A quantitative comparison of functional MRI cluster analysis.
The aim of this work is to compare the efficiency and power of several cluster analysis techniques on fully artificial (mathematical) and synthesized (hybrid) functional magnetic resonance imaging (fMRI) data sets. The clustering algorithms used are hierarchical, crisp (neural gas, self-organizing maps, hard competitive learning, k-means, maximin-distance, CLARA) and fuzzy (c-means, fuzzy competitive learning). To compare these methods we use two performance measures, namely the correlation coefficient and the weighted Jaccard coefficient (wJC). Both performance coefficients (PCs) clearly show that the neural gas and the k-means algorithm perform significantly better than all the other methods using our setup. For the hierarchical methods the ward linkage algorithm performs best under our simulation design. In conclusion, the neural gas method seems to be the best choice for fMRI cluster analysis, given its correct classification of activated pixels (true positives (TPs)) whilst minimizing the misclassification of inactivated pixels (false positives (FPs)), and in the stability of the results achieved.
Dimitriadou
Evgenia
E
Institut für Statistik und Wahrscheinlichkeitstheorie, Technische Universität Wien, Vienna, Austria. dimi@ci.tuwien.ac.at
Barth
Markus
M
Windischberger
Christian
C
Hornik
Kurt
K
Moser
Ewald
E
D000465:Algorithms; D001931:Brain Mapping; D016000:Cluster Analysis; D006801:Humans; D008279:Magnetic Resonance Imaging