{"entity":{"id":"ideas-amyloid","kind":"trial","name":"IDEAS (Imaging Dementia-Evidence for Amyloid Scanning)","aka":["IDEAS study"],"tldr":"A large US Medicare study asked whether a brain scan that detects amyloid protein (a hallmark of Alzheimer's disease) actually changes what doctors do for patients with memory problems; it found that doctors changed the treatment or diagnosis plan for roughly six in ten patients after seeing the scan.","summary":"IDEAS was a single-group, multisite, longitudinal observational study run by the American College of Radiology under Medicare's Coverage with Evidence Development programme, designed to determine whether amyloid PET changes clinical management in Medicare beneficiaries with mild cognitive impairment (MCI) or dementia of uncertain aetiology who met published appropriate-use criteria. Dementia specialists recorded an intended management plan before amyloid PET and again 90 days after, covering Alzheimer's disease drug therapy, other drug therapy, and safety/future-planning counselling; the study was powered to detect a 30% or greater change in each of the MCI and dementia groups.\n\nOf 18,488 registered participants, 11,409 were included in the primary analysis (6,905 with MCI, 4,504 with dementia). The composite management endpoint changed in 60.2% of the MCI group and 63.5% of the dementia group, both far exceeding the 30% target; Alzheimer's disease drug use changed most often. The aetiological diagnosis flipped from Alzheimer's to non-Alzheimer's disease in 25.1% of patients and the reverse in 10.5%. A later health-utilisation analysis found a smaller-than-hoped 4.5% relative reduction in 12-month hospitalisations, short of the pre-specified 10% effect size, though patients with positive scans were hospitalised less often than those with negative scans.\n\nIDEAS is a management-impact study, not a trial of clinical outcomes from a therapeutic intervention, and it predates the era of anti-amyloid disease-modifying drugs (lecanemab, donanemab), which have since made amyloid status a treatment-eligibility gate rather than only a diagnostic aid. Its results, together with the follow-on New IDEAS study (NCT04426539), underpinned the 2023 removal of the Medicare national coverage determination that had required amyloid PET to be performed only within an approved research study.","status":"completed","asOf":"2026-09-22","links":[{"label":"JAMA 2019: IDEAS primary results (Rabinovici et al.)","url":"https://jamanetwork.com/journals/jama/fullarticle/2729371"},{"label":"ClinicalTrials.gov: NCT02420756","url":"https://clinicaltrials.gov/study/NCT02420756"},{"label":"CMS: amyloid PET national coverage determination removal decision memo","url":"https://www.cms.gov/medicare-coverage-database/view/ncacal-decision-memo.aspx?proposed=N&ncaid=308"}],"tags":["diagnostic trial","neurology","amyloid PET","coverage with evidence development"],"related":["medicare-ced"],"indications":[],"sections":[],"technologies":[],"targets":[],"drugs":[],"companies":[],"institutions":[],"pathways":[],"terms":[],"trials":[],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"nct":"NCT02420756","phase":"observational","setting":"Medicare beneficiaries with mild cognitive impairment or dementia of uncertain cause, evaluated by dementia specialists; a coverage-with-evidence-development registry study, not a treatment trial","sponsor":"American College of Radiology","result":"Amyloid PET changed the composite management plan (drug therapy or counselling) within 90 days in 60.2% of patients with mild cognitive impairment and 63.5% of patients with dementia of uncertain cause, both far exceeding the pre-specified 30% threshold, among 11,409 analysed patients (Rabinovici et al., JAMA 2019)","yearReported":2019,"enrolled":18488,"enrolledBasis":"registered","enrolledNote":"Registry enrolment (18,488) is the total registered; the JAMA 2019 primary management-change analysis was on 11,409 patients with complete pre- and post-scan data.","outcomes":[{"endpoint":"Change in composite patient management plan within 90 days, mild cognitive impairment group","primary":true,"unit":"%","arms":[{"name":"Pre-PET vs post-PET documented plan (MCI)","n":6905,"value":60.2,"note":"95% CI 59.1-61.4%, exceeding the pre-specified 30% threshold, p<0.001"}],"source":"https://jamanetwork.com/journals/jama/fullarticle/2729371"},{"endpoint":"Change in composite patient management plan within 90 days, dementia of uncertain cause group","primary":true,"unit":"%","arms":[{"name":"Pre-PET vs post-PET documented plan (dementia)","n":4504,"value":63.5,"note":"95% CI 62.1-64.9%, exceeding the pre-specified 30% threshold, p<0.001"}],"source":"https://jamanetwork.com/journals/jama/fullarticle/2729371"},{"endpoint":"Change in aetiological diagnosis","unit":"%","arms":[{"name":"Amyloid PET, all patients","n":11409,"value":25.1,"note":"changed from Alzheimer's disease to non-Alzheimer's; 10.5% changed the other way"}]}]},"route":"/trials/ideas-amyloid/","neighbours":{"term":[{"id":"medicare-ced","kind":"term","name":"Medicare coverage with evidence development","route":"/terms/medicare-ced/"}]}}