Clinical Correlates of Alzheimer's Disease With and Without Silent Radiographic Abnormalities

To determine whether patients with Alzheimer's disease (AD) who do not have historical or clinical evidence of stroke but who do have computed tomographic or magnetic resonance imaging evidence of noncortical lesions smaller than 2 cm or periventricular “caps” differ from other patients with AD. The computed tomographic or magnetic resonance imaging scans of 158 patients meeting criteria of the National Institute of Neurological Disorders and Stroke—Alzheimer's Disease and Related Disorders Association for probable AD were reviewed by one neuroradiologist. Two measures of disease severity—the Modified Mini-Mental State examination and the Blessed Dementia Rating Scale (Part I)—were subjected to two-way analysis of variance with scan type (computed tomography or magnetic resonance imaging) and lesion number as between-group factors and age and disease duration as covariates. No relationship was seen between lesion number or periventricular caps and disease severity. In this cross-sectional analysis using these clinical measures, patients with AD who have well-defined radiographic abnormalities cannot be differentiated from patients with AD who do not have them.