Magnetic resonance measures in Alzheimer disease: Their utility in early diagnosis and evaluating disease progression

We sought to identify the most reliable magnetic resonance (MR) measures fo r the diagnosis and staging of Alzheimer disease (AD) in a clinical setting and to estimate, for different degrees of dementia, the rate of change of cerebral atrophy in certain regions of interest (ROIs). Forty-two probable AD patients and eight normal controls underwent MR brain scans, neurologica l examinations, and neuropsychological testing. We computed each subject's corpus callosum width, ventricular size, right and left temporal lobe areas , interuncal distance, and assessed the degree of cortical atrophy. We also estimated the rate of change for Information-Memory-Concentration Test sco res and for temporal lobe areas and corpus callosum width. Measures of temp oral lobe area and subjective evaluation of temporal lobe atrophy both serv ed to distinguish controls from mild AD cases (p < 0.05), whereas only the latter differentiated moderate from severe patients (p < 0.05). The rate of change for temporal lobe areas remained constant over different AD stages, whereas those for corpus callosum width and for cognitive impairment were greater for severe cases (p < 0.05). Our findings imply that measurements o f temporal lobe area and ratings of temporoparietal atrophy can be useful i n the diagnosis and staging of AD and suggest that atrophy progressed at di fferent rates in selected ROIs for various stages of AD severity.