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Proceedings Paper

Activation detection in fMRI data via multiscale singularity detection
Author(s): Ralf Mekle; Andrew F. Laine; Gerard Mark Perera; Robert DeLaPaz
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Paper Abstract

Detection of active areas in the brain by functional magnetic resonance imaging (fMRI) is a challenging problem in medical imaging. Moreover, determining the onset and end of activation signal at specific locations in 3-space can determined networks of temporal relationships required for brain mapping. We introduce a method for activation detection in fMRI data via wavelet analysis of singular features. We pose the problem of determining activated areas as singularity detection in the temporal domain. Overcomplete wavelet expansion at integer scales are used to trace wavelet modulus maxima across scales to construct maxima lines. Form these maxima lines, singularities in the signal are located corresponding to the onset and end of an activation signal. We present result for simulated phantom waveforms and clinical fMRI dat from human finger tapping experiments. Different levels of noise were added to two waveforms of phantom data. No assumptions about specific frequency and amplitude of an activation signal were made prior to analysis. Detection was reliable for modest levels of random noise, but less precise at higher levels. For clinical fMRI data, activation maps were comparable to those of existing standard techniques.

Paper Details

Date Published: 4 December 2000
PDF: 11 pages
Proc. SPIE 4119, Wavelet Applications in Signal and Image Processing VIII, (4 December 2000); doi: 10.1117/12.408651
Show Author Affiliations
Ralf Mekle, Columbia Univ. (United States)
Andrew F. Laine, Columbia Univ. and Columbia-Presbyterian Medical Ctr. (United States)
Gerard Mark Perera, Columbia-Presbyterian Medical Ctr. (United States)
Robert DeLaPaz, Columbia-Presbyterian Medical Ctr. (United States)

Published in SPIE Proceedings Vol. 4119:
Wavelet Applications in Signal and Image Processing VIII
Akram Aldroubi; Andrew F. Laine; Michael A. Unser, Editor(s)

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