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Abstract #2846

Consistent Activation Across Trials and Field Strengths by ROC-Reproducibility Thresholding

Tynan Reid Stevens1, David B. Clarke2, Ryan CN D'Arcy1, Steven D. Beyea1

1IBD-Atlantic, NRC, Halifax, Nova Scotia, Canada; 2QEII Health Science Centre, Halifax, Nova Scotia, Canada

Setting activation thresholds remains a significant challenge in fMRI. Fixed threshold levels do not account for individual variability, habituation, or acquisition strategies. We developed a method for determining data-driven thresholds levels based on test-retest ROC-reproducibility (ROC-r) analysis. Eight subjects performed test-retest fMRI at two field strengths (1.5 & 4 Tesla). Optimized ROC-r thresholds were calculated for the template (5.27 +/- 0.22) and retest images (3.71 +/- 0.18). The ROC-r thresholds were significantly higher for 4 Tesla than 1.5 Tesla. Compared to FDR or Bonferroni thresholds, ROC-r thresholds produced more consistent activation extent across field strengths and trials.