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www.heartandstroke.com
Thermal Fluids Modeling of Localized Hypothermia in a Canine Brain
Graduate Student: Ryan A. Sikorski Thesis Advisor: Dr. Thomas L. MerrillRowan University Department of Mechanical EngineeringAugust 2nd 2013
Committee Members:Dr. Smitesh BakraniaDr. Krishan BhatiaDr. Jennifer Vernengo
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Google Image
Reperfusion Injury and Therapeutic HypothermiaReperfusion Injury and Therapeutic Hypothermia1Other Published Therapeutic Hypothermia ResearchOther Published Therapeutic Hypothermia Research
Previous Models and Final Model GeometryPrevious Models and Final Model Geometry
ResultsResults
Conclusions and Future WorkConclusions and Future Work
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CNN Tech
Mechanical ThrombectomyMechanical Thrombectomy
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CNN Tech
Reperfusion InjuryReperfusion Injury
Paradox – reperfusion sustains, reperfusion damages
Inflammation to the tissue
Metabolic rate of brain reduced 6-10% per 1°C
Therapeutic Hypothermia -What is the critical temperature range?
What 5 critical questions should be answered
Paradox – reperfusion sustains, reperfusion damages
Inflammation to the tissue
Metabolic rate of brain reduced 6-10% per 1°C
Therapeutic Hypothermia -What is the critical temperature range?
What 5 critical questions should be answered
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CNN Tech
Author StudyTissue
TemperatureResults
Van der Worp, 2007
‐ Animal meta study, 101 different publications, 3300 animals
‐ Best results, < 33°C
‐ Usage of TH improves outcomes by 30%
Schwab, 1998 ‐ Human external cooling
‐ 32 ‐ 33°C, 14 hours
‐ Intracranial pressure reduced
Krieger, 2001 ‐Human surface cooling hypothermia
‐ 32 ±1 °C, 12 – 72hours
‐ Feasible and safe in patients
Neimark, 2007, 2011
‐ Predictive model / Safety trial
‐ Estimated temperature reduction of 2.8°C
‐ No major complications‐ Simple quantitative
model
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CNN Tech
Problem StatementProblem Statement
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Summer 2012 – Predict tissue temperature in a human thermal fluids model.
Summer 2013 – Predict blood temperature’s in a physiologically accurate canine intracranial model
Summer 2012 – Predict tissue temperature in a human thermal fluids model.
Summer 2013 – Predict blood temperature’s in a physiologically accurate canine intracranial model
1) Summer 2012Benchmark Models, Human Carotid Bifurcation
- Comsol Conference 2012: Paper & Poster
2) Fall 2012, Winter 2013
In-vitro canine, CFD model
- ASME Design of Medical Device Conference: Paper &Poster
- ASME Bioengineering Conference 2013: Poster
3) Spring/Summer 2013Physiological AccurateCanine Blood Model
- ASME Journal of Medical Devices: Technical Brief
Work CompletedWork Completed
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Modeling AssumptionsModeling Assumptions
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Assumption Reasoning
1) Steady State< 5% effect on thermal problems, balloon occlusion
2) Rigid VesselFluid-structure interaction complexity, reasonable assumption [Waite]
3) Newtonian FlowVessel diameter is much larger than blood cell, < 5% velocity differential [Steinman]
4) Inlet Laminar Flow Catheter length >> Entry length
5) Constant Wall Temperature Blood only model
Governing EquationsGoverning Equations
Steady State ‐ Three Dimensional Navier‐Stokes Equations
Steady State ‐Thermal Energy Equation
+ Q +
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CNN Tech
Previous ModelsPrevious Models
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Linking the experimental and the computational Linking the experimental and the computational
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Circle of WillisCircle of Willis
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Area of modeling interest
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In-Vivo WorkIn-Vivo Work
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In-Vivo WorkIn-Vivo Work
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100 ml/min 50 ml/min 70 ml/min
Inner Carotid Artery
Middle Cerebral Artery
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1) Research canine anatomy journals and textbooks2) Start simple, add complexity3) Receive feedback from experts - Matt Gounis, etc.4) Iterate 5) Fine tune for meshing
1) Research canine anatomy journals and textbooks2) Start simple, add complexity3) Receive feedback from experts - Matt Gounis, etc.4) Iterate 5) Fine tune for meshing
Building a Physiologically Accurate ModelBuilding a Physiologically Accurate Model
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0 200,000 400,000 600,000 800,000 1,000,000 1,200,000 1,400,000
Percent Difference In
let Mass Flow Rate : Outlet Mass Flow Rate
Number of Elements ‐ Fluid Domain
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Comsol SettingsComsol Settings
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Boundary Condition Value
Artery Inlet No Flow, Fully Occluded ‐
Catheter Inlet Laminar Inflow, Velocity 0.35 – 0.64 [m/s]
All Flow Outlets Pressure No Viscous [Taylor] 0 [Pa]
Wall Boundaries No Slip ‐
Blood/Wall Thermal Conductivity
Constant 0.45 / 0.49[W/(m*K)]
Artery Wall Temperature
Temperature 311.65 [K]
Catheter InletTemperature
Temperature, Varies with Flow 295 – 296.5 [K]
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LocationVolumetric Flow Rate [ml/min]
% of 90 ml/min total flow
1 42.7424 47.49%2 6.6838 7.43%3 12.4511 13.83%4 16.6755 18.53%5 4.8135 5.35%6 0.5385 0.60%7 1.9282 2.14%8 4.8518 5.39%
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0 20 40 60 80 100 120 140 160
Temperature [K]
S ‐ Length ]mm]
Branch #1
Branch #2
Branch #3
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Temperature [K]
S ‐Length [mm]
60 ml/min
80 ml/min
100 ml/min
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Temperature [K]
S‐Length [mm]
60 ml/min
80 ml/min
100 ml/min
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5 15 25 35 45 55 65
Temperature [K]
S‐Length [mm]
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80 ml/min
100 ml/min
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2.5 4.5 6.5 8.5 10.5 12.5 14.5 16.5
Temperature [K]
S‐Length [mm]
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80 ml/min
100 ml/min
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Temp [K]
Volumetric Flow Rate [ml/min]
Computational Blood, 40mmalong bifurcation path
In‐vivo tissue 10 minutes
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1) Constant Wall Temperature2) Steady State3) Based on Two-Dimensional Angiograms4) No Tissue Domain
1) Constant Wall Temperature2) Steady State3) Based on Two-Dimensional Angiograms4) No Tissue Domain
Model LimitationsModel Limitations
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Proposed Future WorkProposed Future Work
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1. Address limitations2. Increase computational capacity, switch to
finite volume solver3. Transition to human model, building off of
canine work4. Incorporate scanned images to construct
accurate 3D model
1. Address limitations2. Increase computational capacity, switch to
finite volume solver3. Transition to human model, building off of
canine work4. Incorporate scanned images to construct
accurate 3D model
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• Rowan University • Department of Mechanical Engineering• Barbara Wynn • Faculty and Lab Staff• South Jersey Technology Park
• FocalCool, LLC• Denise Merrill• Jennifer Mitchell • Madina Yermagambetova• Anthony La Barck
• Graduate Students• Dylan McNally• Jared Wasserman
• Thesis Committee• Dr. Smitesh Bakrania• Dr. Krishan Bhatia• Dr. Jennifer Vernengo
• Thesis Adviser • Dr. Thomas Merrill
• Mom + Dad
AcknowledgementsAcknowledgements
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ReferencesReferences
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[1] “Heart and Stroke Foundation,” 2013. [Online]. Available: http://www.heartandstroke.com/site/c.ikIQLcMWJtE/b.3484151/. [Accessed: 08‐Jan‐2013].[2] “Merci Retriever,” 2013. .[3] H. B. van der Worp, E. S. Sena, G. a Donnan, D. W. Howells, and M. R. Macleod, “Hypothermia in animal models of acute ischaemic stroke: a systematic review and meta‐analysis.,” Brain : a journal of neurology, vol. 130, no. Pt 12, pp. 3063–74, Dec. 2007.[4] W. S. Smith, G. Sung, J. Saver, R. Budzik, G. Duckwiler, D. S. Liebeskind, H. L. Lutsep, M. M. Rymer, R. T. Higashida, S. Starkman, Y. P. Gobin, D. Frei, T. Grobelny, F. Hellinger, D. Huddle, C. Kidwell, W. Koroshetz, M. Marks, G. Nesbit, and I. E. Silverman, “Mechanical thrombectomy for acute ischemic stroke: final results of the Multi MERCI trial.,” Stroke; a journal of cerebral circulation, vol. 39, no. 4, pp. 1205–12, Apr. 2008.[5] NINDS t‐PA Stroke Study Group, “Tissue plasminogen activator for acute ischemic stroke,” New England Journal of Medicine, vol. 333, pp. 1581–1587, 1995.[6] T. Merrill, D. R. Merrill, and J. Akers, “Localized Brain Tissue cooling For Use During Intracranial Thrombectomy,” 2012.[7] H. B. van der Worp, M. R. Macleod, and R. Kollmar, “Therapeutic hypothermia for acute ischemic stroke: ready to start large randomized trials?,” Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism, vol. 30, no. 6, pp. 1079–93, Jun. 2010.[8] S. Schwab, S. Schwarz, M. Spranger, E. Keller, M. Bertram, and W. Hacke, “Moderate Hypothermia in the Treatment of Patients With Severe Middle Cerebral Artery Infarction,” Stroke, vol. 29, no. 12, pp. 2461–2466, Dec. 1998.[9] S. Schwab, S. Schwarz, M. Spranger, E. Keller, M. Bertram, and W. Hacke, “Moderate Hypothermia in the Treatment of Patients With Severe Middle Cerebral Artery Infarction,” Stroke, vol. 29, no. 12, pp. 2461–2466, Dec. 1998.[10] M. a Neimark, A.‐A. Konstas, A. F. Laine, and J. Pile‐Spellman, “Integration of jugular venous return and circle of Willis in a theoretical human model of selective brain cooling.,” Journal of applied physiology (Bethesda, Md. : 1985), vol. 103, no. 5, pp. 1837–47, Nov. 2007.[11] M. a Neimark, A.‐A. Konstas, J. H. Choi, A. F. Laine, and J. Pile‐Spellman, “Brain cooling maintenance with cooling cap following induction with intracarotid cold saline infusion: a quantitative model.,” Journal of theoretical biology, vol. 253, no. 2, pp. 333–44, Jul. 2008.[12] A.‐A. Konstas, M. a Neimark, A. F. Laine, and J. Pile‐Spellman, “A theoretical model of selective cooling using intracarotid cold saline infusion in the human brain.,” Journal of applied physiology (Bethesda, Md. : 1985), vol. 102, no. 4, pp. 1329–40, Apr. 2007.[13] E. Tanaka, a Tanaka, T. Sekka, Y. Shinozaki, K. Hyodo, K. Umetani, and H. Mori, “Digitized cerebral synchrotron radiation angiography: quantitative evaluation of the canine circle of Willis and its large and small branches.,” AJNR. American journal of neuroradiology, vol. 20, no. 5, pp. 801–6, May 1999.[14] B.‐T. Kang, D.‐P. Jang, S.‐H. Gu, Y.‐B. Kim, C.‐Y. Lim, J.‐H. Lee, E.‐J. Woo, Z.‐H. Cho, and H.‐M. Park, “Three‐dimensional time‐of‐flight magnetic resonance angiography of intracranial vessels in a canine model of ischemic stroke with permanent occlusion of the middle cerebral artery.,” Comparative medicine, vol. 59, no. 1, pp. 72–7, Feb. 2009.[15] J. Hendrikse, a F. van Raamt, Y. van der Graaf, W. P. T. M. Mali, and J. van der Grond, “Distribution of cerebral blood flow in the circle of Willis.,” Radiology, vol. 235, no. 1, pp. 184–9, Apr. 2005.[16] L. Waite and J. Fine, Applied Biofluid Mechanics. New York, NY: McGraw‐Hill, 2007.[17] T. L. Merrill, D. R. Merrill, T. J. Nilsen, and J. E. Akers, “Design of a cooling guide catheter for rapid heart cooling,” ASME Journal of Medical Devices, vol. 4, no. 3, pp. 035001–1 – 035001–8, 2010.[18] K. Perktold, M. Resch, and H. Florian, “Pulsatile Non‐Newtonian Flow Characteristics in a 3‐Dimensional Human Carotid Bifurcation,” Journal of Biomechanical Engineering, no. 113, pp. 467–475, 1991.
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