Addressing Encephalitis Diagnosis in the Developing World Group Members: Jessica Barrett, Corey Bown, Angelina Ciocco, Leonor Hellmund, and Scott Jenkins

CASE STUDY WHO = 7 Year-old African boy, Baako Fofana WHAT = Develop insight into encephalitis (swelling of the brain as a result of infection) AND address possible new, realistic diagnostic solution WHERE = Undeveloped and rural Africa WHEN = NOW! WHY = Susceptible to contracting encephalitis via West Nile Virus, lack of complete vaccination, and limited available medical resources for identification and diagnosis

Current Problem Considerations CAUSES + CURRENT DIAGNOSTIC TOOLS + LIMITATIONS

Design Solution ❖ Handheld transcranial doppler (TCD) ultrasound to diagnose Encephalitis ❖ Device uses wifi to send obtained signals to larger hospitals/medical clinics in established towns or countries, where medical professionals can properly obtain the images and diagnose patients. ➢ Redces need to travel long distances to visit hospitals and obtain diagnosis ➢ Allows more patients to be diagnosed ❖ Models are used to gain insight into TCD functionality, the progression of Encephalitis, and the effects of Encephalitis on various parts of the brain. Created by Scott Jenkins

Model 1 - Leonor - Interaction between Cerebrospinal Fluid and Brain What physical problem are you addressing? Interaction between cerebrospinal fluid and brain for a normal patient, patient under critical condition and maximum pressure that can be caused by encephalitis. What quantitative information do you expect to obtain from your model? A better understanding of the pressure being applied on the brain by the ICP. Identify the deformation of the brain while a pressure is being applied. How will this information demonstrate one of the following: This will give insight on the brains response to ICP caused by encephalitis.

Model 1 - Leonor - Interaction between Cerebrospinal Fluid and Brain What are the physics? Solid mechanics What is the geometry? Half of the brain What are the boundary conditions? The upper brain is fixed and the lower part of the brain has a load being applied in the z direction. Loads being applied : 1.Normal pressure in brain: 7 mmhg 2.Critical pressure in brain: 15 mmhg 3.Maximum pressure in brain: 20 mmhg What is the material? Brain tissue material: Young Modulus: Poisson’s Ratio: Density:1076 Any details of meshing and solving? Physics controlled mesh Fine element size What did you do in post processing? Evaluating stresses caused by ICP in the brain.

Model 2 - Jessica - Middle Cerebral Artery (segment 1) What physical problem are you addressing? –TCD ultrasounds utilize the variation in blood flow velocity within MCA segment 1 (horizontal segment) to identify changes in ICP. This model simulates blood flow and pressure within the MCA when pressure is applied. What quantitative information do you expect to obtain from your model? – Blood velocity profile with an increased ICP at 15mmHg (a dangerous ICP for children and a potential ICP as a result of encephalitis ) – High pressure parts of the MCA – Deformation of MCA and surrounding tissue How will this information demonstrate one of the following: – Design feasibility (meeting a criteria / specification – Operation of device – Insight into medical problem being addressed

Model 2 - Jessica - Middle Cerebral Artery (segment 1) What are the physics? –Fluid Flow - Laminar flow –Solid Mechanics What is the geometry? –Tube with slight curvature (lumen/blood flow region) diameter at inlet = 3.1mm diameter at outlet = 2.9mm – Surrounding tube = 0.36mm thick (arterial wall) –Large block of ambiguous size (surrounding brain tissue) What are the boundary conditions? –average velocity =.6m/s –inlet flow rate = 3.406e-6m^3/s –outlet pressure = Pa What is the material? –user defined for all three materials: blood, arterial wall (averaged), and brain tissue (averaged) Any details of meshing and solving? –Physics controlled mesh –Fine element size What did you do in post processing? –Velocity Profile of blood –Surface stresses in arterial wall –Displacement of arterial wall

Model 2 - Jessica - Middle Cerebral Artery (segment 1) Velocity profilePressure between artery and blood flow Displacement of artery (expanded)

Model 3 - Angelina - Mechanics of intracranial Fluid Reaction with Skull Physical Problem Addressed – Interaction between cerebrospinal fluid and skull for both healthy patient and patient suffering from encephalitis Expected Quantitative Information from Model – Develop better understanding of the results of this pressure increase applied on the skull – Identify and evaluate regions of the skull that experience higher surface stress values Information Gained Demonstrates – Insight into intracranial relationship of fluid and skull for encephalitis patients

Model 3 - Angelina - Mechanics of intracranial Fluid Reaction with Skull Physics –Solid Mechanics Geometry –Hemi-Spherical Shell Thickness = 3mm Radius = mm Boundary Conditions Applied –Fixed Constraint: Shell Rim –Boundary Load 1: P (healthy) = Pa OR P (encephalitis) = Pa to Interior of Shell –Boundary Load 2: P = 0 Pa to Exterior of Shell Material –Bone Young’s Modulus = 11.8 GPa Poisson’s Ratio = 0.45 Density = 1600 kg/m3 Meshing and Solving –Physics Controlled Mesh –Element Size: Normal (issues and difficulty with anything finer) Post Processing –Evaluating surface stresses inside skull as a result of both healhty and elevated ICP values

Model 3 - Angelina - Mechanics of intracranial Fluid Reaction with Skull ICP Applied Stress on Seven Year-Old Skull Healthy ICP = 5 mmHG Encephalitis ICP = 15 mmHG

Model 4 - Corey - Virus Invasion Into Brain What physical problem are you addressing? –Arbovirus invasion into parenchyma of brain –Little is known about how the virus gets into the brain What quantitative information do you expect to obtain from your model? –The fraction of virus particles that are able to get into the brain through cell-cell junctions How will this information demonstrate one of the following: –This will give insight into encephalitis by investigating the likelihood of the arbovirus infecting the brain through endothelial cell junctions

Model 4 - Corey - Virus Invasion Into Brain What are the physics? o The physics being used are Laminar fluid flow and particle tracing for fluid flow What is the geometry? o Large cylinder: radius of 12 microns o Small Cylinder: radius of 4 microns  Both cylinders 90.6 microns long o Revolved rectangles around small cylinder: 15 microns by 1.5 microns  revolved degrees each What are the boundary conditions? o The exterior of the large cylinder creates a wall o Mean velocity at inlet is.79 mm/s o Revolved rectangles create an interior wall o Small cylinder is an open boundary

Model 4 - Corey - Virus Invasion Into Brain What is the material? o Fluid with density of 1060 kg/m^3 and viscosity of.0018 Pa*s  Blood o Virus particles 45 nm in diameter and a density of 1080 kg/m^3 Any details of meshing and solving? o An extremely fine triangular mesh was used around the cell walls o A free tetrahedral mesh was used for the rest What did you do in post processing? o Viewed different forms of velocity and pressure fields o Viewed particle positions at different times  Also played around with particle amounts

Model 4 - Corey - Virus Invasion Into Brain Blood Velocity Slice and Streamline Plot Virus Particles.06 Seconds into Invasion

Model 5 - Scott - Device Physical Problem –What material should be chosen for device case? Obtained from Model –Yield Loading for different case materials –Deformation at Yield Design Feasibility –Device must be able to survive environment –Case material must be cheap and easy to obtain

Model 5 - Scott - Device Physics –Structural Mechanics –Viscoelastic Behavior Geometry –Solidworks Model –Shelled Boundary Conditions –Fixed Constraint at handle –Varying Loads at Tip N Material –Polystyrene, ABS and Solving –Parametric Solver Utilized Post-Processing –Max stress at each load determined –Yield Predicted

Scott 3 PolyEthylene PVC

Created models proved the necessity and functionality of our wireless ultrasound device