[Detection of the venous system of the skull base using three-dimensional CT angiography (3D-CTA): utility of the subtemporal approach].

Three-dimensional computed tomography angiography (3D-CTA) was compared with digital subtraction angiography (DSA) for the delineation of the skull base venous system in presurgical planning of the subtemporal approach in 201 sides of 109 patients. The axial stereoscopic images and multi-projection images were used in 3D-CTA, and the anteroposterior views and lateral views were used in DSA. DSA showed that the vein of Labbe (VL) was the most common venous flow on the lateral or basal surface of the temporal lobe, whereas 3D-CTA demonstrated that the involvement of the temporo-basal vein (TBV) was equal to that of VL in frequency. 3D-CTA showed that the VL flowed into the transverse sinus (TS) on 132 sides, the sigmoid sinus-TS junction on 29 sides, and the lateral tentorial sinus (LTS) on 40 sides. DSA showed that the VL flowed into the TS on 157 sides and into the LTS only on 5 sides. DSA showed that the TBV flowed into the TS on 37 sides but axial 3D-CTA showed that the TBV flowed into the LTS on 48 sides. This inconsistency reflects the difficulty in confirming and identifying these veins on the anteroposterior view of DSA, due to the overlapping of veins and poor delineation. Axial stereo and multi-projection images of 3D-CTA provided practical images of the deep veins of the skull base venous system and showed the relative anatomical relationships of the arteries and bony structures. This information can specify the venous inflow point, and help to determine the direction of approach and working space, and also help to identify intraoperative landmarks for the subtemporal approach. Presurgical examination of the deep venous system with 3D-CTA may help to minimize unexpected injury to veins and venous infarction.