Anatomic variations of the deep cerebral veins,tributaries of Basal vein of rosenthal: embryologic aspects of the regressed embryonic tentorial sinus

Abstract

The embryonic tentorial sinus regresses at the 60-80 mm embryologic stage and most of the deep venous channels constitute the basal vein of Rosenthal (BVR). Persisting remnants of the embryonic tentorial sinus can be seen in the adult configuration of the BVR.We tried to explain the anatomic representations of the BVR associated with the remnant embryonic tentorial sinus. A total 41 patients and 82 hemispheres were included in this study. CT angiography was performed in all patients as screening for cerebrovascular disease or other intracranial disorders. A separate workstation and 3D software were used to evaluate the cranial deep venous systems with 3D volume rendering techniques, thin-slice MIP images, and MPR techniques for the analysis of complicated angioarchitecture. Variations of the BVR were classified according to the developmental alterations of efferent pathways into four groups: telencephalic group (A) including tributaries of the uncal vein, inferior frontal vein, anterior communicating vein, and inferior striatal vein; diencephalic group (B) of the interior ventricular vein and peduncular vein; tegmental bridging group (C) of the longitudinal LMV anastomosis; tectal group (D) of the superior vermian vein and internal occipital vein in relation to the Galenic connection. The BVR constituted from the embryonic tentorial sinus was also assessed and the developmental aspects reviewed. Remnant embryonic tentorial sinus was visualized in 12% (10/82) of hemispheres, all of them invariably connected with the telencephalic (A) and diencephalic (B) groups. Most of those connections (9/10) to basal venous tributaries originated from the medial tentorial sinus except one case from the lateral tentorial sinus. No Galenic connections of the BVR were identified in 10% (8/82). Various tributaries of the BVR were classified as: Telencephalic group (A) 43% (35/82), Diencephalic group (B) 35% (29/82), Bridging group (C) 11% (9/82), and Tectal group (D) 6% (5/82). Four cases (5%) were unclassified and revealed only small basal tributaries of the BVR without connection to the great vein of Galen. Anatomic variations of the BVR connected with persistent embryonic tentorial sinus could often be demonstrated in adult configurations considering the embryologic aspects of developmental regression and secondary cerebral venous adaptations.

Figure 1

Classifications of the Basal vein of Rosenthal (BVR) according to the developmental alterations of efferent pathways:A) Telencephalic group, including tributaries of the inferior striatal vein, uncal vein, inferior frontal vein, anterior communicating vein,deep middle cerebral vein (arrows).B) Diencephalic group,including tributaries of the peduncular vein,inferior ventricular vein (arrows), posterior communicating vein. C) Tegmental bridging group of lateromesencephalic vein (LMV) anastomosis (arrows) with superior petrosal sinus. D) Tectal group of superior vermian vein. This figure shows the Galenic connection of the small BVR constituting the superior vermian vein (short arrows) and adjacent posterosuperior cerebellar vein (long arrows). 1, basal vein of Rosenthal (BVR); 2, vein of Galen; 3, deep middle cerebral vein (DMCV); 4, inferior striatal vein; 5, inferior ventricular vein; 6, superior petrosal sinus; 7, choroid plexus.

Figure 2

Patterns of the remnant embryonic tentorial sinus constituting the BVR. A) Medial tentorial sinus (arrows) towards the telencephalic group. B) Bilateral tentorial sinuses (arrows) toward the telencephalic group. C) Medial tentorial sinus (arrows) towards the diencephalic group. D) Lateral tentorial sinus (arrows) towards the telencephalic group. E) Medial tentorial sinus (arrows) towards the diencephalic group, inferior ventricular and interpeduncular vein. F) Medial tentorial sinus (arrows) terminates into the straight sinus, viewed from the lateral direction. 1, basal vein of Rosenthal (BVR); 2, vein of Galen; 3, deep middle cerebral vein (DMCV); 4, inferior ventricular vein; 5, interpeduncular vein; 6, internal cerebral vein; 7, straight sinus; 8, torcular; 9, transverse sinus; 10, straight sinus.

Figure 2

Patterns of the remnant embryonic tentorial sinus constituting the BVR. A) Medial tentorial sinus (arrows) towards the telencephalic group. B) Bilateral tentorial sinuses (arrows) toward the telencephalic group. C) Medial tentorial sinus (arrows) towards the diencephalic group. D) Lateral tentorial sinus (arrows) towards the telencephalic group. E) Medial tentorial sinus (arrows) towards the diencephalic group, inferior ventricular and interpeduncular vein. F) Medial tentorial sinus (arrows) terminates into the straight sinus, viewed from the lateral direction. 1, basal vein of Rosenthal (BVR); 2, vein of Galen; 3, deep middle cerebral vein (DMCV); 4, inferior ventricular vein; 5, interpeduncular vein; 6, internal cerebral vein; 7, straight sinus; 8, torcular; 9, transverse sinus; 10, straight sinus.

Figure 3

Embryologic draining (anastomotic) patterns between the BVR and remnant embryonic tentorial sinus according to each stage of development by Padget DH. A) Stage 6, 22-24 mm stage. Primarily the ventral diencephalic veins, supplemented by the primitive internal cerebral vein, drain the conspicuous choroid plexus of the lateral ventricle. B) Stage 7a, 60-80 mm stage. The internal cerebral vein is still primitive and constitutes the drainage of the large superior choroid vein into the straight sinus. The basal cerebral vein is formed by longitudinal anastomoses between several primitive pial veins, the deep middle cerebral, the ventral or dorsal diencephalic veins, the mesencephalic vein, and a tributary of the primitive straight sinus. C) Infant or adult stage. A lateral mesencephalic vein (LMV; arrows) anastomosing the basal veins with the ventral metencephalic veins sometimes become the only outlet of the basal veins. 1,superior choroidal vein;2,primitive internal cerebral vein; 3, primitive BVR; 4, ventral diencephalic vein; 5, mesencephalic vein, 6, embryonic tentorial sinus; 7, straight sinus; 8, marginal sinus (primitive transverse sinus); 9, tentorial plexus; 10, vein of Galen; 11, superior petrosal sinus (great anterior cerebellar vein); 12, inferior ventricular vein.