White matter lesions and T1 changes were identified using NMR and then compared between groups of patients suffering from dementia of the Alzheimer type (DAT), Multiple infarct dementia (MID) and normal controls. All DAT and MID patients were also imaged with a gamma camera using 123Iodo-n-isopropyl-amphetamine, a radiopharmaceutical whose uptake in the brain follows the regional blood flow. While NMR was not able to differentiate between DAT and MID, 19 out of 21 DAT patients compared to four out of 18 MID patients showed bilateral parietal lesions on IMP scans.