Download Thinking Outside the Intracranial Box

Thinking Outside
the Intracranial Box
A FAULKNER, P MEHTA, J GO
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No disclosures
Case
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53-year-old female with provided history of 6 month history of
progressive blurry vision in the right eye.
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Referred for time of flight (TOF) magnetic resonance angiogram
(MRA) of the head and neck and magnetic resonance imaging
(MRI) of the orbit.
Purpose
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Emphasize the importance of clinical history and relevance of
awareness of the patient's past medical and surgical history in
relation to image problem solving.
MRA demonstrates
prominent veins
within the left
temporal extraaxial space, as well
as flow related
signal within the
left transverse and
sigmoid sinus,
which raised the
possibility of a left
temporal dural
arteriovenous
fistula.
CT angiogram and venogram was performed which
demonstrated persistent prominence of the left
temporal cortical veins as well as prominent
venous drainage of the left pterygoid plexus and
enlargement of the foramen of Vesalius.
No obvious dural
arteriovenous fistula
was identified.
Symmetric contrast
enhancement of the
dural sinuses was
appreciated excluding
the possibility of dural
sinus venous
thrombosis
Conventional angiogram of the head confirmed the absence of a dural
arteriovenous fistula; however, absence of the typical visualization of the
dural sinuses during the early draining phase was noted. Instead,
prominent cortical veins again were seen, as well as prominent venous
drainage to the pterygoid plexus via an enlarged emissary vein.
Scout radiograph from
angiogram demonstrates
a left subclavian stent.
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Prior to the procedure the patient reported a history of resolved
renal failure requiring dialysis treatment via left arm
arteriorvenous fistula.
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Following the angiogram, post-procedure interrogation of the
patency of the arteriovenous fistula and subclavian stent with
ultrasound was performed.
Ultrasound of left upper extremity demonstrates
high arterialized flow of the AVF exacerbated by
subclavian venous stent stenosis with resultant
flow reversal of the left internal jugular vein
extending into the intracranial dural venous
sinuses
US images courtesy of Hischam Tchelpi
Comparison of the left (left) and right (right) internal jugular veins demonstrates low resistance
waveform with normal cardiac variation in the right internal jugular vein as opposed to high
resistance arterialized flow in the left internal jugular vein.
Color Doppler Ultrasound reveals arterialized, reversed flow
of the left internal jugular vein
Compression of the more distal arteriovenous fistula results in
subsequent normalization of left internal jugular venous flow.
Real time color Doppler images demonstrate unidirectional flow
of the left internal jugular vein and left common carotid artery.
Real time color Doppler images demonstrate normalization of
flow of the left internal jugular vein following compression of
the arteriovenous fistula.
Summary
Arterialization of the left arm dialysis arteriovenous fistula with
resultant venous flow reversal extending to the dural venous
sinuses mimicking a dural arterivenous fistula on MRA and CTA/CTV.
Summary

The importance of good clinical information such as the patient's
prior medical history must not be overlooked.
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In the setting of patients with known renal dysfunction and
arteriovenous fistula, consideration of their patency and distal
venous patency is warranted to avoid unnecessary testing and
delayed treatment of an extracranial problem.
References
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Lanzieri CF, Duchesneau PM, Rosenbloom SA, Smith AS,
Rosenbaum AE. The significance of asymmetry of the foramen of
Vesalius. AJNR Am J Neuroradio/1988;9:1201-1204
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Gandhi D. Intracranial dural arteriovenous fistulas: classification,
imaging findings, and treatment. AJNR Am J Neuroradiol. 2012
Jun;33(6):1007-13.
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Cognard C, Gobin YP, Pierot L et-al. Cerebral dural arteriovenous
fistulas: clinical and angiographic correlation with a revised
classification of venous drainage. Radiology. 1995;194 (3): 67180.