Moreover, they correlate better with the condition of the subject rather than with age. In general, the AD brains presented greater anisotropy in their gray matter texture than the control brains. Both 2D features and 3D features correlate with the MMSE score, indicating that the information is

already available in each individual layer.13 Human applications in schizophrenia Texture analysis can also provide feature parameters for different classes, which can then be used for classification. Generalized 4D co-occurrence matrices have been used to analyze the 3D MRI T2-weighted brain images from controls and patients with schizophrenia. Inhibitors,research,lifescience,medical The ROI approach has a number of potential problems: inter- and intraoperator reproducibility; difficulties detecting neuroanatomic boundaries; and the requirements that are of interest have to be specified from the outset. This approach does not need prior hypotheses and, because it is automated, reproducibility and comparability Inhibitors,research,lifescience,medical are ensured. Methods Two groups of subjects were investigated and analyzed in this study: 19 control subjects and 21 patients with schizophrenia. The controls were matched for age, gender, and social class.

3D MRI T2-wcightcd images were Inhibitors,research,lifescience,medical collected for each subject. Each data set consisted of slices with a 0.856-mm spatial resolution with interslice distance of 3 mm. The images were segmented such that only the brain component was extracted for further analysis. The anisotropic sampling of the data along the z axis (interslice direction) is handled by an appropriate scaling factor of 3.5 (3/0.856) for all data sets.

For the texture analysis, we use generalized co-occurrence matrices.14 3D texture analysis The co-occurrence matrix Inhibitors,research,lifescience,medical is a generalized histogram, which records the frequency with which a certain combination of characteristics appear in the relevant position. Usually the main characteristic used is the gray value of the image, but other features can be used, such as gradient magnitude or relative orientation of the gradient vectors. Because they are independent of rotation Inhibitors,research,lifescience,medical and translation of the data, co-occurrence matrices offer descriptors that Calpain Proteasome purification include these properties. The calculated co-occurrence matrix was w[g(i), g(j), a(i,j), d(i,;j)]], where w is the frequency of the occurrence of a voxel pair i,j, with gradient, magnitude g(i) and g(j) respectively, an angle a (i,j) between their gradient vectors, and a distance d(i,j) from each other. Results Three series of experiments were conducted: one considering the whole brain, one considering the bottom half of the brain, and one considering the bottom quarter of the brain. The division of the brain was performed by identifying the slices that are anatomically most similar to slices 12 and 24 of the anatomical atlas of Talairach and Toumoux.15 In each experiment, each element of the co-occurrence matrix was tested as a class discriminator according to the t test.