CT angiogram findings in carotid-cavernous fistulas: stratification of imaging features to help radiologists avoid misdiagnosis

Abstract

<jats:sec><jats:title>Background</jats:title><jats:p> Carotid-cavernous fistulas (CCFs) are commonly misdiagnosed on computed tomography angiography (CTA). </jats:p></jats:sec><jats:sec><jats:title>Purpose</jats:title><jats:p> This study sought to identify the most sensitive and specific imaging features of CCFs on CTA. </jats:p></jats:sec><jats:sec><jats:title>Material and Methods</jats:title><jats:p> A retrospective review identified 18 consecutive patients suspected of having a CCF on CTA and subsequently underwent digital subtraction angiography (DSA). Two blinded reviewers assessed multiple findings on CTA: cavernous sinus asymmetry/enlargement; arterial-phase contrast in the cavernous sinus; proptosis; pre- or post-septal orbital edema; and dilated regional vasculature. Each was graded as positive, possible, and negative; “possible” was counted as positive. A third blinded reviewer served as a tiebreaker. </jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p> Of 18 patients, nine were true-positive and nine were false-positive. Superior ophthalmic vein early enhancement and dilatation had 100.0% sensitivity (95% confidence interval [CI] 40.0–100.0) and 77.8% specificity (95% CI 44.4–100.0); arterial-phase contrast in the cavernous sinus had 88.9% sensitivity (95% CI 44.4–100.0) and 66.7% specificity (95% CI 18.5–90.1); peri-orbital edema had 88.9% sensitivity (95% CI 35.5–100.0) and 77.8% specificity (95% CI 22.2–100.0). The most specific markers of CCF were superior petrosal sinus and inferior ophthalmic vein dilatation/enhancement (100.0%, 95% CI 88.8–100.0 and 88.9%, 95% CI 44.4–100.0, respectively); the specificity of asymmetric cavernous enlargement was 44.4% (95% CI 11.1–77.7). </jats:p></jats:sec><jats:sec><jats:title>Conclusions</jats:title><jats:p> Among patients in whom a CCF is suspected on CTA, superior ophthalmic vein dilatation/enhancement and arterial-phase contrast within the cavernous sinus are the most sensitive findings. Asymmetric cavernous sinus enlargement has poor specificity and may result in false-positive diagnoses of CCFs. False positive cases were less likely to have an optimally timed contrast bolus. </jats:p></jats:sec>

Correlation of Clinical Presentations and Imaging Findings with Flow Dynamics in Carotid-Cavernous Fistula Patients at Dr. Hasan Sadikin Hospital, Bandung

“…High cavernous pressure might be the cause of these imaging findings. This is in line with the study by Benson et al, [6] which also identified CS asymmetry and or hyperdensity at the affected site in the majority of patients. "Enlarged" CS was less commonly acknowledged among falsepositive than true-positive cases.…”

“…CCF often appears as an early enhancement of the CS on the side of the CCF, but not within the contralateral CS. Other imaging findings include dilatation of supraorbital vein, thickening of extraocular muscle, skull base fracture, and infarct [6].…”

Retrospective Cohort Study of Frequency and Patterns of Orbital Injuries on Whole-Body CT with Maxillofacial Multi-Slice CT

“…With an incidence of only 0.2%, CCF are very rare vasculopathies after trauma [31]. Nevertheless, their typical findings, a dilatation of the superior ophthalmic vein, as well as proptosis, enlarged cavernous sinus and extraocular muscles, and orbital edema should initiate further invasive diagnostics through cerebral angiography [12,14].…”

“…Even though MRI provides superior soft tissue contrast when compared to MSCT, and ultrasonography can survey the ocular globe precisely, MRI is less relevant in the acute setting due to long acquisition times as well as the possible risk of dislocation of metallic foreign bodies [10], and ultrasonography is contraindicated in cases of suspected globe rupture [11]. Nevertheless, contrast-enhanced MSCT can depict most soft tissue injuries accurately [12,13], and even hint to underlying carotid-cavernous fistulas (CCF) when dilated superior ophthalmic veins, exophthalmos, and orbital edema are present [14]. Furthermore, radiopaque intraorbital foreign bodies including glass fragments can be identified with a sensitivity of up to 90% on MSCT [2,15].…”

Clinical Profile and Management Outcomes among Patients with Carotid-Cavernous Fistula

“…Classification is based on etiology (spontaneous or traumatic), hemodynamic characteristics (high-or low-flow), and anatomic characteristics (direct or indirect). [1][2][3] Direct CCFs are high-flow shunts with direct connections between the ICA and the cavernous sinus. 4 Common causes include blunt trauma, ruptured ICA aneurysm, Ehlers-Danlos Syndrome, and iatrogenic interventions.…”