Amyloid positron emission tomography (PET) changes etiologic diagnosis for patients with and without dementia, increasing diagnostic confidence and changing treatments received, according to a study published in JAMA Neurology.

Adno de Wilde, MD, of the Department of Neurology & Alzheimer Center, Amsterdam Neuroscience at the VU University Medical Center, and associates conducted a prospective cohort study to understand the correlations between the effects of amyloid PET and clinical diagnosis, confidence in diagnosis, treatment, and patients’ experience.

The investigators invited 866 patients to receive amyloid PET using fluoride-18 florbetaben; 476 of these patients participated (55%) in the study and an additional 31 patients with mild cognitive impairment (MCI) were asked to participate.

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The primary outcomes were any diagnosis changes made post-PET, diagnostic confidence, and treatment.

A preamyloid and postamyloid PET diagnosis was determined by neurologists for each participant for a clinical syndrome (dementia, MCI, and subjective cognitive decline [SCD]) and a suspected etiology including Alzheimer disease (AD) or non-AD: confidence levels varied from 0 to 100%. Neurologists also investigated patient treatments, medication, and care.

Of the 507 participants (average age, 65 years; 201 women) 164 had AD dementia (32%), 70 had non-AD dementia (14%), 114 had MCI (23%), and 159 had SCD; 242 patients had positive amyloid PET results (48%).

A quarter of the patients had changes in suspected etiologies postamyloid PET: negative PET results influenced these changes more than positive PET results (31% vs 18%, respectively). In addition, most post-PET changes in suspected etiology took place in older patients (>65 years).

The researchers noted an increase in average diagnostic confidence: 80 to 89. Altered patient treatments post-PET were reported in 123 individuals due to additional analysis and therapies (24%).

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“This prospective diagnostic study provides a bridge between validating amyloid PET in a research setting and implementing this diagnostic tool in daily clinical practice,” the authors concluded. “Both amyloid-positive and amyloid-negative results have substantial associations with changes in diagnosis and treatment, both in patients with and without dementia.”


de Wilde A, van der Flier WM, Pelkmans W, et al. Association of amyloid positron emission tomography with changes in diagnosis and patient treatment in an unselected memory clinic cohort: the ABIDE Project. JAMA Neurol. [Published online]. June 11, 2018. doi:10.1001/jamaneurol.2018.1346