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Proceedings Paper

ROC-based determination of the number of clusters for fMRI activation detection
Author(s): Hesamoddin Jahanian; Hamid Soltanian-Zadeh; Gholam Ali Hossein-Zadeh; Mohammad-Reza Siadat
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Paper Abstract

Fuzzy C-means (FCM), in spite of its potent advantages in exploratory analyze of functional magnetic resonance imaging (fMRI), suffers from limitations such as a priori determination of number of clusters, unknown statistical significance for the results, and instability of the results when it is applied on raw fMRI time series. Choosing different number of clusters, or thresholding the membership degree at different levels, lead to considerably different activation maps. However, research work for finding a standard index to determine the number of clusters has not yet succeeded. Using randomization, we developed a method to control false positive rate in FCM, which gives a meaningful statistical significance to the results. Making use of this novel method and an ROC-based cluster validity measure, we determined the optimal number of clusters. In this study, we applied the FCM on a feature space that takes the variability of hemodynamic response function into account (HRF-based feature space). The proposed method found the accurate number of clusters in simulated fMRI data. In addition, the proposed method generated excellent results for experimental fMRI data and showed a good reproducibility for determining the number of clusters.

Paper Details

Date Published: 12 May 2004
PDF: 10 pages
Proc. SPIE 5370, Medical Imaging 2004: Image Processing, (12 May 2004); doi: 10.1117/12.535691
Show Author Affiliations
Hesamoddin Jahanian, Univ. of Tehran (Iran)
Institute for Studies in Theoretical Physics and Mathematics (Iran)
Hamid Soltanian-Zadeh, Univ. of Tehran (Iran)
Institute for Studies in Theoretical Physics and Mathematics (Iran)
Henry Ford Health System (United States)
Gholam Ali Hossein-Zadeh, Univ. of Tehran (Iran)
Mohammad-Reza Siadat, Henry Ford Health System (United States)
Wayne State Univ. (United States)

Published in SPIE Proceedings Vol. 5370:
Medical Imaging 2004: Image Processing
J. Michael Fitzpatrick; Milan Sonka, Editor(s)

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