Tissue segmentation of the brain in Alzheimer disease

To compare brain tissue in patients with Alzheimer disease with that in elderly control subjects by using high-resolution MR imaging and quantitative tissue-segmentation techniques.

MR imaging of the brain was performed in 21 patients with Alzheimer disease and 17 control subjects. A computerized segmentation program was used to quantify volumes of ventricular and sulcal cerebrospinal fluid (CSF), white matter, cortical gray matter, and white matter signal hyperintensity. Statistical analysis was performed using analysis of variance.

We found a significant decrease in total brain tissue and cortical gray matter and an increase in the ventricular and sulcal CSF in Alzheimer patients compared with control subjects. There was no difference in the volume of white matter. More white matter signal hyperintensities were found in Alzheimer patients, and a significant interaction between age and group was noted. Neuropsychological test scores correlated significantly with sulcal CSF in patients with Alzheimer disease.

Semiautomated segmentation of MR images of the brains of patients with Alzheimer disease reveals significant brain atrophy attributable to loss of cortical gray matter, which is compatible with the pathologic features of Alzheimer disease. There is also a significant increase in white matter signal hyperintensities. Tissue segmentation may increase our understanding of dementia but, as yet, when used alone, it does not play a role in the premorbid diagnosis of Alzheimer disease.