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Prof Peter Bryanston-Cross School of Engineering

Imaging in difficult environments: The digital Ophthalmoscope and the potential creation of a low cost capillary imaging system. Prof Peter Bryanston-Cross School of Engineering. Rolls-Royce Trent 800 engine with serrated nozzle to reduce engine noise.

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Prof Peter Bryanston-Cross School of Engineering

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  1. Imaging in difficult environments: The digital Ophthalmoscope and the potential creation of a low cost capillary imaging system Prof Peter Bryanston-Cross School of Engineering

  2. Rolls-Royce Trent 800 engine with serrated nozzle to reduce engine noise

  3. Time & Cost Each engine test costs £200k and is completed in 10days Method: Inject 0.8 micron particles in to the 1500oC 300Km/hr flow Measurement: Imaging of the particles Data Resolution 100 microns over 48 ‘stitched 200mmx200mm frames Processing: Stereo PIV (Particle Image Velocimetry) Deliverables: Complete velocity mapping of the exhaust in 3D in 3 hrs Processing: 3 months to process 10 Tbytes of data

  4. Optical Medical instrumentation

  5. As part of a feasibility project a survey was made as to the diagnostics medical practitioners use in the process of a typical consultation. • Typical consultation • 5-10 minutes reading patients notes • Assess facial colouring, signs of a flush for example • Discuss with the patient their symptoms • Measure blood pressure • Measure pulse • Lack of Diagnostic Information • No previous diagnostic history other than text • No self monitoring information • Some instruments considered too difficult to use • 70% likely outcome : If thing do not change come back next week. • 5% likely out come: referred to hospital or specialist.

  6. Existing Devices: ECG & Digital Stethoscope • Electro Cardio Graph • Cardio24

  7. Existing Devices: Pulse Oximeter • Pulse oximetry provides estimates of arterial oxyhemoglobin saturation (SaO2) by utilizing selected wavelengths of light to noninvasively determine the saturation of oxyhemoglobin (SpO2) • Nonin OEM II module • RS232-connection • Bluetooth connection Finger clip http://www.adinstruments.com/products/list.php?group=Transducers*and*Accessories&sectionurl=Pulse*Oximetry&testgroup=N

  8. Existing Devices: Pulse Oximeter Rest 75 measurements per second Movement

  9. Combining Diagnostics • ECG • Stethoscope • Pulse oximeter Will give real-time feedback on • Heart condition Valve operation Chamber contraction • Blood oxygenation

  10. Prof. Singer Contacted the Mathematics Group to Initiate a Research Programme in Vascular Mechanisms. From an instrumentation basis the questions was asked What type of measurements are being made What is required What type of instrument is used Do we have the relevant expertise Could a low cost portable diagnostic instrument with suitable resolution be developed and Would it have value.

  11. Microcirculation Capillaroscopy Microcirculation • Microcirculation plays a key role in tissue oxygenation • Red blood cell (RBC) is the indicator of the oxygen delivery. It is widely used in clinical studies Capillaroscopy • for analysing images of the microcirculation using spectrophotometry in order to compute a complete blood count (CBC) without removing blood from the body[1] • Orthogonal polarization spectral (OPS) imaging • Sidestream dark-field (SDF) imaging 2009-2010 ES9P5 Remote Sensing and Data Processing Presentation

  12. OPS imaging Orthogonal Polarization Spectral (OPS) imaging [2] Cytocan-II by Cytometrics (1) Polarized light (548nm) (2) Depolarized scattered light (3) CCD camera (4) Reflected polarized light is eliminated Cytocan-II 2009-2010 ES9P5 Remote Sensing and Data Processing Presentation

  13. OPS imaging Advantages • Better clarity (than conventional reflectance imaging) • Light wavelength (600–1100 nm) reduces scattering • and absorption for tissues • Clinical validated Disadvantages • Illumination scattering, blurring • Contrast from reflected light • Resolution 2009-2010 ES9P5 Remote Sensing and Data Processing Presentation

  14. SDF imaging Sidestream Dark-field (SDF) imaging[3] MicroScan Video Microscope by MicroVision Medical LEDs: 540±50 nm Vessels can be seen only if they contain RBCs, which appear dark 2009-2010 ES9P5 Remote Sensing and Data Processing Presentation

  15. SDF imaging Advantages • Better clarity, sensitivity and resolution (than OPS) • Fine-tune the depth of focus without moving the probe, thus without blurring • portable operation • Clinical validated Disadvantages • Video frame rates at 750 pixels/sec (25 fps (PAL) or 30 fps (NTSC)) • Resolution 2009-2010 ES9P5 Remote Sensing and Data Processing Presentation

  16. Video output was visualized on a monitor and connected to a computer via a signal converter (Canopus, ADVC110) to directly and digitally record images onto a hard drive as DV-AVI files to enable off-line analysis of the images.[4] majority capillaries size (10 to 35 μm) 10 microns = 50lp/mm (line pairs per millimetre) resolution 2009-2010 ES9P5 Remote Sensing and Data Processing Presentation

  17. RBC Velocity Determination • image registration and pre-processing • skeleton extraction • sketch the skeleton to estimate horizontal and vertical displacements • velocity of all the pixels 2009-2010 ES9P5 Remote Sensing and Data Processing Presentation

  18. RBC Velocity Determination • A 45-second video of capillary blood flow • 1350 continuous frames (30 fps) • The RBC velocity of 12 vessels (at 3 sites) • Microcirculatory Analysis Software (MAS 2.0) • microcirculatory blood vessel diameters • RBC kinetics (Academic Medical Centre, University of Amsterdam). 2009-2010 ES9P5 Remote Sensing and Data Processing Presentation

  19. Conclusion • Available instrumentation exists which has adequate resolution However, • There is the potential to create a low cost portable instrument. • There is the potential to create a high resolution portable system • The resolution and design closely matches that developed for the digital ophthalmoscope. • The processing applied closely matches that used for processing aerodynamic research currently in progress • The Resolution and frame rate could be improved significantly • Advanced computer-aided image processing tools are avaiable • CMOS cameras to improve power consumption and resolution 2009-2010 ES9P5 Remote Sensing and Data Processing Presentation

  20. References • [1] NADEAU RG, GRONER W: Orthogonal polarization spectral imaging: State of the Art. In: Orthogonal Polarization Spectral Imaging. MESSMER K (ed). Karger, Basel, Vol 24, pp 9-20. (2000) • [2] Černý, V. TUREK, Z. PAŘÍZKOVÁ, R. Orthogonal Polarization Spectral Imaging. Physiological Research. Minireview. 56: p141-147, (2007). • [3] Ince C. Sidestream dark field imaging: an improved technique to observe sublingual microcirculation.Critical Care 9 (Suppl 1): P72, (2005). • [4]Goedhart PT, Khalilzada M, Bezemer R, Merza J, Ince C. Sidestream Dark Field (SDF) imaging: a novel stroboscopic LED ring– based imaging modality for clinical assessment of the microcirculation. Optics Express;15:15101-14. (2007). • [5]Leahy, M, J. et al. Biophotonic methods in microcirculation imaging. Medical Laser Application, 22-2, p 105-126. (2007). 2009-2010 ES9P5 Remote Sensing and Data Processing Presentation

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