The Imaging Dementia-Evidence for Amyloid Scanning (IDEAS) Study will establish an open-label, longitudinal cohort study to assess the impact of amyloid PET on patient outcomes. The study will be performed in accordance with the Center for Medicare & Medicaid Services (CMS) policy of Coverage with Evidence Development (CED) in Medicare beneficiaries who meet the Appropriate Use Criteria (AUC) for amyloid PET (Johnson et al. 2013). Our hypothesis is that amyloid PET will decrease uncertainty and increase confidence in the underlying cause of cognitive impairment, that this will translate into earlier counseling and interventions in these domains, and that these interventions will lead to improved outcomes.

The IDEAS Study is an observational, open-label, longitudinal cohort study designed to assess the impact of amyloid PET on patient-oriented outcomes in Medicare beneficiaries with mild cognitive impairment (MCI) or dementia of uncertain etiology. The study falls under the Centers for Medicare & Medicaid Services (CMS) Coverage with Evidence Development (CED) policy. A total of 18,488 Medicare beneficiaries meeting Appropriate Use Criteria (AUC) for amyloid PET will be enrolled over 24 months at sites throughout the United States. Dementia specialists will team with PET facilities able to perform amyloid PET and with trained radiologists/nuclear medicine physicians, all of whom will consent to completing the data requirements and timelines for the study. Amyloid PET will be performed and interpreted at each facility with results provided to the ordering physician for support in further clinical decision making, which will be captured for the study.

Our over-arching hypothesis is that, in diagnostically uncertain cases, knowledge of amyloid status as determined by amyloid PET will lead to significant changes in patient management, and that this will translate into improved long-term outcomes. We will pursue two specific aims:

Aim 1 investigates the impact of amyloid PET on short-term patient management, by comparing pre-PET intended management (ascertained in a case report form [CRF] prior to PET) to post-PET actual management 90-days post-PET). The primary objective will be to test whether amyloid PET leads to a ≥ 30% change between intended and actual patient management within 90 days in a cumulative endpoint consisting of: Alzheimer's disease (AD) drug therapy, other drug therapy, and counseling about safety and future planning. Secondary objectives will assess the impact of amyloid PET results on clinical diagnosis and prevention of unnecessary diagnostic procedures and treatments.

Aim 2 utilizes Medicare claims data to compare medical outcomes at 12 months for patients enrolled in the longitudinal cohort (amyloid PET-known) with those for a matched control cohort of patients who have never undergone amyloid PET imaging (amyloid PET-naïve). The primary objective will be to determine if amyloid PET in the amyloid PET-known cohort of patients is associated with a ≥ 10% reduction in hospitalizations and emergency room visits in comparison to the matched amyloid PET-naïve patients. Secondary objectives will examine whether knowledge of amyloid PET status reduces hospitalizations related to ambulatory-sensitive conditions, whether the association between amyloid PET knowledge and health outcomes varies by baseline cognitive status (MCI versus dementia) and amyloid status (amyloid positive versus negative). The amyloid PET-naïve cohort will be identified via a matching algorithm where each individual in the amyloid PET-known cohort will be matched to one individual with similar dementia diagnosis, pre-scan dementia-related resource utilization, age, race, gender, ethnicity, geographic location, and comorbid chronic conditions likely to impact cognition or the outcomes of interest seen at the same time as the amyloid PET-known patient (concurrent control).

In pursuing these Aims, we will generate valuable observational data on clinical utility that will inform future use of this technology in diagnostic algorithms, and develop a cohort of patients who undergo amyloid PET and can serve as a foundation to address future research questions.

Inclusion Criteria:

• 65 and older;
• Medicare beneficiary;
• Diagnosis of MCI or dementia, according to DSM-IV and/or National Institutes of Aging-Alzheimer's Association criteria, verified by a dementia specialist within 24 months (American Psychiatric Association. 2000; McKhann et al. 2011; Albert et al. 2011);
• Meets AUC:
• Cognitive complaint verified by objectively confirmed cognitive impairment;
• The etiologic cause of cognitive impairment is uncertain after a comprehensive evaluation by a dementia specialist, including general medical and neurological examination, mental status testing including standard measures of cognitive impairment, laboratory testing, and structural neuroimaging as below;
• Alzheimer's disease is a diagnostic consideration;
• Knowledge of amyloid PET status is expected to alter diagnosis and management.
• Head MRI and/or CT within 24 months prior to enrollment;
• Clinical laboratory assessment (complete blood count [CBC], standard blood chemistry profile, thyroid stimulating hormone [TSH], vitamin B12) within the 12 months prior to enrollment;
• Able to tolerate amyloid PET required by protocol, to be performed at a participating PET facility;
• English or Spanish speaking (for the purposes of informed consent);
• Willing and able to provide consent. Consent may be by proxy.

Exclusion Criteria:

• Normal cognition or subjective complaints that are not verified by cognitive testing.
• Knowledge of amyloid status, in the opinion of the referring dementia expert, may cause significant psychological harm or otherwise negatively impact the patient or family.
• Scan is being ordered solely based on a family history of dementia, presence of apolipoprotein E, or in lieu of genotyping for suspected autosomal mutation carriers.
• Scan being ordered for nonmedical purposes (e.g., legal, insurance coverage, or employment screening).
• Cancer requiring active therapy (excluding non-melanoma skin cancer);
• Hip/pelvic fracture within the 12 months prior to enrollment;
• Body weight exceeds PET scanner weight limit;
• Life expectancy less than 24 months based on medical co-morbidities;
• Residence in a skilled nursing facility.

Participants must be Medicare beneficiaries referred by qualified dementia specialists and must meet AUC for amyloid PET (Johnson et al. 2013).