The role of blood flow in aneurysm pathophysiology and treatment

- @neurIST, Physiome- voxel, pixel, phyxel, bioxel- flow in aneurysms- flow in the intracranial compartment- homeostasis, allostasis

daniel.rufenacht@sim.hcuge.ch

www.neuroimaging.ch

STEP 15 / 16.5.2006 - a strategy for the EUORPHYSIOME - FP7

PixelPicture (Pics, Pix) and element

VoxelVolume and pixel(spatial aspects)

Bioxel (biological element)integration of allbiological and physical parameters allowing for modelling of life in a virtual environment to understandhomeostasic and allostasic mechanismsof biological systems

Phyxel (physical element)

4D - pixel (temporal aspects)

RealHuman

VirtualReplicaof Human

Converging technologies

Mission statement:

@neurIST will develop an IT infrastructure for the management and processing of heterogeneous data associated with the diagnosis and treatment of cerebral aneurysm and subarachnoid haemorrhage. The data span all length scales, from molecular, through cellular to tissue, organ and patient representations. These data are increasingly heterogeneous in form, including textual, image and other symbolic structures, and are also diverse in context, from global guidelines based on the broadest epidemiological studies, through knowledge gained from disease-specific scientific studies, to patient-specific data from electronic health records. New methods are required to manage, integrate and interrogate the breadth of data and to present it in a form that is accessible to the end user. FP6http://aneurist.org

Initiation

GrowthRupture

Humphrey JDCardiovascular solid mechanics2001

2-4%2000-4000/100K

10/100K/y

Humphrey JDCardiovascular solid mechanics2001

Humphrey JDCardiovascular solid mechanics2001

oscillatory shear stress

@neuEndoWCE – ANSYS

IDAC – ASD

@neuRiskINF - PMS

How will the results precisely impact on the targeted groups?

Improve decision making processes in the management of unruptured aneurysms by providing a score that integrates all the available information for identifying at-risk patients and reducing current over treatment

Support computational design processes towards a next generation of smart flow-correcting implants to treat ruptured aneurysms and reduce current treatment costs, side effects and recurrence.

Support the knowledge discovery for linking genetics to disease, vasospasm and blood clotting after cerebral hemorrhage

@neurISTSystems

WSS

3DRA

CFDCFD

PC-MR vs USFlow rates

CFD vs USPeak velocity

Model& WSS

magnitude phasemagnitude phase

Support the integration of modeling, simulation and visualization of multimodal data

@neuCompute/InfoNEC – GS – ANSYS

Support integration of data and computing resources.

@neuFuseB3C – PMS

Supp

ort T

ools

Enab

ling

IT

@neuLinkSCAI (Roche, Actelion)

BalloonAneurysm

Filling

Coil Aneurysm

Filling

Stent-AssistedCoiling

Flow DiversionVessel Repair

1985 1990 2005 2010

Cebral JR, Putman C - G. Mason Univ., Fairfax, VA

Image guided minimal invasive treatment methods:Endovascular repair of cerebral arteries based on 3D imaging data: Converging Technologies

MedicalImaging

3D dataset

DSA,MR,CT

Patient

database

Treatment

control

Medical

Informatics,

Flow-/ Wall-

Biomech.

Simulation- Validation (numeric,

in-vitro, …)

CFD

PIV / LDV

Flow-correction

Rupture risk

assessment;

Stent design CAD

MedicalDevice

Stent

material

Stent

delivery

Stent

Treatment

outside wall inside

perianeurismal

environment

tissue, shape,

biomechanics

blood flow

rheology

Weir B

Wiebers DO, et al. NER Symposium, ASNR’03

Autoregulation: Flow in collapsible veins - CBF Autoregulation: Flow in collapsible veins - CBF

1. Increased ICP increases outflow obstruction

2. The vascular resistance of the microvascularbed decreases at increased ICP (within certain limits)

• Venous autoregulation of global CBF

D Greitz: Int J Neurorad 1997

1.

2.

Autoregulation of CBF and CSF (Homeostasis)Autoregulation of CBF and CSF (Homeostasis)

1. Homeostasis (“stability through constancy”) of brain and CSF circulation can adapt to parameter changes in a limited range.

2. Under pathological conditions such as Trauma, Hemorrhage, Thrombosis, Ischemia, etc. the homeostatic mechanisms are unable to cope with the demands placed on them (acutely, chronically).

3. Allostasis (“stability through change”) allows for reaching conditions of a new balance in such pathological conditions (“fitness under natural selection”).

4. Only numerical simulation may help to understand such complex conditions and suggest ways of medical therapy, i.e. corrections that may lead to a new equilibrium for a system in trouble.

P Sterling: Principles of allostasis, 2004