Muscle Volume Analysis 3D reconstruction allows for accurate volume calculation
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Transcript of Muscle Volume Analysis 3D reconstruction allows for accurate volume calculation
• Muscle Volume Analysis• 3D reconstruction allows for accurate volume calculation
• Provides methods for monitoring disease progression• Measure muscle atrophy over extended periods of time
• Aid in preventive and therapeutic disease research• Low cost allows for daily use• MRI too expensive for research purpose
DESIGN PERFORMANCE AND SUCCESSDESIGN COMPONENTSINTRODUCTION• Amyotrophic Lateral Sclerosis (ALS) is a progressive
neurodegenerative disease that causes atrophy of voluntary muscles through degradation of motor neurons
• Size and shape of muscles like the bicep are good indicators of the severity of the disease
APPLICATIONS
DESIGN CRITERIA
Tracking System:• Provide linear location on a 3-D coordinate system at each
acquisition point• Provide angular orientation at each acquisition point
• Roll, pitch, and yaw• Have an acquisition rate that matches the US acquisition
rate• Have error that is less than or equal to the error from the
US machine3-D Reconstruction Software:• Translate slice location to patient location• Rotate the image according to the angular data• Recognize muscle tissue• Compute muscle volume
SYSTEM VERIFICATION
FUTURE DIRECTIONS
• Construct a stable attachment device to connect the position sensors and the US probe
• Design a more efficient infrared LED arrangement for position tracking of US probe
• Explore different methods of obtaining x, y and z position of US probe to increase accuracy• Use of other accelerometers and gyroscopes
• Streamline software for a more user friendly data analysis• Determine methods to reduce effects of sensor drift• Devise a more accurate scaling for Wii-Motion+ output
ACKNOWLEDGEMENTS
Special Thanks to our advisor Dr. Christopher Lee M.D. of the Vanderbilt Department of Neurology, Dr. Paul King, graduate student advisor Alex Makowski, VUMC for the use of a Sonosite Titan, Nintendo, Jordan Brindza and Jessica Szweda of Notre Dame for the WiiLAB software package and manuals, and Knuckles904 for help with the Wii-Motion+ Arduino code.
Figure 4. The Arduino prototype board
Figure 9. Position and angle data for each acquisition slice for both systems. LED System (Left). LED + Wii MotionPlus System (Right)
• Magnetic Resonance Imaging (MRI) is the gold standard for muscle imaging, but is expensive and immobile
• Ultrasound (US) imaging gives comparable 2D images, is cheaper, mobile, and has shorter acquisition times
Wii System Components to Track Ultrasound Probe and Create 3-D ImagesWii System Components to Track Ultrasound Probe and Create 3-D Images Van Gambrell, Laura Owen, Steven Walston, Jonathan WhitfieldVan Gambrell, Laura Owen, Steven Walston, Jonathan Whitfield
Advisor: Dr. Christopher Lee M.DAdvisor: Dr. Christopher Lee M.D..
Figure 1. Diagram of normal and ALS affected muscle and neural system
Figure 7. Linear error from LED system
•Tested by moving source on a fixed path with known distance•Compared measurements with returned data
•Created a phantom for volume accuracy•To compare US and MRI
•Linear error is greater than that of the ultrasound system•US system error is within 3 percent compared to 22, 31, and 2 percent
•System failed accuracy verification
Figure 8. Drift from Wii Motion+ with movement only from 17-27 seconds
•External IR interference negatively affected ability to accurately track LEDs•Reconstruction Software:•Resolution reduced from 640x480 to 160x120 in order to function within memory constraints of MATLAB
•Scans limited to less than 15sec due to Wii-Motion+ sensor drift• Angle and position data filtered due to significant noise
Figure 2. MRI slices used to create 3-D muscle image
Figure 3. Ultrasound images used to approximate 3-D muscle image
•Wii-mote•Infrared camera capable of tracking 4 infrared (IR) light sources•Bluetooth data transmission
•Wii-Motion+•Provides yaw, pitch and roll info
•Arduino Prototype board•Interfaces between Wii-Motion+ and MATLAB to acquire yaw, pitch, roll
•Sonosite Titan •Small portable Ultrasound machine•2D Linear array transducer
•Design Function•Two Wii-motes are placed in a known location and orientation
• Used to calculate the position of the US probe in 3-D space
•Wii-Motion+ provides rate of change in yaw, pitch and roll
•Integrated to provide the angular orientation of the ultrasound probe
•IR LEDs were tested as a redundant source of yaw, pitch and roll angular data•Each acquired US image is assigned a x, y, and z position and a yaw, pitch and roll angle from the Wii-motes and Wii-Motion+
•3-D Reconstruction Software•Takes position data and realigns slices in new matrix representing scanned area•Uses angle data to rotate slice appropriately•Done through post processing
Figure 5. Arduino with LED + Wii MotionPlus attached to US probe
Figure 6. LED+WiiMotionPlus System with Sonosite Titan