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DTI Research Projects in Image-Guided Therapy. Lauren O’Donnell. 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
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DTI Research Projects in Image-Guided Therapy Lauren O’Donnell
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 Defining Spatial Relationships Between fMRI and Fiber Tracts
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
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 O’Donnell et. al. Defining Spatial Relationships Between fMRI and Fiber Tracts. MICCAI Diffusion Workshop 2009