Wavelet Features for Recognition of First Episode of Schizophrenia from MRI Brain Images

Machine learning methods are increasingly used in various fields of medicine, contributing to early diagnosis and better quality of care. These outputs are particularly desirable in case of neuropsychiatric disorders, such as schizophrenia, due to the inherent potential for creating a new gold standard in the diagnosis and differentiation of particular disorders. This paper presents a scheme for automated classification from magnetic resonance images based on multiresolution representation in the wavelet domain. Implementation of the proposed algorithm, utilizing support vector machines classifier, is introduced and tested on a dataset containing 104 patients with first episode schizophrenia and healthy volunteers. Optimal parameters of different phases of the algorithm are sought and the quality of classification is estimated by robust cross validation techniques. Values of accuracy, sensitivity and specificity over 71% are achieved

On classifying disease-induced patterns in the brain using diffusion tensor images

Abstract. Diffusion tensor imaging (DTI) provides rich information about brain tissue structure especially in the white matter, which is known to be affected in several diseases like schizophrenia. Identifying patterns of brain changes induced by pathology is therefore crucial to clinical studies. However, the high dimensionality and complex structure of DTI make it difficult to apply conventional linear statistical and pattern classification methods to identify such patterns. In this paper, we present a novel framework that uses a combination of DTI-based anisotropy and geometry features to effectively identify brain regions with pathology-induced abnormality, and to classify brains into the diseased and healthy groups. Our method first directly estimates the underlying overlap between the patient and control groups, based on a semi-parametric Bayes error estimation method. By ranking voxels based on these estimation results, the method identifies abnormal brain regions from which features are extracted through Kernel Principal Component Analysis (KPCA) for subsequent classification. Application of the method to a dataset of controls and patients with schizophrenia, demonstrates promising accuracy of this framework in identifying brain patterns to separate two groups, and hence aiding in prognosis and treatment