CT measurement of suprasellar cistern predicts rate of cognitive decline in Alzheimer's disease
Previous studies reveal significant relationships between some quantitative computed tomography (CT) measures and level of cognitive functioning in patients with Alzheimer's disease (AD). This study was designed to determine whether measurements from CT scans of AD patients could predict future rates of decline in cognitive function. Subjects were 8 men and 19 women diagnosed with probable AD. CT measures included bifrontal ratio, bicaudate ratio, and areas of lateral ventricles, third ventricle, and suprasellar cistern (SSC). Measures of cognitive and adaptive functioning were obtained at the time of the scan and on follow-up. Of the CT measures, the SSCR (SSC corrected for intracranial area) was the most highly correlated with Mini-Mental State Exam (MMSE) score and other cognitive measures at the time of the scan. Follow-up data were obtained for those 20 individuals who were mildly to moderately demented at the time of the scan (MMSE > or = 10). Rate of change was calculated for each neuropsychological measure. The SSCR correlated significantly with rate of change for MMSE and other measures of cognitive and adaptive functioning. This study demonstrates that CT measurement of the SSC can predict the subsequent rate of neurocognitive decline in AD patients.