Elsevier

NeuroImage: Clinical

Volume 14, 2017, Pages 506-517
NeuroImage: Clinical

3D scattering transforms for disease classification in neuroimaging

https://doi.org/10.1016/j.nicl.2017.02.004Get rights and content
Under a Creative Commons license
open access

Highlights

  • We have developed and implemented a feature extraction method based on the three dimensional (3D) scattering transform.

  • We tested it for its ability to discriminate diseased from healthy subjects and subjects with mild cognitive impairment.

  • We have clearly shown that our proposed methodology achieves higher accuracy than the best competing methods.

  • The scattering transform linearizes diffeomorphisms leading to more separable disease states using a linear classifier.

  • Scattering representations are shown to be highly effective for the task of disease classification.

  • We present a visualization method to highlight areas that provide evidence for or against a certain class.

Abstract

Classifying neurodegenerative brain diseases in MRI aims at correctly assigning discrete labels to MRI scans. Such labels usually refer to a diagnostic decision a learner infers based on what it has learned from a training sample of MRI scans. Classification from MRI voxels separately typically does not provide independent evidence towards or against a class; the information relevant for classification is only present in the form of complicated multivariate patterns (or “features”). Deep learning solves this problem by learning a sequence of non-linear transformations that result in feature representations that are better suited to classification. Such learned features have been shown to drastically outperform hand-engineered features in computer vision and audio analysis domains. However, applying the deep learning approach to the task of MRI classification is extremely challenging, because it requires a very large amount of data which is currently not available. We propose to instead use a three dimensional scattering transform, which resembles a deep convolutional neural network but has no learnable parameters. Furthermore, the scattering transform linearizes diffeomorphisms (due to e.g. residual anatomical variability in MRI scans), making the different disease states more easily separable using a linear classifier. In experiments on brain morphometry in Alzheimer's disease, and on white matter microstructural damage in HIV, scattering representations are shown to be highly effective for the task of disease classification. For instance, in semi-supervised learning of progressive versus stable MCI, we reach an accuracy of 82.7%. We also present a visualization method to highlight areas that provide evidence for or against a certain class, both on an individual and group level.

Keywords

Scattering representation
Feature extraction
MRI classification

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