The Design of a Digital Cerebrovascular Simulation Model for Teaching and Research

Giannessi, Massimo; Ursino, Mauro; Murray, W. Bosseau

doi:10.1213/ane.0b013e318187b987

Cited by 9 publications

(6 citation statements)

References 21 publications

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“…The mathematical model of the cerebral hemodynamics, enclosed in the "BRAIN" dashed rectangle of Fig. 1, has been fully developed and validated by Ursino and colleagues in previous works (13,30,32). This model simulates the hemodynamics of the arterial-arteriolar and venous cerebrovascular bed, the cerebral arterioles regulation mechanisms, the cerebrospinal fluid production and reabsorption processes, the Starling resistor mechanism for the cerebral veins, and the nonlinear pressure-volume relationship of the craniospinal compartment.…”

Section: Model Descriptionmentioning

confidence: 99%

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A new hemodynamic model for the study of cerebral venous outflow

Gadda

Taibi

Sisini

et al. 2015

American Journal of Physiology-Heart and Circulatory Physiology

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We developed a mathematical model of the cerebral venous outflow for the simulation of the average blood flows and pressures in the main drainage vessels of the brain. The main features of the model are that it includes a validated model for the simulation of the intracranial circulation and it accounts for the dependence of the hydraulic properties of the jugular veins with respect to the gravity field, which makes it an useful tool for the study of the correlations between extracranial blood redistributions and changes in the intracranial environment. The model is able to simulate the average pressures and flows in different points of the jugular ducts, taking into account the amount of blood coming from the anastomotic connections; simulate how the blood redistribution due to change of posture affects flows and pressures in specific points of the system; and simulate redistributions due to stenotic patterns. Sensitivity analysis to check the robustness of the model was performed. The model reproduces average physiologic behavior of the jugular, vertebral, and cerebral ducts in terms of pressures and flows. In fact, jugular flow drops from ϳ11.7 to ϳ1.4 ml/s in the passage from supine to standing. At the same time, vertebral flow increases from 0.8 to 3.4 ml/s, while cerebral blood flow, venous sinuses pressure, and intracranial pressure are constant around the average value of 12.5 ml/s, 6 mmHg, and 10 mmHg, respectively. All these values are in agreement with literature data. mathematical modeling; cerebral outflow; posture dependence; jugular veins collapse; collateral routes THE EXTRACRANIAL VENOUS SYSTEM represents an important determinant of the brain circulation, but its role in the pathology of the central nervous system is not fully understood yet (4,26). It is recognized that, in supine position, the jugular veins represent the main outflow route for the cerebral circulation (2,6,25,36,38), being able to carry most of blood flow from the brain and from other extracerebral territories (ϳ700 -720 ml/ min; Refs. 27, 33) with respect to a cerebral blood inflow of ϳ750 ml/min (45). However, the jugular venous system exhibits important flow limitation during upright posture changes, because the jugular veins tend to collapse as a consequence of the decrease of transmural pressure due to the gravitational field, causing a significant increase in resistance (3,7,12,14,26). In the absence of other routes for extracranial outflow, this flow limitation would have dramatic effects on the cerebral circulation, since, apart from brief transient time intervals, the average cranial arterial inflow is expected to be equal to the cranial venous outflow for the mass preservation.As a consequence, large attention has been devoted to the venous circulation in the upright state, in an effort to understand which alternative routes can carry the brain venous outflow. It has long been postulated that the vertebral venous system may provide an important alternative route for venous outflow when standing or sitting; this was f...

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Section: Model Descriptionmentioning

confidence: 99%

“…1) An accurate model of the intracranial circulation developed in past years, which incorporates the autoregulation of cerebral blood flow (13,30,32). This model provides the correct values of cerebral blood flow to the venous return model.…”

mentioning

confidence: 99%

A new hemodynamic model for the study of cerebral venous outflow

Gadda

Taibi

Sisini

et al. 2015

American Journal of Physiology-Heart and Circulatory Physiology

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“…23,74 It differentiates among the different vascular districts perfused by the six cerebral arteries and incorporates the Circle of Willis as well distal cortical anastomoses among the districts.…”

Section: Mathematical Model: Qualitative Descriptionmentioning

confidence: 99%

“…With that model, we were able to simulate cerebral hemodynamics and ICP dynamics and their alterations in head injured patients (including the genesis of plateau waves, 23,74 and the effect of head up position 23 ). Furthermore, via a best-fitting estimation of a few parameters, the model was able to simulate the time pattern of ICP and blood flow velocity in the middle cerebral artery (MCA) in head injured patients during pressure-volume tests, 74 and following CO 2 and mean systemic arterial pressure (MAP) changes.…”

Section: Introductionmentioning

confidence: 99%

A Model of Cerebrovascular Reactivity Including the Circle of Willis and Cortical Anastomoses

Ursino

Giannessi

2010

Ann Biomed Eng

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Cerebrovascular pathologies are extremely complex, due to the multitude of factors acting simultaneously on cerebral hemodynamics. In this work, a mathematical model of cerebral hemodynamics and intracranial pressure (ICP) dynamics, developed in previous years, is extended to account for heterogeneity in cerebral blood flow. The model includes the Circle of Willis, six regional districts independently regulated by autoregulation and CO2 reactivity, distal cortical anastomoses, venous circulation, the cerebrospinal fluid circulation, and the ICP-volume relationship. Results agree with data in the literature and highlight the existence of a monotonic relationship between transient hyperemic response and the autoregulation gain. During unilateral internal carotid artery stenosis, local blood flow regulation is progressively lost in the ipsilateral territory with the presence of a steal phenomenon, while the anterior communicating artery plays the major role to redistribute the available blood flow. Conversely, distal collateral circulation plays a major role during unilateral occlusion of the middle cerebral artery. In conclusion, the model is able to reproduce several different pathological conditions characterized by heterogeneity in cerebrovascular hemodynamics and cannot only explain generalized results in terms of physiological mechanisms involved, but also, by individualizing parameters, may represent a valuable tool to help with difficult clinical decisions.

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“…Scientific effort has been made to reproduce, using mathematical modeling, adaptive phenomena such as the short-term responses of the coronary circulation to physiological changes following exercise, 10 or cerebro-vascular regulation mechanisms in response to external and pathological perturbations. 7 Nevertheless, to the best of our knowledge, mid/long-term adaptive phenomena have not been considered in patient-specific models for pre-operative planning.…”

Section: Discussionmentioning

confidence: 99%

Integration of Clinical Data Collected at Different Times for Virtual Surgery in Single Ventricle Patients: A Case Study

Corsini¹,

Baker²,

Baretta³

et al. 2014

Ann Biomed Eng

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Newborns with single ventricle physiology are usually palliated with a multi-staged procedure. When cardiovascular complications e.g., collateral vessel formation occur during the inter-stage periods, further treatments are required. An 8-month-old patient, who underwent second stage (i.e., bi-directional Glenn, BDG) surgery at 4 months, was diagnosed with a major veno-venous collateral vessel (VVC) which was endovascularly occluded to improve blood oxygen saturations. Few clinical data were collected at 8 months, whereas at 4 months a more detailed data set was available. The aim of this study is threefold: (i) to show how to build a patient-specific model describing the hemodynamics in the presence of VVC, using patient-specific clinical data collected at different times; (ii) to use this model to perform virtual VVC occlusion for quantitative hemodynamics prediction; and (iii) to compare predicted hemodynamics with post-operative measurements. The three-dimensional BDG geometry, resulting from the virtual surgery on the first stage model, was coupled with a lumped parameter model (LPM) of the 8-month patient's circulation. The latter was developed by scaling the 4-month LPM to account for changes in vascular impedances due to growth and adaptation. After virtual VVC closure, the model confirmed the 2 mmHg BDG pressure increase, as clinically observed, suggesting the importance of modeling vascular adaptation following the BDG procedure.

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The Design of a Digital Cerebrovascular Simulation Model for Teaching and Research

Cited by 9 publications

References 21 publications

A new hemodynamic model for the study of cerebral venous outflow

A new hemodynamic model for the study of cerebral venous outflow

A Model of Cerebrovascular Reactivity Including the Circle of Willis and Cortical Anastomoses

Integration of Clinical Data Collected at Different Times for Virtual Surgery in Single Ventricle Patients: A Case Study

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