The Forward Scanning – Contagious Voxel Algorithm: A 3D Connected Components Algorithm

Khalid J. Oweis, Madison M. Berl, Elizabeth S. Duke, Kaitlin Blackstone, Murray H. Loew, William D. Gaillard, Jason M. Zara


Quantitative tools are needed to characterize active clusters in three-dimensional brain activity maps that result from statistical parametric mapping of fMRI time-series images. Extracting volumetric features contributes unique quantitative information not yet available with existing software packages. In this work, we present an algorithm that counts clusters and assigns each a numerical identifier. The results of this algorithm were then used to calculate various volumetric features. This algorithm was developed using MATLAB and applied to three regions of interest (ROI) and their homologues: The Left Inferior Frontal Gyrus (LIFG), the Right Inferior Frontal Gyrus (RIFG), the Left Middle Frontal Gyrus (LMFG), the Right Middle Frontal Gyrus (RMFG), the Left Superior Temporal Gyrus defined by Brodmann’s areas 21, 22 and 39 (Left Wernicke’s area) and Right homologue to Wernicke’s area. These regions process distinct expressive and receptive aspects of language. This algorithm shows robustness and scalability to regions of different shapes and sizes.


The forward Scanning, Contagious Voxel algorithm, A 3D Connected Components Algorithm.

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