Infrared Camera from Wii System to Track Ultrasound Probe and Create 3-D Image Vanderbilt University Department of Biomedical Engineering   Van Gambrell Laura Owen Steven Walston Jonathan Whitfield Advisor Dr. Christopher Lee - Department of Neurology

Amyotrophic Lateral Sclerosis ALS is a progressive neurodegenerative disease that causes atrophy of voluntary muscles through degradation of motor neurons   The size, shape, and structural makeup of muscles like the bicep can be good indicators of the severity of the disease

ALS in the United States 20-30 thousand people in the US have ALS Doctors diagnose approximately 5,000 new cases every year. Once diagnosed, a person with ALS is only expected to live 3-5 years. Understanding the effects of the disease should help increase the life expectancy and in time hopefully cure it Stephen Hawking

Dr. Christopher Lee Vanderbilt University Medical Center, Neurology Department  Dr. Lee specializes in evaluating muscle ultrasound in ALS patients He uses this information to determine early clinical and electrodiagnostic features of critical illness polyneuropathy and myopathy

Imaging Muscles MRI Ultrasound MRI Great images But expensive, time consuming, and immobile Current standard Ultrasound Images comparable to MRI Cheaper Short imaging time 2D linear images acquired by free hand Difficult to make a reproducible 3D image  Ultrasound With an MRI you get a perfect 360 view of slices so makes an accurate 3-d model -However Ultrasound is less methodical and leaves room for gaps in measuring data.  which would prevent the 3-D model from being fully representative.

Imaging Machinery Ultrasound MRI Cost: Sonosite Titan: $16,500 Size: Small laptop 8" LCD Mobile: Portable docking station 4 hour battery life Cost: Typical MRI Machine: $3 Million Size: 490 Square Feet Mobile: Not Mobile MRI machine 7 feet by 7 feet by 10 feet MRI Cost : ~$3 million Sonosite Titan: $16,500 Size of a small laptop Comes with a portable docking station small with an 8" LCD has a 4 hour battery life laura

Could 3-D Ultrasound be a good alternative to MRI Can the location and position of the ultrasound probe be monitored? Can a three dimensional image of muscle be generated using the signal from the probe and correlating it with the data of the orientation of the US probe? Will an imaging system that fulfills these two questions be effective, portable, and cost efficient? Will the monitoring of muscle volume be effective in researching treatments for ALS? - Accurate     -Free Hand Sensitivity -Comparable to MRI -If the machine cant fulfill these requirements then there is no need for the machine, because MRI will produce better results laura The main goal of this project is to create a way to monitor the muscle atrophy.  

Solution Design Objective is to use 2 Wii-mote CCD's to track infrared LEDs x and y position from each wii mote to calculate position in 3D Using a triangulation algorithm to determine the position of the LED in 3 dimensional space using the 2 Wii-motes   Wii-mote can track up to four infrared emitters at one time Placement of the LEDs will allow the tracking of the probe in  3-D space Using the gyroscope from the Wii Motion Plus we will be able obtain the yaw, pitch, and roll information of the US probe jon

Status and Results Wiimote simultaneously tracks 4 infrared LEDs in 2D space  Wrote a triangulation algorithm that computes 3D location from the 2 sets of data Determined the camera calibration information, including focal length and other matrix information Calculated a centroid to return one data set for 4 IR light sources Ordered the WiiMotion Plus, Andruino, and adapter Have Opensource code to return the Yaw, Pitch and Roll data from the WM+ and Andruino Determined sampling rate to be 60 Hz jon

Data Transfer Schematic jon

Wii-Motion Plus and Arduino Wii-Motion Plus has much more sensitive accelerometers than the wii mote that can provide 6 degrees of freedom to correctly establish the U.S. probe's orientation. jon Arduino is an open source prototyping platform that can interface with the Wii-Motion Plus and the computer to provide angular data from the U.S. probe

Physical Schematic Determined the asymmetrical arrangements of infrared light to be placed on the US probe Determined that one WiiMote Camera should have a field of view perpendicular to the typical orientation of the US probe The backbone of the triangulation algorithm has been determined The orientation of the two motes can be used in unison with the distance between the two returned data points. This relation can determine the third z coordinate using simple trigonometry Determined the camera calibration information, including focal length and other matrix information Calculated a centroid to return one data set for 4 IF lights

Estimated Final Cost of Design Wii Motes: $39.99  X 2 = $79.98 Wii Motion Plus: $17.96 Adruino: $30.00 Adruino + Wii Motion Plus Adapter: $4.00 Circuit Electronics: $15 LEDs, Resistors, Battery, Wires System Mount: ~$20.00 Arm Stabilizer: ~$18.00 Unforeseen Additions: ~$40.00 Final Cost: ~$225.00 laura

Known Problems Infrared signals from external sources can interfere with LED signals The IR LEDs emit signal in a conical area (limited view) Potential accuracy problems Incorrect centroid calculations due to blocked IR LED   steven

Wiimote Sensitivity 2 infrared LEDs 30.48cm apart Error = -2.46mm ± 2.23 (mean ± std)  steven

Current Work Plans Set up the Wii Motion Plus + Adruino Use the Opensource Software to obtain working gyroscope data   Sync wiimote and ultrasound acquisition rates Interface the system with the 3-D reconstruction software steven

Future Work Plans By March 1st Physically attach the WiiMotion+ device to US probe Create a mounting system for the IR cameras  Use the position data to tag Ultrasound images and create a 3 dimensional image  Mid March Begin taking samples for data analysis April Have completed data acquisition Quality assessment steven