Supratentorial Dural Venous Channel (SDVC): Imaging Anatomy Evaluated on CT Venography.

Objective: A rare anatomical pattern exists in which a cortical vein courses vertically while running parallel to the supratentorial dura mater, enters the dura, and ultimately drains into the transverse sinus (TS). This structure is referred to as the supratentorial dural venous channel (SDVC). In this study, we retrospectively reviewed the imaging characteristics of SDVCs. Methods: We consecutively included patients with brain tumors, ischemic disease, or vascular malformations who underwent CT venography (CTV) between January 2020 and October 2023. During the study period, CTV was performed in 223 patients (454 sides) using standardized protocols designed to detect SDVCs (97 males and 126 females; mean age, 55.9 years; range, 0-87 years). Results: SDVCs were identified in 15 sides (3.3%) among 454 evaluated sides. As the SDVC enters the dura mater, continuity of the vessel often becomes indistinct; however, after the transition, the vein typically appears flattened. The draining cortical veins were classified into 4 types: the vein of Labbé (73%), the posterior temporal vein (27%), the occipital vein (27%), and the anterior temporal vein (13%). Sixty-seven percent of SDVCs drained into the lateral half of the TS, whereas 33% drained into the medial half. A characteristic notch on the inner table of the skull was observed at the dural entry point in 93% of cases. Conclusion: The SDVC represents an important anatomical structure that should be carefully evaluated during craniotomy or endovascular procedures, and it can be reliably identified on CTV. The combination of transient venous indistinctness and inner table notching represents characteristic findings corresponding to the dura mater entry site.