asl perfusion mri predicts cognitive decline and conversion from mci to dementia we compared the predictive value of cerebral perfusion as measured by arterialspin labeling magnetic resonance imaging aslmri with mriderived hippocampal volume for determining future cognitive and functional decline and subsequent conversion from mild cognitive impairment to dementia fortyeight mild cognitive impairment subjects received structural and aslmri scans at baseline and clinical and neuropsychologic assessments annually thirteen subjects became demented during the period of longitudinal observation 2710 y cox regression analyses suggest that baseline hippocampal volume relative risk rr099 p0004 baseline right inferior parietal rr064 p001 and right middle frontal rr073 p001 perfusion were associated with conversion to dementia results from linear mixed effects modeling suggest that baseline perfusion from the right precuneus predicted subsequent declines in clinical dementia rating sum of boxes p0002 functional activates questionnaire p001 and selective attention ie stroop switching p0009 whereas baseline perfusion from the right middle frontal cortex predicted subsequent episodic memory decline ie total recognition discriminability score from the california verbal learning test p003 these results suggest that hypoperfusion as detected by aslmri can predict subsequent clinical functional and cognitive decline and may be useful for identifying candidates for future alzheimer disease treatment trials