Comparing VBM and ROI analyses for detection of gray matter abnormalities in Patients with Bipolar Disorder

Background and Aim : With the increasing efforts to the better understanding of psychiatric diseases, detection of brain morphological alterations are necessary. The aim of this study is comparing two methods-voxel based morphometry (VBM) and region of interest (ROI) analyses- to identify significant gray matter changes of patients with bipolar I disorder (BP I).Methods : The structural MRI were obtained in a total of 50 subjects (25 healthy subjects with a mean age of 34.488.32 years as a control group and 25 patients with a mean age of 37.6810.88 years). We compared the gray matter alteration results obtained by VBM analysis using DARTEL approach with those obtained using ROI analysis which applies three probabilistic brain atlases namely, hammers, lpba40, and neuromorphometrics atlases. All analyses were conducted via the Computational Anatomy Toolbox (CAT12) implemented in Statistical Parametric Mapping (SPM12) software package.Results : The VBM findings suggested that gray matter reductions in left precentral and right precuneus of the patients compared to healthy subjects. However, several areas reached the level of significance in ROI analysis. Most regions detected have deficits in gray matter volumes in the patients compared to the control group except bilateral pallidum.Conclusion : Although the two methods exhibit different kinds of information, they complement each other. Therefore, the selection of a method should be guided by the purpose of research.

Keywords:

voxel-based morphometry , region of interest analysis , bipolar disorder , MRI , brain