Tissue segmentation of the brain in Alzheimer disease.

TLDR

Tissue segmentation may enhance understanding of dementia but is not yet useful for premorbid Alzheimer diagnosis. The study compared brain tissue volumes in Alzheimer patients and elderly controls using high‑resolution MR imaging and quantitative segmentation. MR imaging of 21 Alzheimer patients and 17 controls was followed by computerized segmentation of CSF, white matter, cortical gray matter, and white matter hyperintensities, with statistical analysis via ANOVA. Semiautomated MR segmentation shows Alzheimer patients have reduced total brain and cortical gray matter, enlarged ventricular and sulcal CSF, and more white matter hyperintensities, with these changes correlating with neuropsychological scores and reflecting typical Alzheimer pathology.

Abstract

PURPOSE 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. METHODS 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. RESULTS 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. CONCLUSION 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.