Automating the Sciatic Function Index Data Collection Process

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Automating theSciatic Function IndexData
Collection Process

• Progress Report
• Group 33
• October 29, 2007
• Presenter Dave Working

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Group Structure

• Dave Working
• Kyle Mairose
• Kenny Dike
• Mentor Matt Wood
• For Use in Dr. Sakiyama-Elberts Lab

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Overview

• Background
• The Sciatic Function Index (SFI)
• SFI Acquisition Methods
• Current method for obtaining SFI in Dr.
  Sakiyama-Elberts lab
• Other methods
• Desired method and design requirements
• Design Alternatives
• Motion vs. Still
• Image Acquisition
• Software Options
• Design Specs
• Device Construction
• Recording Method
• Software Outline
• Schedule, Responsibilities, References

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Background The SFI

• Nerve crush injuries studied in sciatic nerve in
  rats
• Number of nerve connections ? functional ability
• Need functional test to quantify nerve
  regeneration
• Easiest test walking
• How do we measure a rats normal walking
  ability?
• Sciatic Function Index (SFI) developed as a way
  to quantify how well the sciatic nerve has
  regenerated functional ability
• Uses toe spreads and constants developed by
  independent testing

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Background the SFI
Toe spread factor (TSF) (ETS-NTS)/NTS
Intermediate TSF (ITSF) (EITS-NITS)/NITS
Print length factor (PLF) (EPL-NPL)/NPL SFI
(-38.3 x PLF) (109.5 x TSF) (13.3 x ITSF)
-8.8
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Current Acquisition Method

• Ink and Paper Method
• Paint the rats feet
• Walk along paper
• Scan paper into computer
• Use software to pick out points on footprints
• Software calculates SFI
• Cons
• Time-consuming
• Messy
• Smudges create inaccuracy

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Other Methods

• Pressure Sensors
• Electric resistance changes depending on
  pressure
• Accurate-- but 9,000 apiece
• Digital Image Capture
• Clean, easy to use, not too expensive
• Very accurate

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Other Methods
?
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Design Requirements

• Cut down on time and mess
• Device framework
• Transportable
• Able to support and allow a full-grown rat to
  walk
• Camera
• Fast enough sampling rate to capture image of
  footprint
• Good enough resolution to distinguish separate
  toes on paw print
• Develop software to automate image analysis
• Frame-grabbing
• Point selection
• Budget 1,000 to 2,000

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Design AlternativesImage Acquisition

• Camcorder
• Not difficult to use
• Harder to mount
• Cost 500
• Faster fps
• Much better resolution
• More memory

• Camera
• Easy to use
• Easy to mount on rat walking structure
• Cost 200
• Slower fps
• Lower resolution
• Less memory

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Design AlternativesImage Acquisition
Camera vs. Camcorder Summary
?
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Design AlternativesCamcorder Placement

• Underneath, fixed

Front, fixed, with mirrors
Underneath, moving
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Design AlternativesCamcorder Placement
Placement Summary
?
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Design Alternatives Software

• Software needs to be able to
• Separate the footprint from the rest of the image
  (Separation)
• Take video frames and grab images that have full
  foot contact with walkway (Frame Grabbing)
• Pick out points on foot in order to calculate SFI
  (Point Picking)
• Calculate SFI according to formula (Calculation)

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Design Alternatives Software

• Frame Grabbing
• Outside software available for frame-grabbing
• However, all require manual operation
• Point Picking
• Moran and Sakiyama-Elbert labs both use MATLAB
  implementation
• Requires manual operation
• Novel approach required to automate

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Design Specs Hardware
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Design Specs Hardware

• Panasonic PV-GS320
• MiniDV movie recording format
• 2048 x 1512 pixels resolution
• Manual Focus
• 60 min. recording time
• USB port

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Design Specs Software

• Separation
• MATLAB Image Acquisition Toolbox imports movie
  from camera into MATLAB
• MATLAB Image Processing Toolbox
• Enhancement increase contrast of image
• Segmentation edge detection using Marr-Hildreth
  method
• Frame Grabbing
• MATLAB Image Processing Toolbox
• Compare subsequent processed images by area of
  foot
• Biggest area corresponds to full contact with
  walkway
• Compare pixel counts

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Design Specs Software

• Point Picking
• MATLAB Image Processing Toolbox
• Hit-or-miss transforms
• Shape estimation
• Difficult!
• Calculation
• MATLAB
• Input values as determined by point picking into
  SFI formula

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Schedule

• 6.2 Responsibilities

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Responsibilities

• Kenny Structural design, CAD drawings,
  Preliminary Presentation
• Kyle Image processing software development,
  Final Presentation
• Dave Project administrator, Website design,
  progress reports, image processing software
  development, Progress Presentation

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References
Bain JR, Mackinnon SE, Hunter DA. Functional
evaluation of complete sciatic, peroneal and
posterior tibial nerve lesions in the rat. Plast
Reconstr Surg 83 (1989) 129-36. De Medinaceli
L, Freed WJ, Wyatt RJ. An index of the functional
condition of rat sciatic nerve based on
measurements made from walking tracks. Exp.
Neurol. 77 (1982) 634-643. Dijkstra JR, Meek
MF, Robinson PH, Gramsbergen A. Methods to
evaluate functional nerve recovery in adult rats
walking track analysis, video analysis and the
withdrawal reflex. Journal of Neuroscience
Methods 96 (2000) 89-96. Inserra MM, Bloch DA,
Terris DJ. Functional indices for sciatic,
peroneal, and posterior tibial nerve lesions in
the mouse. Microsurgery 182 (Dec 1998) 119-124.
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References (Continued)
Luis AL, et. al. Long-term functional and
morphological assessment of a standardized rat
sciatic nerve crush injury with a non-serrated
clamp. Journal of Neuroscience Methods 163
(2007) 92-104. Nichols CM, et. al. Choosing the
correct functional assay A comprehensive
assessment of functional tests in the rat.
Behavioural Brain Research 163 (2005)
143-158. Walker JL, et. al. Gait-stance duration
as a measure of injury and recovery in the rat
sciatic nerve model. Journal of Neuroscience
Methods 52 (1994) 47-52. Varejao A, et al.
Methods for the experimental functional
assessment of rat sciatic nerve regeneration.
Neurological Research 26 (2004 Mar).
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Questions?