Diagnostic performance of the cingulate island sign ratio for differentiating dementia with Lewy bodies from Alzheimer's disease changes depending on the mini-mental state examination score

The cingulate island sign (CIS) ratio is a diagnostic adjunct for differentiating dementia with Lewy bodies (DLB) from Alzheimer's disease (AD). A recent study showed that the CIS ratio in DLB changed depending on the Mini-Mental State Examination (MMSE) score. We aimed to evaluate whether the diagnostic performance (sensitivity and specificity) of the CIS ratio for differentiating DLB from AD changes depending on the MMSE score.