The purpose of this service is to provide a robust and reliable index (called "Global Disease Index", GDI) in support of early clinical diagnosis of mild and prodromal Alzheimer's Disease (AD) patients. The procedures extracts and analyzes a small number of volumes from several areas of interest in MR images. These volumes are filtered to give intensity and textural features. A relatively small subset of these features is selected because it has been found to be strongly correlated with the conversion to Alzheimer's Disease and sufficient to give a reliable assessment. The user guide is available here.