Publications

This material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author's copyright. In most cases, these works may not be reposted without the explicit permission of the copyright holder.

Search for Publication


Year(s) from:  to 
Author:
Keywords (separated by spaces):

Detecting and Infering Brain Activation from functional MRI by Hypothesis-Testing based on the Likelihood Ratio

D. Ekatodramis, G. Székely and G. Gerig
182, 1998
Swiss Federal Institute of Technology ETH, Computer Vision Laboratory

Abstract

For the measure of brain activation in functional MRI many methods compute a heuristically chosen metric. The statistic of the underlying metric which is implicitely derived from the original assumption about the noise in the data, provides only an indirect way to the statistical inference of brain activation. We propose an alternative procedure by presenting a binary hypothesis-testing approach. This approach treats the problem of detecting brain activation at its origin by directly deriving a test statistic based on the probabilistic model of the noise in the data. Thereby, deterministic or parameterized models for the hemodynamic response can be considered. Results show that time series models can be detected even if they are characterized by unknown parameters, associated with the unclear nature of the mechanisms that mediate between neuronal stimulation and hemodynamic brain response. The likelihood ratio tests proposed in this paper are very efficient and robust in making a statistical inference about detected regions of brain activation. To validate the usefulness of our approach we present a simulation environment for functional MRI. This environment also serves as a testbed for comparative study and systematic tests.


Download in postscript format
@Techreport{eth_biwi_00137,
  author = {D. Ekatodramis and G. Székely and G. Gerig},
  title = {Detecting and Infering Brain Activation from functional MRI by Hypothesis-Testing based on the Likelihood Ratio},
  year = {1998},
  month = {March},
  number = {182},
  institution = {Swiss Federal Institute of Technology ETH, Computer Vision Laboratory},
  keywords = {medical image analysis, functional imaging, signal detection, hypothesis testing}
}