We have just published an article in the journal Brain on the relationship between brain  amyloid-β accumulation, cerebral blood flow and tissue loss. The abstract is available here.

Amyloid-β accumulation is a key feature of Alzheimer's disease, and is known to be related to brain tissue loss, but it is less clear how it is related to functional brain changes, including altered cerebral blood flow. Our paper is called "Association of brain amyloid-β with cerebral perfusion and structure in Alzheimer's disease and mild cognitive impairment". We used PET imaging of brain amyloid-β, combined with MRI measurements of cerebral blood flow and structural volume, in a cohort including both cognitively healthy controls and patients with different degrees of cognitive impairment.

We found that increased brain amyloid-β accumulation is associated with reduced cerebral blood flow, both in cognitively healthy controls, and patients with mild cognitive impairment or Alzheimer's disease with dementia. We also found some indications that high amyloid-β may be associated with greater cerebral blood flow reduction in controls and greater volume reduction in symptomatic disease stages, which is in line with the widely held assumption that amyloid-β accumulation leads to functional brain changes before it leads to structural changes. Naturally, longitudinal studies are needed to verify this.