An anatomy-based lumped parameter model of cerebrospinal venous circulation: can an extracranial anatomical change impact intracranial hemodynamics?

Abstract

BackgroundThe relationship between extracranial venous system abnormalities and central nervous system disorders has been recently theorized. In this paper we delve into this hypothesis by modeling the venous drainage in brain and spinal column areas and simulating the intracranial flow changes due to extracranial morphological stenoses.MethodsA lumped parameter model of the cerebro-spinal venous drainage was created based on anatomical knowledge and vessels diameters and lengths taken from literature. Each vein was modeled as a hydraulic resistance, calculated through Poiseuille’s law. The inputs of the model were arterial flow rates of the intracranial, vertebral and lumbar districts. The effects of the obstruction of the main venous outflows were simulated. A database comprising 112 Multiple Sclerosis patients (Male/Female = 42/70; median age ± standard deviation = 43.7 ± 10.5 years) was retrospectively analyzed.ResultsThe flow rate of the main veins estimated with the model was similar to the measures of 21 healthy controls (Male/Female = 10/11; mean age ± standard deviation = 31 ± 11 years), obtained with a 1.5 T Magnetic Resonance scanner. The intracranial reflux topography predicted with the model in cases of internal jugular vein diameter reduction was similar to those observed in the patients with internal jugular vein obstacles.ConclusionsThe proposed model can predict physiological and pathological behaviors with good fidelity. Despite the simplifications introduced in cerebrospinal venous circulation modeling, the key anatomical feature of the lumped parameter model allowed for a detailed analysis of the consequences of extracranial venous impairments on intracranial pressure and hemodynamics.Electronic supplementary materialThe online version of this article (doi:10.1186/s12883-015-0352-y) contains supplementary material, which is available to authorized users.

Intracranial volumetric changes govern cerebrospinal fluid flow in the Aqueduct of Sylvius in healthy adults

“…More recently, other researchers have developed these ideas to produce complex lumped parameter models to simulate: jugular venous waveforms [42]; the hydrodynamics of the cerebrospinal system [10]; and the CSF flow dynamics associated with syringomyelia [43]. Finally, Marcotti et al [44] used an anatomy-based lumped parameter model to simulate the effect of IJV constriction on intracranial haemodynamics and ICP.…”

“…It has also been shown to increase in the amplitude of the aCSF pulse [1,2], suggesting that an over-accumulation of blood in the cortical veins in some way alters the dynamics of the aqueductal CSF pulse. While the mechanics associated with this are not fully understood, constriction of the IJVs will tend increase the venous blood pressure in the superior sagittal sinus, resulting in reduced CSF absorption [44,59], something that might affect the aCSF pulse. In addition, as the cortical veins expand in diastole, the overall volume of the SAS will decrease, with the result that the compliance and hydraulic resistance of this space will change.…”

Assessment of Internal Jugular Vein Size in Healthy Subjects with Magnetic Resonance and Semiautomatic Processing

“…In the context of combined studies on neurodegeneration and vascular alterations, the proposed IJV segmentation method can provide reproducible IJV CSA measures that can be used to assess the correlation with clinical or MRI-derived neurodegenerative indices. Indeed, as we showed by modeling the cerebrospinal venous system and by simulating progressive IJV stenoses [ 21 ], an IJV patency decrement theoretically increases the intracranial pressure and thus could lead to neurodegenerative effects. Furthermore, the proposed normalization approach can be used for case-control studies.…”

Validation of a Hemodynamic Model for the Study of the Cerebral Venous Outflow System Using MR Imaging and Echo-Color Doppler Data

“…Several researchers have studied the cerebral hemodynamics and its relationship with extracranial anatomic and posture changes. 27,28 First, average absolute values of blood flow could be considerably different among subjects because of physiologic variability. Second, due to the complex network of vessels and their variable interconnections, it is difficult to have a map of the circulation able to describe any specific case in detail.…”