Effect of Amyloid Imaging on the Diagnosis and Management of Patients with Cognitive Decline: Impact of Appropriate Use Criteria

Abstract

Background: Published appropriate use criteria (AUC) describe patients for whom amyloid positron emission tomography (PET) might be most useful. This study compared the impact of amyloid PET on diagnosis and management in subjects likely to either meet or not meet AUC.

Methods: Physicians provided a provisional diagnosis and management plan for patients presenting with cognitive decline before and after amyloid PET imaging with florbetapir F 18. Participants were classified as AUC-like or not, based on the prescan diagnosis and demographic features.

Results: In all, 125 of 229 participants (55%) were classified as AUC-like. Sixty-two percent of the AUC-like subjects had a change in diagnosis after scanning compared with 45% of the non-AUC subjects (p = 0.011). Both groups demonstrated high rates of change in their management plans after scanning (88.0% for AUC-like cases, 85.6% for non-AUC cases).

Conclusions: The impact of amyloid imaging on diagnosis and planned management was maintained and, if anything, amplified in AUC-like patients.

Fig. 1.

Impact of an Aβ1+ (a) and an Aβ- florbetapir PET scan (b) on proposed management plan changes in patients with incomplete workup at study entry (group B), shown as a function of AUC status (AUC-like or non-AUC). Values represent the percentages of patients in the respective population group with an increase (blue) or decrease (red; colors refer to the online version only) in intended use of a diagnostic test or treatment after PET scanning. Thus, for example, the top half of a shows that plans for additional neuropsychological testing were eliminated after PET scan results became known in more than 40% of group B (AUC-like patients with a positive scan), and plans for treatment with cholinesterase medication or memantine were added for more than 40% of the same patients. The bottom half of a shows directionally similar, but numerically smaller, trends in the non-AUC group. b By comparison with a positive PET scan, after a negative PET scan there were numerically smaller decreases in planned diagnostic testing and net decreases in planned use of cholinesterase medications. Npsych = Neuropsychological testing; Labs = any laboratory analysis of blood or urine samples performed to aid in dementia diagnosis including but not limited to tests for vitamin B₁₂ levels, thyroid function, or syphilis serology; FDG = FDG-PET; AopE = apolipoprotein E; AD Med = cholinesterase medication or memantine.