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Aβ plaques in the brain: Either you have them, or you don’t. At least that is what widely used, up-down PET tracer thresholds would have you believe. Not so. Researchers have developed a staging model of Aβ deposition based on the regional progression of Aβ pathology through the brain. Constructed and validated with data from more than 600 volunteers, the four-stage scheme correlated with clinical disease stage, and detected Aβ in many cognitively normal people who would have been considered Aβ-negative by binary, global measures alone.
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