Tentorial Venous Anatomy: Variation in the Healthy Population

Abstract

BACKGROUND AND PURPOSE: A new transtentorial venous system consisting of medial, intermediate, and lateral tentorial veins, connecting infra-and supratentorial compartments, was recently shown in 2 cadaver dissections and 2 patient scans. We sought to characterize the venous patterns within the tentorium and their relation to measures of skull development in a cohort of healthy adults. MATERIALS AND METHODS: We retrospectively reviewed tentorial venous anatomy of the head using CTA/CTV performed for routine care or research purposes in 238 patients. Included studies had adequate contrast opacification of venous structures and a section thickness of #2 mm; we excluded cases with space-occupying lesions and vascular pathologies. Tentorial angle, dural sinus configurations, and measures of skull base development were assessed as predictors of tentorial venous anatomy variation via Cramér V association, the binary encoded Pearson correlation, and nearest-point algorithm with the Euclidean distance metric for clustering. RESULTS: Tentorial vein development was related to the ringed configuration of the tentorial sinuses (P , .005). There were 3 configurations. Groups 1A and 1B (n ¼ 50/238) had ringed configuration, while group 2 did not (n ¼ 188/238). Group 1A (n ¼ 38/50) had a medialized ringed configuration, and group 1B had a lateralized ringed configuration (n ¼ 12/50). Measurements of skull base development were predictive of these groups. The ringed configuration of group 1 was related to the presence of a split confluens, which correlated with a decreased internal auditory canal-petroclival fissure angle. Configuration 1A was related to the degree of petrous apex pneumatization (P value ¼ .010). CONCLUSIONS: Variations in the transtentorial venous system directly correlate with cranial development. ABBREVIATIONS: CC-JB ¼ carotid canal-jugular bulb; IAC-PCF ¼ internal auditory canal-petroclival fissure; ITV ¼ intermediate tentorial vein; LTS ¼ lateral tentorial sinus; LTV ¼ lateral tentorial vein; MTS ¼ medial tentorial sinus; MTV ¼ medial tentorial vein; RC ¼ ringed configuration

Tentorial venous anatomy of mice and humans

“…This dilation leads to out-pouching of these structures into the tentorium, which we believe may also lead to the development of the MTS and LTS. Our study was the first to report a consistent TTVS in adult humans (1,2). In contrast to what has previously been reported, we believe tentorial venous drainage persists, rather than regresses, when jugular venous drainage becomes dominant.…”

“…Further, in this study, we demonstrate how the embryologic dorsal tentorial venous plexus transitions to this adult configuration in the post-natal period. Our findings in these studies suggest that these veins, previously thought to obliterate during tentorial development based on previous human developmental studies, remain patent in the adult as continuous venous drainage between the anterior, middle, and posterior fossae (1)(2)(3)(4).…”

“…Reconstruction was carried out with a modified Feldkampii algorithm using the SkyScan TM NRecon software accelerated by GPU. Gaussian smoothing, ring artifact reduction, and beam hardening correction were applied (1,2). MRI of gadolinium-immersed mice was performed with a 14T ex vivo tissue scanner.…”

“…Our recent discovery of the TTVS warrants reevaluation of our understanding of the development of the intracranial venous system. We hypothesized that this TTVS, which we described in a large study of healthy human adults, is the adult derivative of the embryologic tentorial plexus (1,2). We found this system in humans to be comprised of three dominant veins with plexiform anastomoses as follows.…”

“…We previously identified a consistent transtentorial venous system (TTVS) in humans that connects venous drainage throughout the brain and proposed its relationship to neurosurgical outcomes, including postoperative remote cerebellar infarct ( 1 , 2 ). These often-fatal clinical outcomes highlight the need to understand the complete intracranial vascular network.…”