A venous mechanism of ventriculomegaly shared between traumatic brain injury and normal ageing

Abstract

Recently, age-related timing dissociation between the superficial and deep venous systems has been observed; this was particularly pronounced in patients with normal pressure hydrocephalus, suggesting a common mechanism of ventriculomegaly. Establishing the relationship between venous drainage and ventricular enlargement would be clinically relevant and could provide insight into the mechanisms underlying brain ageing. To investigate a possible link between venous drainage and ventriculomegaly in both normal ageing and pathological conditions, we compared 225 healthy subjects (137 males and 88 females) and 71 traumatic brain injury patients of varying ages (53 males and 18 females) using MRI-based volumetry and a novel perfusion-timing analysis. Volumetry, focusing on the CSF space, revealed that the sulcal space and ventricular size presented different lifespan profiles with age; the latter presented a quadratic, rather than linear, pattern of increase. The venous timing shift slightly preceded this change, supporting a role for venous drainage in ventriculomegaly. In traumatic brain injury, a small but significant disease effect, similar to idiopathic normal pressure hydrocephalus, was found in venous timing, but it tended to decrease with age at injury, suggesting an overlapping mechanism with normal ageing. Structural bias due to, or a direct causative role of ventriculomegaly was unlikely to play a dominant role, because of the low correlation between venous timing and ventricular size after adjustment for age in both patients and controls. Since post-traumatic hydrocephalus can be asymptomatic and occasionally overlooked, the observation suggested a link between venous drainage and CSF accumulation. Thus, hydrocephalus, involving venous insufficiency, may be a part of normal ageing, can be detected non-invasively, and is potentially treatable. Further investigation into the clinical application of this new marker of venous function is therefore warranted.

Brain aging mechanisms with mechanical manifestations

“…Aso et al have investigated a possible link between venous drainage and ventricular enlargement in both normal and accelerated aging ( Aso et al, 2020 ). They found that changes encountered in cerebral venous drainage stems from venous insufficiency occur in normal aging processes.…”

“…They found that changes encountered in cerebral venous drainage stems from venous insufficiency occur in normal aging processes. They motivate ventricular enlargement to result from this change in the venous drainage pattern as well as cerebral atrophy ( Aso et al, 2020 ). This agrees with work by Apostolova et al that link ventricular enlargement to parenchymal volume loss following the progressive loss of neurons and de-arborization of the dendritic network ( Apostolova et al, 2012 ).…”

White Matter Microstructural Damage Associated With Gait Abnormalities in Idiopathic Normal Pressure Hydrocephalus

“…For example, compared with healthy controls, patients with iNPH showed increased FA, MD, and AD in the periventricular section of the CST (Hattingen et al, 2010 ; Hattori et al, 2012 ; Saito et al, 2020 ); decreased FA; and increased RD in the upper section of the CST and corpus callosum (Kanno et al, 2011 ; Saito et al, 2020 ), which may result from the mechanical force exerted by the abnormal ventriculomegaly on the surrounding tissues. Aso et al suggested that one of the mechanisms of ventricular enlargement is that changes in the venous drainage pattern could result in CSF absorption disorder in patients with iNPH (Aso et al, 2020 ). Kamiya et al ( 2017 ) reported an increased orientational coherence at the CST in patients with iNPH after CSF shunt surgery, which supports the oppression of periventricular tissue.…”

Brain Shape Changes Associated With Cerebral Atrophy in Healthy Aging and Alzheimer’s Disease

“…Ventricular enlargement is accompanied by an increase in the space between folds and loss of gyrification (Hamelin et al, 2015;Aso et al, 2020). This feature is less prominent on medical images, but is another indicator for the significant topological changes of the brain (Plocharski et al, 2016;Shen et al, 2018).…”