Clinical diagnosis
Case 311
【Progress】
After imaging diagnosis of brain MRI, she was introduced university hospital for management of CCF.
【Discussion】
Except traumatic injury, dura arterio-venous fistula (dura AVF) emerges predominantly in elderly woman after menopause with the ratio of woman versus man being 3:1 (1, 2). Although advanced dura AVF causes some disorders such as neural paralysis and hemorrhage, it is known that some dura AVFs spontaneously disappear or remain stable (2). Dura sinus accept blood flow from dura capillary flow and vaso-vasorum flow. The mechanism of emerging dura is not well-known but there is a thesis of forming dura AVF (2-5); first, partial dura sines occlusion occurs in a certain range; inducing regurgitation of dura venous flow to sinus and momentum of dilatation of capillary arterial flow and vaso-vasorum arterial flow. When partial recanalization of sinus leads to create a new shunt from arterial blood flow of dilated capillary artery and vaso-vasorum artery to regurgitated dura vein, called dura AVF (3-5).
Dura AVF most occurs on sigmoid sinus followed by cavernous sinus in western countries but in Japan on cavernous sins most followed by sigmoid sinus in Japan (2).
According to Borden classification, Dura AVF is classified into three types: type 1 AVF with normal venous blood flow (no vitalization of venous flow on angiography or CT angiography), type II AVF with regurgitation of blood flow to dura vein, type III AVF with sinus occlusion (5-7).
Carotid cavernous fistula is divided into two types; directly communication between carotid artery and cavernous sinus often emerged in traumatic injury: indirect communication between dilated meningeal branch artery or dilated vaso-varum artery from carotid artery and cavernous sinus often emerged spontaneously. Indirect CCF occurs in elderly woman after menopause which is reported to increase venous thromboembolism (VTE) risk (5-7).
The symptoms of CCF are diplopia, pulsatile exophthalmos, conjunctiva edema (chemosis) and/or hemorrhage, ptosis, cranial nerve palsy and subarachnoid hemorrhage and intracranial hemorrhage. Cranial nerves of III, IV, V and VI pass through cavernous sinus. Then, CCF can cause these nerve palsies although diplopia occurs most. Although sinus occlusion can cause bilateral venous infarction, CCF can cause subarachnoid hemorrhage and intracranial hemorrhage (2-5).
Our patient was a woman after menopause whose chief complaint was diplopia, and her brain MRI with time of flight depicted high signal intensity surrounding left internal carotid artery of C3 alongside Sella turcica and MRI with T1WI and T2WI depicted left superior ophthalmic vein. These findings are compatible with carotid cavernous fistula of type II. Especially, dilatation of superior ophthalmic vein was determinant for diagnosis of CCF.
【Summary】
We presented a sixty-five-year-old female for let consistent diplopia. Brain MRI Time of flight depicted a lesion with high signal intensity alongside with Sella turcica and dilated left superior ophthalmic vein, indicative of carotid cavernous fistula of type II. It is borne in mind that Time of Flight MRI was useful to detect CCF with high signal intensity alongside Sella turcica and both T1WI and T2WI showed marked dilatation of superior ophthalmic vein, determinately making a diagnosis of CSF. CSF is classified two types of direct AVF and indirect AVF. Indirect AVFCCF is reported to be formed by partial thrombosis of sinus, dilatation of capillary arteriole and arterial vaso-vasorum with regurgitation of draining vein, and then, associated with partial recanalization of thrombus, dilated arterial flow via capillary arteriole and arterial vaso-vasorum shunting to regurgitated draining vein, indicating that in case of CCF draining vein of ophthalmic vein is dilated.
【References】
1.Sato M, et al. Orbital Arteriovenous Fistula around the Optic Nerve Treated by Transvenous Embolization. Turk Neurosurg. 2019;29(2):303-305.
2.Tsumoto T, et al. Cavernous Sinus Dural Arteriovenous Fistulas: General Aspects. Journal of Neuroendovascular Therapy 2020; 14: 565–571
3.Davies MA,et-al. The natural history and management of intracranial dural arteriovenous fistulae. Part 2: aggressive lesions. Interv Neuroradiol. 2012;3 (4): 303-11.
4.Cognard C, et-al. Cerebral dural arteriovenous fistulas: clinical and angiographic correlation with a revised classification of venous drainage. Radiology. 1995;194 (3): 671-80.
5.Gandhi D, et-al. Intracranial dural arteriovenous fistulas: classification, imaging findings, and treatment. AJNR Am J Neuroradiol. 2012;33 (6): 1007-13
6.Lee SK, et-al. MR imaging of dural arteriovenous fistulas draining into cerebellar cortical veins. AJNR Am J Neuroradiol. 2003;24 (8): 1602-6.
7.Willinsky R, et-al. Tortuous, engorged pial veins in intracranial dural arteriovenous fistulas: correlations with presentation, location, and MR findings in 122 patients. AJNR Am J Neuroradiol. 20 (6): 1031-6.
2023.9.22