Stereotactic Device for MRI

1
Stereotactic Device for MRI Team Members Jeremy
Glynn, Jeremy Schaefer, Mike Conrardy, Adam
Goon Client Ian Rowland, PhD Advisor Prof.
William L. Murphy
Client Requirements
Testing
Abstract
Ian Rowland, who performs regular imaging of
rodents at the UW Hospital as part of his
research, requested a stereotactic device that
minimizes the movement of the rat while being
imaged. The ideal design would also incorporate a
heating device to warm the rat to prevent
hypothermia and be able to provide the rat with
the proper anesthesia. Our prototype is able to
effectively restrain and align the animal for
optimal imaging, delivers the necessary
anesthetic, and includes a design for heating.

• Cannot interfere with imaging device (MRI
  compatible)
• Fit inside rat MRI coil (63 mm diameter)
• Brain centrally aligned down axis of MRI
• Anesthetic mask able to cover animals nose
• Complete restraint of animals head
• Withstand 4.7 Tesla magnetic field
• Heating device to warm animal
• Maintain body temperature within 5o of 37oC
• Adjustable to accommodate various sized rats

Figure 2 Poor image resulting from improper
alignment.
Figure 3 Properly aligned image acquired using
our prototype.,
MRI imaging done on rats is commonly used in
neurological research. In order for the images to
achieve high resolution and be valuable in
research, it is crucial that the rat is
well-restrained, the brain is centrally oriented
within the coil, and the animal is kept warm
while anesthetized.
Final Design

• Our design was implemented in the labs imaging
  procedure. Key improvements resulting from our
  design included
• Rat was well-restrained, reducing motion
  artifacts
• Brain was properly aligned in all planes within
  the coil, producing level images.
• Proper alignment also decreased calibration time
• Anesthetic was appropriately delivered to the
  animal

Tooth Bar Hooks around rats teeth, then slides
back and fastens to secure rat.
Anesthetic Assembly Slides along track and
features removable mask for easier access to rat.
Motivation
Ear Pegs Keep rats head level and secure,
adjustable for various size rats.

• Problems with the current system include
• Restraining Method Tape
• Does not adequately secure the animal
• Makes proper brain alignment difficult
• Heating Method Circulating Hot Air
• Heats the imaging coil, decreasing the
  signal-to- noise ratio (quality).
• Air flow blows anesthetic away from subjects
  mouth.

Budget

• Small Animal Heating Pad - 51.00
• HTP-1500 Circulator - 385.00
• Plastic Materials and Adhesive - 304.88
• Total - 740.88

Polycarbonate Cradle Inserted into MRI coil,
can adjust height for proper alignment.
Heating Pad Uses circulating warm water to keep
rat warm while anesthetized.
Future Work

• Provide replacement pieces
• Replace hex screws with thumbscrews
• Run longer duration scans utilizing heating
  device

Tube to Anesthetic System
References
1 Benveniste, H. Blackband, S. (August 2002).
MR microscopy and high resolution small animal
MRI applications in neuroscience research.
Progress in Neurobiology, 67(5), 393-420.  2
Imaging Technology Group (2005).
Three-Dimensional Printing Z406. Beckman
Institute for Advanced Science and Technology at
the University of Illinois. Retrieved 1 March
2008. 3 Serway, R. Jewett, J. (2004).
Physics for Scientists and Engineers (6th ed.).
Belmont, CA Thomson.  4 Residential Hot Water
Floor Heat Design and Installation Guide.
Infloor Heating Systems. Retrieved 28 February
2008. lthttp//www.infloor.com/pdfs/Infloor_residen
tial_guide.pdfgt. 5 Taylor, et al. (2007).
Study of two devices used to maintain
normothermia in rats and mice during general
anesthesia. Journal of the American Association
for Laboratory Animal Science . 465 , pg. 37
-41. 6 Sikoski et al. (2007). Comparison of
heating devices for maintaining body temperature
in anesthetized laboratory rabbits (Oryctolagus
cuniculus). Journal of the American Association
for Laboratory Animal Science. 463, pg61 -63.
HTP-1500 Heats and circulates water to the
heating pad with /- 1oF accuracy.
Figure 1 Rat and cradle being inserted into the
MRI coil using the current restraint methods.
Rat positioned in restraint