1. Concept Review.1 KGCOE Multidisciplinary Sr. DesignR I T Instrument to Detect Thromboemboli in Blood Presenters: Evelyn Adames Carlos Cheek Thomas Fountain Trevor Hyde Robert Mahar Gabriela Noriega Eric Shyu Adam Wagner

2. Concept Review.2 KGCOE Multidisciplinary Sr. DesignR I T Outline Key Customer Needs & Specifications Identification & Justification of Critical Sub-functions Concept Development –Filter Paper –MRI –CAT Scan –Capacitance –Digital Imaging –Ultrasound –Light Scattering Next Steps

3. Concept Review.3 KGCOE Multidisciplinary Sr. DesignR I T Project Background Background & Motivation: –Cardiovascular devices provide a bridge to transplant or long term viable solution for Congestive Heart Failure (CHF) Patients. Surgery and medicine can not provide a solution Limited amount of donor hearts –Current Cardiovascular devices are thought to produce emboli There is currently no model for predicting emboli formation in cardiovascular devices. Mission Statement: –To develop a thromboemboli detector Will be used to evaluate blood damage induced by artificial heart.

4. Concept Review.4 KGCOE Multidisciplinary Sr. DesignR I T Key Needs & Specifications Key Customer Needs –Need 1 – Detect emboli in blood –Need 7 – System validation –Need 9 – Design of Surrogate Fluid Corresponding Specifications Spec No. Customer Need NumberDesign Specification Unit of Measure Marginal ValueIdeal Value 1 1.1, 1.2, 5.1, 5,2, 7.1, 7.2 Detection of particles and size within acceptable engineering uncertainty% Error15%10% 25.2Provides count of emboli detectedparticles/s5 particles/s 50 particles/s 31.2Indicates size of emboli detectedmicrons60 microns50 microns

5. Concept Review.5 KGCOE Multidisciplinary Sr. DesignR I T Concept Development Process Utilized Affinity Diagram to determine important design considerations based on most important customer needs described previously. –Ease of Implementation –Quality of Results –Safety –Customer Needs –Robust Based on discussion, initial concepts were developed. –Most important consideration: method of emboli detection device.

6. Concept Review.6 KGCOE Multidisciplinary Sr. DesignR I T Filter Paper Filter paper is often used to remove unwanted particles such as contaminants in a particular flow. –Sample flow at various time intervals –Use microscope to perform a manual count of emboli and observe size. –Subject to inaccuracy Need to conduct experiments to validate that the blood sample extracted from the experimental setup is characteristic of the entire flow. –Limited complexity and educational value to the team.

7. Concept Review.7 KGCOE Multidisciplinary Sr. DesignR I T MRI Uses Magnetic Resonance Imaging Radiation energy is released into the body, causing resonance in body cells. The amount of energy released by the cells indicated the type of cell. The depth of the image is dependant on the amount of energy released. –Pros Used in clot detection Non-invasive Detailed images –Cons Safety concerns –Death and injury has occurred from non-secured metallic and magnetic items in MRI room. Compatibility issues with magnetic components in CAD Cost (≈$4000 per Scan) Spatial resolution- Millimeter Scale Equipment operation

8. Concept Review.8 KGCOE Multidisciplinary Sr. DesignR I T CAT Scan –Uses X-ray Imaging X-ray images are taken at various depths. The depth is controlled by the amount of energy given off by the x-ray. –Pros Used in clot detection Noninvasive Few safety concerns –Cons Cost (≈$500 Per Scan) Spatial resolution- Millimeter Scale Equipment operation

9. Concept Review.9 KGCOE Multidisciplinary Sr. DesignR I T Capacitive Sensing Parallel plates are placed on either side of the blood volume to create a capacitor, with the blood acting as a dielectric. When an embolus passes through the capacitor, the dielectric constant changes slightly, resulting in a change in capacitance Would not be practical as the change in capacitance would be too small to accurately detect and relate to embolus size or number. Capacitance for parallel plate: C=kεA/d

10. Concept Review.10 KGCOE Multidisciplinary Sr. DesignR I T Digital Imaging Method One: A camera is used to capture images through a microscope. Microscope of 400x magnification 3MP digital camera with PC link Robust digital imaging analysis software Estimated Cost: –Microscope: ~$300 –Digital Coupler for 1xC- Mount: ~$400 –3.3MP Digital Microscope Camera: ~$3000 Method Two: By focusing a collimated light beam at a CCD/CMOS imager, it would be possible to detect particles as they passed between the imager and light source. –Resolution: 2um-25um. Estimated Cost –Light Source ~$300 –Collimator ~$100 –CCD ~$100

11. Concept Review.11 KGCOE Multidisciplinary Sr. DesignR I T Ultrasound A moving volume of blood is insonated with an ultrasonic transducer The reflected sound wave is converted to a voltage signal via the transducer This voltage signal can be processed to isolate the reflections caused by emboli which provide information about the quantity and size of the emboli Important Factors and Parameters –Center frequency and bandwidth of transducer –Pulsing rate of transducer –Attenuation of sound wave over a distance and through different mediums –Velocity of emboli –Angle of transducer relative to blood flow –Acoustic impedance of emboli relative to blood –Magnitude of reflected signal due to emboli

12. Concept Review.12 KGCOE Multidisciplinary Sr. DesignR I T Pros and Cons of Using Ultrasound Pros Minimum detectable emboli size (10microns possible) Availability of relevant research and on campus resources Ability to post process in frequency domain Ability to relate signals to particle composition Cons Difficulty of optimizing set up Small size of reflected signal Multiple Particle Interference (MPI) –Difficulty of differentiating emboli reflections from other reflections

13. Concept Review.13 KGCOE Multidisciplinary Sr. DesignR I T Initial Proposed Ultrasound Experimental Setup

14. Concept Review.14 KGCOE Multidisciplinary Sr. DesignR I T Light Scattering Relies on properties of the radiation of light, causing reflections and the detection of these reflections. Consists of two major parts – a laser diode and photo sensing receptor. Laser diode radiates into tube with fluid with multiple receptors at 90 deg angles.

15. Concept Review.15 KGCOE Multidisciplinary Sr. DesignR I T Laser Light Scattering Technology Pros Low power consumption Previous research has shown this method to work Minimum detectable emboli size: 60microns possible Required parts have been identified Cons Complex Signal Processing Multiple Particle Interference (MPI) Optimization of equipment placement

16. Concept Review.16 KGCOE Multidisciplinary Sr. DesignR I T Initial Proposed Light Scattering Experimental Setup Diagram 1Diagram 2

17. Concept Review.17 KGCOE Multidisciplinary Sr. DesignR I T Preliminary Experimentation Experimental Outcomes: –Qualitative understanding of how to conduct future experiments. Importance of Mounting Techniques Gathered basic equipment necessary A higher resolution digital oscilloscope is required. Syringe Laser Tubing Detector Experiment Setup:

18. Concept Review.18 KGCOE Multidisciplinary Sr. DesignR I T Critical Sub-functions Detection Technology –What technology will be selected for Emboli Detection? Power Conditioning –What will power the emboli detection device? Data Acquisition/ Signal Processing –Filters –Amplifiers –Analog/ Digital Conversion

19. Concept Review.19 KGCOE Multidisciplinary Sr. DesignR I T

20. Concept Review.20 KGCOE Multidisciplinary Sr. DesignR I T Pugh Selection Matrix Concepts Segment ABC (reference) Digital Image (CCD) Light ScatteringUltra Sound Selection CriteriaWeightRatingWtdRatingWtdRatingWtd Cost15%30.4520.302 Accuracy30%30.903 41.20 Ease of Implementation30%30.9020.602 Post Processing15%30.4520.302 Applicable Literature10%30.3040.404 Total Score3.002.502.80

21. Concept Review.21 KGCOE Multidisciplinary Sr. DesignR I T Next Steps Select one of the two remaining technologies –Ultrasound –Light Scattering Begin to Develop Models –Mathematical Models –Diagrams –Experimental Setup

22. Concept Review.22 KGCOE Multidisciplinary Sr. DesignR I T Risk Assessment The team has arrived at the following conclusion: –The risk between Ultrasound and Light Scattering is the same based on research and our subject knowledge. –Digital Imaging is a novel approach to achieve the project goal and one that we plan on pursuing. By following two separate technology paths we minimize the risk of redundant failure.