Amyloid PET, CSF Diagnose Early AD Equally with High Accuracy

September 30, 2015 - Amyloid PET diagnosis of early-stage Alzheimer disease (AD) is as effective as the previously used cerebrospinal fluid (CSF) sample method, according to a study conducted at Lund University in Sweden.

The study, the most extensive undertaken in the field so far, was designed to compare the diagnostic accuracy of CSF biomarkers and amyloid PET for diagnosing early-stage AD. The prospective, longitudinal BioFINDER study included 122 healthy elderly and 34 patients with mild cognitive impairment who developed AD dementia within 3 years (MCI-AD). β-Amyloid (Aβ) deposition in 9 brain regions was examined with [18F]-flutemetamol positron emission tomography (PET). CSF was analyzed with INNOTEST and EUROIMMUN ELISAs. The results were replicated in 146 controls and 64 patients with MCI-AD from the Alzheimer's Disease Neuroimaging Initiative study.

CSF measures for identifying MCI-AD were CSF Aβ42/t-tau and Aβ42/p-tau and performed better than CSF Aβ42 and Aβ42/40 (AUC difference 0.03–0.12, p < 0.05). Using nonoptimized cutoffs, CSF Aβ42/t-tau had the highest accuracy of all CSF/PET biomarkers (sensitivity 97%, specificity 83%).

Based on the results, the authors concluded that Amyloid PET and CSF biomarkers can identify early AD with high accuracy. There were no differences between the best CSF and PET measures and no improvement when combining them. Regional PET measures were not better than assessing the global Aβ deposition.

Image: Oskar Hansson and Sebastian Palmqvist (Photo: Björn Hansson).2

1. Palmqvist S, Henrik Zetterberg H, Niklas Mattsson N, Johansson P. Detailed comparison of amyloid PET and CSF biomarkers for identifying early Alzheimer disease. September 9, 2015, doi: http:/​/​dx.​doi.​org/​10.​1212/​WNL.​0000000000001991 Neurology 10.1212/WNL.0000000000001991.

2. Lund University. News and Press Releases.