Fiber Tracking Techniques in
Magnetic Resonance Diffusion
Tensor Imaging
Grace Michaels
CSUN, Computer Science
Junior
What is MRDTI ?
• A modern technique for visualization at high
resolution of the white matter tracts in the brain.
Two Steps…
MRI scanner, determines the
orientation of the tracts at each
point by measuring diffusion rates
and identifying the direction of
the fastest diffusion.
The information about the
diffusion rates is encoded into the
diffusion tensor and various
integration techniques are used to
reconstruct the path of the fiber.
DT-MRI also promises to
further our understanding of
abnormalities in a variety of
diseases such as
• Stroke
• Tumors
• Multiple sclerosis
• Schizophrenia
Experiments
• 2D
• 3D
Experiments
• 2D
Experiments
• 2D
Experiments
• 2D
How the method works?
• We start from initial
concentration of test
liquid, corresponding
to a drop at some point
of the tested media.
How the method works?
• The fact that water molecules are more
likely to propagate along the fiber then
cross it is reflected in the coefficients of
diffusion tensor prescribing different rates
of propagation in different directions trough
the linear diffusion equation.
Diffusion Tensor
So, we solve the anisotropic
equation:
3
3
d
d
d
 ( x, t )   Tij
 ( x, t )
dt
dx j
i 1 j 1 dxi
where  ( x, t ) is concentration of test molecules at point x   3
- one step forward in time
- one step backward in time
A curvature-based ridge-tracking
algorithm
in 2D
Finding end points
Finding end points
Why is fiber tracking important?
• Brain surgery may cause damage to
important fiber bundles. Knowledge of their
extension could minimize functional damage
to the patient.
• White matter can be visualized using fiber
traces for a better understanding of brain
anatomy.
• Connectivity between different parts of the
brain can be inferred, which is useful for
functional and morphological research on the
brain.
Future work
• Develop 3D experiments
• Get real data from MRI clinic in Pasadena
• Real data experiments
Acknowledgements
• Dr. Alexander Alekseenko, Math
Department, CSUN
• NASA CSUN/JPL PAIR Program
• Dr. Carol Shubin, NASA CSUN/JPL PAIR
Program director, Math Department
THANK YOU!
QUESTIONS ???