DTI Research Projects in Image-Guided Therapy
Lauren O’Donnell
SFN Chicago Oct. 09 Defining Spatial Relationships Between fMRI and Fiber Tracts
Neurosurgical Planning for White Matter
• Tumor mass effect displaces– Gray matter (GM)– White matter (WM)
• Tracts are not visible during surgery– Electrocortical stimulation for GM not WM
• Healthy WM and tumor may have same “jello-like” consistency
• To preserve function– Avoid crucial tracts– Incision and trajectory planning
• Challenges in DTI Tractography for IGT– Displacement complicates tract
selection/identification– Edema may interrupt tract tracing– Anatomy not completely traced by single tensor
Fiducial Tractography: Slicer• Fiducial:
– Movable seed point
• Interactive Probing of Fiber Bundles– Peritumoral
Fibers
• fMRI Display in Context with Structural and Diffusion Volumes
Image by JJ. Lemaire. Fiducial Tractography by A. Yarmarkovitch
Slide courtesy R. Kikinis
Open IGT Link: Slicer3 in OR• December 2007: Concept• January 2008: Prototype and
Name• July 2008: BrainLab VVLink
with Yale (Papademetrios)• December 2008: Real Time
MR Control• February 11, 2009: Initial
Clinical Application with Dr. Alex Golby
• Multi-Site Collaboration coordinated by NCIGT (Jolesz, Hata et al)
Golby, Hata, Liu, Tokada, Ibanez, Papademetrios
Slide courtesy R. Kikinis
2-Tensor Tractography• Crossing fibers exist
– i.e. Corpus callosum connects to frontal/temporal/parietal/occipital
• Peled’s model: 2 tensors in a plane– Resolving crossings in the corticospinal tract
by two-tensor streamline tractography: Method and clinical assessment using fMRI. Arish A. Qazi, Alireza Radmanesh, Lauren O'Donnell, Gordon Kindlmann, Sharon Peled, Stephen Whalen, Carl-Fredrik Westin and Alexandra J. Golby. NeuroImage 47(supplement 2):T98-T106, 2009
• Kalman filtered tractography– James Malcolm and
Yogesh Rathi (BWH)– Python implementation
project this week
O’Donnell et. al. Defining Spatial Relationships Between fMRI and Fiber Tracts. MICCAI Diffusion Workshop 2009
DTI+fMRI Atlas Project: Identify displaced tracts
• Proposed model• fMRI-fiber distances
O’Donnell et. al. Defining Spatial Relationships Between fMRI and Fiber Tracts. MICCAI Diffusion Workshop 2009
DTI+fMRI Atlas Project: Leave-One-Out Model Predictions
