Frontotemporal dementia and Alzheimer disease: evaluation of cortical atrophy with automated hemispheric surface display generated with MR images

PURPOSE: To determine the features of cortical atrophy in frontotemporal dementia (FTD) and Alzheimer disease by using a hemispheric surface display generated with magnetic resonance (MR) images. MATERIALS AND METHODS: The extent of cortical atrophy was evaluated with automated MR hemispheric surface display and volumetry in 18 patients with FTD and in 18 matched patients with Alzheimer disease. Results were compared with those in 18 healthy, matched control subjects. RESULTS: Most cortical regions were significantly atrophic in FTD and Alzheimer disease. The frontal and anterior temporal lobes were significantly more atrophic in FTD than in Alzheimer disease. The mean hemispheric-to-intracranial volume ratio in patients with FTD (56.2%) and those with Alzheimer disease (58.4%) was significantly smaller than the ratio in the control subjects (66.0%). Asymmetry of hemispheric volume was significantly larger in the FTD group than in the Alzheimer disease and control groups. CONCLUSION: Cortical atrophy in FTD is more widespread than was previously thought. Asymmetric frontal and anterior temporal atrophy is a distinctive feature of FTD and distinguishes it from Alzheimer disease. Hemispheric surface display is a useful complement to tomographic images and is useful for the evaluation of focal cortical atrophy in degenerative dementias, especially FTD.