This paper presents a new methodology to be used in measuring brain atrophy on imaging exams of patients with neurodegenerative diseases. The methods foresee the usage of a mean brain that serves as a reference volume. Color maps were created following a cold-hot color scheme where highlighted regions of atrophy based on the standard deviation and mean values voxel-wise of the mean brain. Direct measures of the atrophy grade were obtained by statistical comparisons between the mean brain volume and regions identified as atrophied. The proposed method was evaluated using 35 patients, 16 had been previously diagnosed as Alzheimer cases, 7 as MCI, 2 as Vascular Dementia and 10 as Complainers. The mean brain used in this study was created using affine transformations to drive the necessary volume registration and were composed of healthy patients. All diagnostics followed a neuropsychological protocol.