Recently, delayed clearance of the CSF tracer in the entorhinal cortex was observed in cognitively impaired patients with idiopathic normal pressure hydrocephalus [314,315], a potentially treatable form of cognitive impairment, in late life [316], which may exhibit AD-like pathological features, including the deposition of amyloid-β and tau [317]. This evidence concerns the gene MAPT and Alzheimer disease.