VISUALIZATION AND QUANTIFICATION OF RATES OF ATROPHY IN ALZHEIMERS-DISEASE

Background Definitive diagnosis of Alzheimer's disease requires histol ogical examination of brain tissue. In life, brain atrophy can be visu alised by computed tomography or magnetic resonance (MR) imaging, but the atrophy due to the disease is difficult to distinguish from that c aused by normal ageing. We have investigated use of accurate positiona l matching (registration) and digital subtraction of serially acquired MR brain scans to allow determination of rates of global and regional atrophy. Methods This technique was applied to eleven patients with c linically diagnosed Alzheimer's disease and eleven age-matched control s. Each individual had two scans approximately 1 year apart; scan inte rvals were matched between the groups. Findings The median rate atroph y was significantly greater in the Alzheimer's disease group than in t he control group (12 . 3 [range 5 . 8 to 23 . 6] vs 0 . 3 (-1 . 2 to 1 . 7) mL per year; p<0 . 0001). There was no overlap between the group s. Furthermore, three non-demented individuals at risk of familiar Alz heimer's disease had scans 6-14 months apart and showed greater rates of volume loss than the controls; these three individuals have subsequ ently developed symptoms. Interpretation This technique may be useful for the diagnosis of Alzheimer's disease, the assessment of disease pr ogression, and the evaluation of potential treatments.