Width of the third ventricle assessed by transcranial sonography can monitor brain atrophy in a time- and cost-effective manner--results from a longitudinal study on 500 subjects.

Ventricular width and its enlargement over time are discussed as promising markers for preclinical brain atrophy. The aim of our study was to define whether brain atrophy can reliably be monitored by transcranial ultrasound (TCS). In a prospective longitudinal trial over 5years, 500 healthy persons were examined by a standardized protocol with TCS in addition to an extensive cognitive testing using the Consortium to Establish a Registry of Alzheimer's Disease - Neuropsychological Testing (CERAD-NP). TCS displayed the third ventricle in 96% of all cases at the follow-up with a high intra-individual reproducibility and excellent inter-rater coefficient (0.992). The mean diameter of the third ventricle in subjects with a cognitive decline was significantly wider (6mm±2) than in subjects with normal cognitive testing results (4.6mm±1.8). We demonstrated that the width of the third ventricle, as a marker of brain atrophy can reliably be monitored by using TCS as a non-invasive, time- and cost-effective method. We provide evidence that the assessed width of the third ventricle can differentiate between subjects with a normal cognitive performance and subjects with a cognitive decline. TCS may be a useful screening tool in the early diagnosis of cognitive decline.