RT Journal Article SR Electronic T1 E-034 High-resolution contrast-enhanced cone beam CT in planning of endovascular treatment for complex dural arteriovenous fistulae JF Journal of NeuroInterventional Surgery JO J NeuroIntervent Surg FD BMJ Publishing Group Ltd. SP A44 OP A45 DO 10.1136/neurintsurg-2020-SNIS.70 VO 12 IS Suppl 1 A1 Orru, E A1 Marosfoi, M A1 Patel, N A1 Wakhloo, A YR 2020 UL http://jnis.bmj.com/content/12/Suppl_1/A44.3.abstract AB Purpose Treatment of dural arteriovenous fistulae (DAVFs) is based on obliteration of the fistula via trans-arterial/trans-venous approaches or a combination thereof. In complex cases it can be difficult to determine the fistulous point, and large segments of normal vascular structures are sacrificed to cure the fistulae. High-resolution intraoperative contrast-enhanced cone beam CT (CE-CBCT) allows visualization of arteriovenous vascular structures and their relationship with bony structures and the dura. We present 2 cases of complex DAVFs in which CE-CBCT, by clearly showing the fistulous point, allowed a targeted treatment that avoided unnecessary venous sacrifice and maintained/restored functionality of normal venous structures.Materials and Methods In two patients who presented with complex DAVFs, DSA was insufficient in clarifying the anatomy of the shunt. CE-CBCT was obtained on a last generation biplane Neuroangiography system infusing a 69 mL bolus (30% Visipaque 270) at a rate of 3 mL/second into the main arterial feeder (22 cm FOV; 23 second 200-degree rotation). High-resolution volumetric data generated was reconstructed using an FBP algorithm and post-processed on a dedicated workstation for final treatment strategy.Results A 90-year-old man with progressively slurred speech, had a petrosal/tentorial Cognard 4 DAVF fed by multiple left ECA feeders. CE-CBCT demonstrated an enlarged draining petrosal dural venous pouch draining in the basal vein of Rosenthal. Access route to the pouch was planned on CE-CBCT reconstructions (Image A, dotted line), allowing selective occlusion with coils and Onyx with complete resolution of the DAVF and preservation of normal deep venous structures. The patient’s symptoms resolved shortly following the procedure.The second subject, a 49-year-old man presented with debilitating right-sided pulsatile tinnitus, blurred vision and headaches. A DSA demonstrated a complex, Cognard 1 fistula of the right sigmoid sinus with innumerable external carotid artery (ECA) feeders and loss of drainage functionality of the right transverse-sigmoid sinus. CE-CBCT showed feeders converging in a dural venous pouch adjacent to the postero-lateral wall of the sigmoid sinus (Image B, stars). Similarly to prior case, a CE-CBCT-planned microcathetarization was performed with targeted obliteration of the pouch with coils and Onyx followed by DAVF resolution and restoration of normal antegrade venous flow. Tinnitus resolved, but blurred vision and headaches persisted. Venous pressure measurements demonstrated a 10-mmHg gradient across the narrowed sigmoid sinus. Venous stenting led to complete symptom resolution.Abstract E-034 Figure 1 Conclusion High-resolution CE-CBCT allows identification of fistulous connections in complex DAVFs and supports an accurate and minimally-deconstructive treatment with sparing of normal venous structures.Disclosures E. Orru: None. M. Marosfoi: None. N. Patel: None. A. Wakhloo: None.