs. A recent MR imaging showed an enlarged right cavernous sinus with flow void and a T2-hyperintense parenchymal lesion in the temporal and adjacent posterior frontal region (Fig 1A). Gyri in the affected region were swollen and hyperintense on T2-weighted images. Effaced sulci and mass effect on ipsilateral ventricle were seen. A focal T2 hyperintensity was also noted in the middle cerebellar peduncle on the right side (Fig 1B). Angiography was undertaken with a provisional diagnosis of cavernous carotid aneurysm and possibly a middle cerebral artery (MCA) branch territory infarction. Angiography showed a DAVM involving right cavernous sinus. It was fed by cavernous carotid branches as well as feeders from external carotid artery on the right side and minimal supply from the contralateral vessels. The right cavernous sinus was large. The venous drainage was restricted with only a mildly dilated right superior ophthalmic vein. The inferior petrosal sinus (IPS) was not shown. A prominent reverse drainage to sphenoparietal sinus and opacification of its cortical venous tributaries was seen (Fig 1C). The territory corresponded to the parenchymal lesion on MRI Partial reflux into the right superior petrosal sinus was also seen. A venous route approach for interventional treatment to the right cavernous sinus through IPS and also through angular vein failed. External carotid artery feeders were embolized with polyvinyl alcohol particles and the patient was asked to practice intermittent carotid compression as a therapeutic measure.
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Fig 1. A, Coronal T2-weighted image shows an enlarged right cavernous sinus with flow void and a right temporofrontal parenchymal hyperintense lesion. B, Axial T2-weighted image shows the enlarged right cavernous sinus, a right middle cerebellar peduncle lesion, and right-sided proptosis. C, Lateral view of right external carotid angiography shows the DAVM. The right cavernous sinus is large and predominantly draining into spheno-parietal sinus and its tributaries. D, T2-weighted MR image 9 months later shows increased mass effect from the parenchymal lesion. Corresponding DW image (E) and ADC map (F) with values ranging from 1.2 to 1.6 x 10–3 mm2/s. G, T2-weighted MR image 24 months later shows venous infarction in the affected region with resolution of mass effect. DW image (H) and ADC map (I) with values ranging from 1.0 to 2.1 x 10–3 mm2/s.
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Although arterial infarction was ruled out, at that stage the parenchymal lesion was not fully understood and ischemic/neoplastic processes were considered in differential diagnosis. The patient showed improvement in the eye signs. She underwent subsequent MR imaging 9 months later. The parenchymal lesion showed increase in size and mass effect and showed increased edema of the underlying white matter. Diffusion-weighted (DW) imaging was negative (Fig 1D–F). There were no new neurologic deficits, though an increase in the dose of antiepileptic drug was necessary in the intervening period. Eye signs suggested presence of residual DAVM. At this stage, the parenchymal lesion was suspected to be due to chronic venous insufficiency of the territory secondary to the DAVM. The patient refused any aggressive transorbital approach for interventional treatment or surgical treatment. Additional follow-up MR imaging 15 months later (24 months after the diagnosis was confirmed) showed regression in the size of the parenchymal lesion, the mass effect to have vanished, and the imaging was suggestive of chronic venous infarction in the affected territory (Fig 1G–I). The cavernous sinus returned to normal size and the right superior ophthalmic vein showed regression in size. The eye signs showed considerable resolution. The neurologic examination was within normal limits.
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Discussion
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DAVMs, often seen in the setting of chronic venous sinus occlusion,
may show 3 similar main patterns of parenchymal involvement
2:
(1) brain swelling without abnormal signal intensity on T2-weighted
images, (2) brain swelling with abnormal signal intensity on
T2-weighted images but no hematoma, and (3) parenchymal hematoma
and edema. Focal parenchymal enhancement, abnormal flow voids,
and demonstrable abnormal vessels on MRA may be seen.
2,5 In
addition the occluded venous sinus(es) can be shown on MR venography.
The first 2 patterns are regarded to be due to interstitial
edema secondary to cortical venous drainage (CVD) and related
venous congestion.
2 The site of parenchymal involvement may
be remote, and the changes reported are more diffuse in distribution.
1,2,4 Aggressive lesions are usually present with seizures, focal
deficits, cognitive impairment,
4 and, in some cases, hemorrhage.
Cortical venous reflux and/or stenosis of venous pathway are
usually present in such patients. CVD was seen in 22/118 (19%)
patients with DAVM of the cavernous sinus in a retrospective
study by Stiebel-Kalish et al.
6 Parenchymal changes other than
enhancement, however, were not discussed in that report. The
report suggests high probability of CVD in patients with bilateral
eye signs 12/28 (43%). All 7 patients with neurologic signs/symptoms
had CVD. Our patient had unilateral eye signs. In a series of
28 patients studied by Halbach et al,
7 only one patient had
cortical venous reflux to Sylvian vein. Pontine congestion related
to the perimesencephalic drainage has been reported earlier
in DAVM of the cavernous sinus.
8,9 Presentation with seizures,
a parenchymal lesion having a tumor-like MR imaging pattern,
and the changes persisting for 2 years were the unusual features
of our case with a cavernous sinus DAVM. Gyral swelling and
chronic nature of the lesion, however, indicated a pathology
other than tumor or arterial infarction, respectively. As has
been seen in venous ischemia,
10 DW imaging did not show any
evidence of cytotoxic edema at that time and the parenchymal
changes appeared to be related to venous hypertension, which
led to pressure-driven interstitial edema. Isolated reports
suggest that such changes may persist up to 2 years.
2 It appears
that successful therapeutic intervention at this stage could
have salvaged the tissue involved. Reversal of imaging changes
and clinical improvement after early intervention has been observed
in some reports.
1,2,4 Although an increase in antiepileptic
dosage was required, the lack of focal deficits despite an increase
in the interstitial edema and mass effect (
Fig 1D) may be due
to slow progression and also to the fact that the involved cortical
territory was relatively noneloquent. The unchanged neurologic
status at the chronic venous infarction stage supports the latter.
In addition, the other factors could be (1) a maintained delivery
of oxygenated blood as in venous sinus occlusive disease
2 resulting
in late as well as limited cell dysfunction/loss and (2) a reduced
or resolving venous hypertension due to evolution of the primary
lesion (ie, the DAVM). The localized involvement of parenchyma
in our case matches with the drainage territory of sphenoparietal
sinus and relates to the compromised venous drainage. Thus,
the affected parenchyma had little alternative venous drainage
available other than the sphenoparietal sinus affected by venous
hypertension leading to focal congestive encephalopathy.
In conclusion, the report highlights an unusual presentation in a case of cavernous sinus DAVM. It also draws attention to the entity of focal or localized chronic venous ischemia later evolving into venous infarction.
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References
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Received July 4, 2005;
accepted after revision July 25, 2005.
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Abstract
Introduction