Miami, FL September 11-15, 2012

Transcription

1 TBI Assessment Based on Biomechanical Modeling of Brain Tissue at the Cellular Level Under Blast Loading Mariusz Ziejewski, Ph.D., Inż and Ghodrat Karami, Ph.D. North American Brain Injury Society Presenter Mariusz Ziejewski, Ph.D., Inż Professor Director of Impact Biomechanics Laboratory, College of Engineering Director of Automotive Systems Laboratory, College of Engineering Mechanical Engineering Department North Dakota State University and Adjunct Associate Professor Department of Neuroscience, School of Medicine University of North Dakota Miami, FL September 11-15, 2012

2 Involvement with Department of Defense Researcher: 1. Armstrong Aerospace Medical Laboratory, Wright Patterson Air Force Base 2. ~900 tests analyzed with humans male/female 3. Seven (7) research contracts, Current, $600,000 grant, Blast Pressure Gradients and Fragments on Ballistic Helmets and the Head and Brain Injury Simultaneous Multiscale Modeling with Experimental Validation, Department of the Army, US Army Research, Development and Engineering Command ( ) 5. Current, $500,000 grant, Blast and the Consequences on Traumatic Brain Injury Mulitscale Mechanical Modeling of Brain Air Force Office of Scientific Research, ( ) Chair: 1. Chairman, Scientific Peer Review Panel, Proposals, Integrated Eye Tracking and Neural Monitoring for Enhanced Assessment of Mild TBI, United States Medical Research and Materiel Command (USARMC), DoD Psychological Health, Polytrauma, and Operational Health (PHPOH) Program. (2012) 2. Chairman, Scientific Peer Review Panel, Physics of Blast as it relates to Brain Injury, Intramural proposals, DoD PTSD/TBI Research Program, Congressionally Directed Medical Research Program (CDMRP). (2007) 3. Chairman, Scientific Peer Review Panel, Physics of Blast as it relates to Brain Injury, Extramural proposals, DoD PTSD/TBI Research Program, CDMRP. (2007) Reviewer: 1. Reviewer, Proposals for United States Army Medical Research and Materiel Command (USARMC) Psychological Health, Polytrauma, and Operational Health (PHPOH) Program (2012) 2. Reviewer, Proposals for United States Medical Research and Materiel Command (USARMC) Warrior Injury Assessment Manikin (WIAMan) Program (2012) 3. Reviewer, Proposals for United States Medical Research and Materiel Command (USAMRMC) Military Medical Research and Development Grant Program (2010, 2011) 4. Reviewer, Intramural Proposals for the Department of Defense (DoD) Defense Medical Research and Development Program, Intramural Applied Research and Advanced Technology Development Award (2009) 5. Reviewer, Proposals for the Military Operational Medical Research Program, US Army Materiel Research Command (USAMRMC).(2008) 6. Reviewer, Intramural Proposals for the Department of Defense (DoD) Intramural War Supplement Program.(2008) 7. Reviewer, Scientific Peer Review Panels, Concept Proposals related to brain injuries caused by blasts for the DoD (PTSD/TBI) Research Program, CDMRP. (2007) 8. Reviewer, Scientific Peer Review Panels, Intramural Proposals on Clinical Diagnosis related to brain injuries caused by blasts for the DoD (PTSD/TBI) Research Program, CDMRP. (2007) Invited Faculty: 1. Invited Faculty, Invited by former US Air Force Surgeon General P.K. Carlton to make a presentation on the Physics of Blast Injury to a special conference/think tank session on allocation of Department of Defense (DoD) funding for TBI/blast injuries. 2. Invited Faculty, National Veteran s Health Administration/Department of Defense (VHA/DoD) Conference: Visual Consequences of Traumatic Brain Injury. 3. Invited Faculty, National Veteran s Health Administration/Department of Defense (VHA/DoD) Conference: Sensory Impairment Issues in Traumatic Brain Injury.

3 Direction of Our Research (Sponsored by DoD) Multiscale modeling method proposed for brain cell adhesion modeling: (a) MD (molecular dynamics)simulation of Cell-ECM (extracellular matrix)interaction (b) Average traction-separation data from MD simulation (c) Axon- ECM continuum modeling of the interface (d) Undulated RUC (repeating cell unit) of brain material and fiber reinforced composite modeling of the tissue (e) Micromechanics modeling of RUC under different load cases for material characterization

4 Invisible Injury macro scale (mm) (10-3 m) MRI detection limit Fig. A, B, C Diffusion Tensor Imaging (DTI) 1x1x5 mm 3 Susceptibility Weighted Imaging (SWI) 0.2x0.2x0.2 mm 3 micro scale (μm) (10-6 m) the cell Fig. D MR Microscopy (MRM) 100 μm 3, Tesla Performed only on autopsied brain nano scale (nm) (10-9 m) the axon neural filaments Fig. E Electron microscope to visualize Carpenter, M., Human Neuroanatomy. Baltimore, MD: Williams and Wilkins, 1976 Williams TH, Gluhbegovic N. Jew JY. The human brain: dissections of the real brain. Virtual Hospital, University of Iowa, 1997; and [21/10/22] Callot, et. al, Short-scan-time multi-slice diffusion MRI of the mouse cervical spinal cord using echo planar imaging, NMR in Biomedicine, 2008

5 BIOMECHANICS the application of the principles and techniques of mechanics to the structure, functions and capabilities of living organisms. Webster s New World Dictionary of the American Language Ed. David B. Guralnik. 2 nd College Ed. New York: World Pub. Co., 1970

6 IMPACT NEUROTRAMA (Traumatic Brain Injuries) APPLICATION OF FORCE RAPID HEAD VELOCITY CHANGE LINEAR ANGULAR BRAIN DEFORMATION BRAIN DAMAGE CHANGE TO SHAPE CHANG E TO VOLUME NEURONAL (DAI) VASCULAR CYTOSKELERAL STRUCTURE

7 Accelerometer

8 TYPES OF ACCELERATION Linear Acceleration Rotational Acceleration Z Y X A x = Linear Acceleration, Forward-Backward Direction Ay = Linear Acceleration, Side to Side Direction A z = Linear Acceleration, Vertical Direction a x = Rotational Acceleration, About Forward-Backward Axis a y = Rotational Acceleration, About Side to Side Axis a z = Rotational Acceleration, About Vertical Axis

9 TYPES OF ACCELERATION Linear Acceleration Rotational Acceleration Z Y X A x = Linear Acceleration, Forward-Backward Direction Ay = Linear Acceleration, Side to Side Direction A z = Linear Acceleration, Vertical Direction a x = Rotational Acceleration, About Forward-Backward Axis a y = Rotational Acceleration, About Side to Side Axis a z = Rotational Acceleration, About Vertical Axis

10 TYPES OF ACCELERATION Linear Acceleration Rotational Acceleration Z Y X A x = Linear Acceleration, Forward-Backward Direction A y = Linear Acceleration, Side to Side Direction A z = Linear Acceleration, Vertical Direction a x = Rotational Acceleration, About Forward-Backward Axis a y = Rotational Acceleration, About Side to Side Axis a z = Rotational Acceleration, About Vertical Axis

11 TYPES OF ACCELERATION Linear Acceleration Rotational Acceleration Z Y X A x = Linear Acceleration, Forward-Backward Direction A y = Linear Acceleration, Side to Side Direction A z = Linear Acceleration, Vertical Direction a x = Rotational Acceleration, About Forward-Backward Axis a y = Rotational Acceleration, About Side to Side Axis a z = Rotational Acceleration, About Vertical Axis

12 TYPES OF ACCELERATION Linear Acceleration Rotational Acceleration Z Y X A x = Linear Acceleration, Forward-Backward Direction A y = Linear Acceleration, Side to Side Direction A z = Linear Acceleration, Vertical Direction a x = Rotational Acceleration, About Forward-Backward Axis a y = Rotational Acceleration, About Side to Side Axis a z = Rotational Acceleration, About Vertical Axis

13 TYPES OF ACCELERATION Linear Acceleration Rotational Acceleration Z Y X A x = Linear Acceleration, Forward-Backward Direction A y = Linear Acceleration, Side to Side Direction A z = Linear Acceleration, Vertical Direction a x = Rotational Acceleration, About Forward-Backward Axis a y = Rotational Acceleration, About Side to Side Axis a z = Rotational Acceleration, About Vertical Axis

14 TYPES OF ACCELERATION Linear Acceleration Rotational Acceleration Z Y X A x = Linear Acceleration, Forward-Backward Direction A y = Linear Acceleration, Side to Side Direction A z = Linear Acceleration, Vertical Direction a x = Rotational Acceleration, About Forward-Backward Axis a y = Rotational Acceleration, About Side to Side Axis a z = Rotational Acceleration, About Vertical Axis

15 TYPES OF ACCELERATION Linear Acceleration Rotational Acceleration Z Y X A x = Linear Acceleration, Forward-Backward Direction Ay = Linear Acceleration, Side to Side Direction A z = Linear Acceleration, Vertical Direction a x = Rotational Acceleration, About Forward-Backward Axis a y = Rotational Acceleration, About Side to Side Axis a z = Rotational Acceleration, About Vertical Axis

16 Human Head Model

17 FE Modeling of the Human Helmeted Head Head Components: Scalp Skull Dura Mater CSF Pia mater Falx Brain Tentorium Mechanical Properties: Facial bone Head component Young s modulus (GPa) Density Element type Number of elements Neck Skull E-6 Solid element 8305 Dura mater E-6 Shell element 2125 Tentorium E-6 Shell element 230 Falx E-6 Shell element 235 Pia mater 1.150E E-6 Shell element 2754 Facial bone E-6 Solid element 1124 Neck E-6 Solid element 3772 Scalp E-6 Solid element 5938 CSF E-6 Solid element 3354

18 Mechanical Properties of Brain Tissue Incompressible (High resistance to change in size, high bulk modulus) Deformable (Low resistance to change in shape, low shear modulus)

19 B.R. Donnelly and J. Medige, Shear Properties of Human Brain Tissue, Journal of Biomechanical Engineering, Nov. 1997, Vol. 119, Shames, I.H. and Cozzarelli, F.A., 1992, Elastic and Inelastic Stress Analysis, New Jersey: Prentice Hall, Englewood Cliffs, NJ Incompressible/Deformable Bulk modulus is approximately 10 5 (100,000) times larger than shear modulus. Deformation of brain tissue can be assumed to depend on shear modulus only. This behavior is common with viscoelastic materials (Shames and Cozzarelli, 1992)

20 Mechanical Properties of Brain Tissue Heterogeneous (Different properties within the brain) Anisotropic (Different properties in different directions)

21 Repeating Unit Cell - Homogenization Method The distribution of undulated axons inside the extracellular matrix for a guinea optic nerve microstructure (Meaney, 2003) simulated periodic sinusoidal undulated distribution of axons, with the corresponding periodic unit cell RUC representing undulated periodic microstructure of the composite tissue N. Abolfathi, M. Sotudeh, A. Naik, G. Karami and M. Ziejewski, A micromechanical procedure for the anisotropic modeling of mechanical properties of brain white matter, Computer Methods in Biomechanics and Biomedical Engineering 2009;12(3),

22 Axon-ECM Stress Distribution Results (c) (d) (b) (a) Illustration of the tensile stresses (S 11 ) developed in the (a) axons; (b) matrix and; the (c) tissue unit cell (d) The deformed shape of the axon with respect to its original shape is also shown in. Abolfathi N., Naik A., Sotudeh M., Karami G. and Ziejewski M. A micromechanical procedure for characterization of the mechanical properties of brain white matter Computer Methods in Biomechanics and Biomedical Engineering, 2009 (in press, available online, DOI: / ).

23 Repeating Unit Cell - Homogenization Method (a) Approximation of axons distribution inside the histology slide showing typical cross-section of the adult porcine brainstem (Abrogast and Margulies, 1999) (b) (b) Approximated random distribution (c) Hexagonal distribution (c) (d) Simulated square distribution (a) (d) Venkata Dirisala, Ghodrat Karami and Mariusz Ziejewski, A Biomechanical Investigation Of Primary Blast Head Injury Using Finite Element Methods, Annals of Biomedical Engineering (submitted) N. Abolfathi, M. Sotudeh, A. Naik, G. Karami and M. Ziejewski, A micromechanical procedure for the anisotropic modeling of mechanical properties of brain white matter, Computer Methods in Biomechanics and Biomedical Engineering 2009;12(3),

24 Mechanical Properties of Brain Tissue Viscoelastic (Time dependent properties: magnitude, duration, rate of change)

25 Viscoelastic Materials: Exhibit both viscous and elastic characteristics

26 Demonstration Slow Application of Force Rapid Application of Force

27 Visualization of INTERNAL Damage Test # 1 Impact severity ~7.5 J Low velocity (2.2 mph) Large mass (39.5 lb) Low Velocity Test # 2 Impact severity ~7.5 J High velocity (69 mph) Small mass (0.03 lb) High Velocity

28 Visualization of INTERNAL Damage Test # 1 Impact severity ~7.5 J Low velocity (2.2 mph) Large mass (39.5 lb) Low Velocity Test # 2 Impact severity ~7.5 J High velocity (69 mph) Small mass (0.03 lb) High Velocity

29 (kpa) Uniqueness of the Loading Conditions μs Supersonic overpressurization shockwave Timescale in μs (microseconds) 1atm 100 kpa

30 (kpa) Uniqueness of the Loading Conditions μs Supersonic overpressurization shockwave Timescale in μs (microseconds) 1atm 100 kpa

31 Relative Motion of the Brain

32 Coup and Counter-Coup Phenomena at the early stage (a) (b)

33 Coup and Counter-Coup Phenomena at the early stage Countercoup (C, D) Coup (A, B) (a) (b)

34 Blast Brain Trauma Countercoup (C, D) Coup (A, B) (a).0002s (b) Extremely Dynamic Oscillation of the Brain Tissue Ziejewski, M. and Karami, G., Biomechanical Perspective on Blast Injury, in Concussive Brain Trauma: Neurobehavioral Impairment and Maladaptation by Dr. Rolland Parker, Taylor & Francis Group, Boca Raton, FL, 2012

35 Properties Comparison Silicon Gel & Brain Tissue Brands, D., P. Bovendeered, G. Peter, et al. Comparison of the Dynamic Behaviour of Brain Tissue and Two Model Materials, SAE 99C21, Society of Automotive Engineers, Inc

36 Skull/Gel Model Testing Test Conditions (per ATB Simulation) : Severity of Impact (X = 10.10g, Y = 14.09g, Z = 4.02) Tested at Y = 10.55g Position of Head (Yaw 75º, Pitch 7º, Roll 6º) Video Parameters: Capture rate: 10,000 frames/sec Slow motion (1/60th of actual velocity)

37 Skull/Gel Model Testing Test Conditions (per ATB Simulation) : Severity of Impact (X = 10.10g, Y = 14.09g, Z = 4.02) Tested at Y = 10.55g Position of Head (Yaw 75º, Pitch 7º, Roll 6º) Video Parameters: Capture rate: 10,000 frames/sec Slow motion (1/60th of actual velocity) Transformed MRI Data Source of Original Data: Dr. Orrison, Nevada Imaging Centers

38 Skull/Gel Model Testing Test Conditions (per ATB Simulation) : Severity of Impact (X = 10.10g, Y = 14.09g, Z = 4.02) Tested at Y = 10.55g Position of Head (Yaw 75º, Pitch 7º, Roll 6º) Video Parameters: Capture rate: 10,000 frames/sec Slow motion (1/60th of actual velocity) Transformed MRI Data Source of Original Data: Dr. Orrison, Nevada Imaging Centers Dynamic Pattern at Impact Approach Rebound

39 (kpa) Uniqueness of the Loading Conditions μs Supersonic overpressurization shockwave Timescale in μs (microseconds) 1atm 100 kpa

40 (kpa) Cavitation Automotive Blast Supersonic overpressurization shockwave (>300m/s) Pressure increased to MPa (1atm 100 kpa) Timescale in μs (microseconds)

41 Cavitation Liquid Jet Scanning Electron Micrograph Brass Plate ~ 1 mm Crater

42 Cavitation Liquid Jet Scanning Electron Micrograph Brass Plate ~ 1 mm Crater

43 CAVITATION DAMAGE Macroscale Bubble Collapse (Classical Approach) A. Spherical Bubble Collapse Nanoscale Bubble Inception (New Brain Injury Mechanism) Mass Spring Fracture Point Mass Spring B. Non-Spherical Bubble Collapse Liquid Jet Recoil pressure waves

44 Shear Strain Response Taber, k.h. et al., J Neuropsychiatry Clin Neurosci 18: , May 2006 Area of Damage: Cortical surface Central core region Cerebellum Brain stem

45 Shear Stress Response Taber, k.h. et al., J Neuropsychiatry Clin Neurosci 18: , May 2006 Area of Damage: Brain stem Max. Shear stress distribution on sagittal section (1 lb TNT)

46 Thank You