Thin-Section MR Imaging for Carotid Cavernous Fistula

Abstract

Background and purpose: Carotid-cavernous fistulas are abnormal vascular shunts that can cause various neurologic or orbital symptoms. The purpose of this retrospective study was to evaluate the diagnostic performance of thin-section MR imaging for carotid cavernous fistula in patients with clinically suspected carotid cavernous fistula, and to identify possible imaging predictors of carotid cavernous fistula.

Materials and methods: A total of 98 patients who were clinically suspected of having carotid cavernous fistula (according to their symptoms and physical examinations) between January 2006 and September 2018 were included in this study. The patients underwent pretreatment thin-section MR imaging and DSA. Thin-section MR imaging consisted of 2D coronal T1- and T2WI with 3-mm thickness and 3D contrast-enhanced T1WI with 0.6 mm thickness. The diagnostic performance of thin-section MR imaging for carotid cavernous fistula was evaluated with the reference standard of DSA. Univariate logistic regression analysis was performed to determine possible imaging predictors of carotid cavernous fistula.

Results: Among the 98 patients, DSA confirmed 38 as having carotid cavernous fistula. The overall accuracy, sensitivity, and specificity of thin-section MR imaging were 88.8%, 97.4%, and 83.3%, respectively. Possible imaging predictors on thin-section MR imaging included abnormal contour of the cavernous sinus (OR: 21.7), internal signal void of the cavernous sinus (OR: 15.3), prominent venous drainage flow (OR: 54.0), and orbital/periorbital soft tissue swelling (OR: 40.4).

Conclusions: Thin-section MR imaging provides high diagnostic performance and possible imaging predictors of carotid cavernous fistula in patients with clinically suspected carotid cavernous fistula. Thin-section MR imaging protocols could help decide appropriate management plans for patients with clinically suspected carotid cavernous fistula.

FIG 1.

Flow diagram of the case selection procedure and case numbers in each subgroup.

FIG 2.

A CCF case with abnormal contour of the cavernous sinus. Coronal T2-weighted image of a patient with diplopia, confirmed to be left sixth cranial nerve palsy on neurologic examination. Note the abnormal contour bulging of the left cavernous sinus (arrow). An internal signal void was also noted on both T2-weighted (arrow) and T1-weighted imaging (not shown). The patient was confirmed as having a direct CCF on digital subtraction angiography.

FIG 3.

A CCF case with internal signal void of the cavernous sinuses. Coronal T1-weighted image of a patient with diplopia, confirmed to be right third cranial nerve palsy on neurologic examination. Note the internal signal void in both cavernous sinuses visible on T1-weighted image (arrows). The patient was confirmed to have an indirect CCF on digital subtraction angiography.

FIG 4.

A CCF case with prominent venous drainage flow in the anterior and lateral venous structures. Axial contrast-enhanced T1-weighted image of a patient with right ocular pain and conjunctival injection. Note the enlarged right superior ophthalmic vein (anterior; arrow) and right sphenoparietal sinus (lateral; arrowhead). The patient was confirmed as having an indirect CCF on digital subtraction angiography.

FIG 5.

A CCF case with prominent venous drainage flow in the posterior venous structure. Axial contrast-enhanced T1-weighted image of a patient with diplopia, confirmed to be right sixth cranial nerve palsy on neurologic examination. Note the enlarged right inferior petrosal sinus (posterior) with an internal signal void (arrow) indicating increased flow rate. The patient was confirmed as having an indirect CCF on digital subtraction angiography.

FIG 6.

A CCF case with high signal change and orbital soft tissue thickening. Coronal T2-weighted image of a patient with periorbital swelling, conjunctival injection, ocular pain, and diplopia. Fat stranding and swelling of extraocular muscles (arrow) are noted. Prominent venous drainage flow in the superior ophthalmic vein is also noted (arrowhead). The patient was confirmed as having an indirect CCF on digital subtraction angiography.