Program Information
Use of Fiber Tracking to Estimate the Directions of Cancer Recurrence in Patients with Glioblastoma: A Feasibility Study
Y Valenciaga1*, L Claps2 , J Knisely1 , P Kingsley1 , B Zhang1 , A Kapur1 , (1) Northwell Health, Lake Success, NY, (2) Hofstra University,Long Island, NY
Presentations
TU-RPM-GePD-J(A)-4 (Tuesday, August 1, 2017) 3:45 PM - 4:15 PM Room: Joint Imaging-Therapy ePoster Lounge - A
Purpose: Glioblastoma (GBM) is an aggressive brain tumor with a tendency for recurrence. Most GBM patients recur within the first treated site. During target delineation, the planning target volume is drawn with a 2-cm isotropic expansion of the gross-tumor-volume (GTV) using T2-weighted or T1-weighted, contrast-enhanced MR images. Previous studies have shown that GBM infiltrates along white matter tracts. DTI is an MR-based imaging technique that detects the magnitude and direction of diffusion of water, which is influenced by white matter tracts. The goal of this study is to find a correlation of tracts crossing the original target volume and the sites of recurrence. This will potentially reduce the size of the target volume. Instead of adding a 2-cm isotropic margin, some healthy tissue remote from fiber tracts crossing the GTV could be spared.
Methods: The criteria for this study: 1) patients who have recurred with GBM, 2) were treated with RT, and 3) whose DTI were obtained prior to first RT treatment. iPlan (Brainlab, Germany) was used to obtain fiber bundles that pass through the GTV by specifying the values of fractional anisotropy and fiber minimum length. Eddy current correction was applied to the DTI to reduce artifacts and improve registration.
Results: Data from three patients was analyzed. In patients A and B, fibers were found connecting the original disease site and the recurrence site when using FA values in the range 0.2 to 0.4. In patient C, few fibers were crossing the original GTV and none of them reached the recurrence site, which was remote from the original site.
Conclusion: This work shows preliminary results on using DTI imaging features to assess the direction of GBM recurrence. The values of anisotropy were not predictive enough for this small sample size. The future work will be to include more patients.
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