Abstract
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Objectives For β-amyloid brain PET with florbetaben, in addition to visual scan interpretation quantification via standardized uptake value ratios (SUVRs) and total brain volume affected may be of significant value. In a recent pilot trial, we identified the Hermes BRASS module as a potential tool to operator-independently determine both of these quantitative parameters. In this present work we evaluated the diagnostic performance of this tool when analyzing multi-center data.
Methods BRASS database generation: Florbetaben PET scans from 93 cognitively normal, β-amyloid-negative healthy volunteers (HVs). Database testing: 145 florbetaben PET scans (77 patients with probable AD, 68 HVs) obtained from a multi-center Phase 2 trial, individual voxelwise and VOI-based comparison with normal database, composite SUVRs obtained by BRASS compared to those obtained by reference technique (grey matter segmentation on individual MRIs, VOIs from modified AAL template).
Results The BRASS analysis of the florbetaben datasets was possible without operator-interventions within 41±4 sec. The composite SUVRs in ADs as determined by BRASS correlated significantly with those determined by the reference method (r=0.80, p<0.001). Composite SUVR discrimination between ADs and HVs: p<0.001, Cohen’s d = 1.37 for both approaches. In the ADs and HVs, 3.2±2.7 vs. 0.1±0.4 (p<0.001, Cohen’s d = 1.61) neocortical regions were defined by BRASS as pathologic (z-score > 2.5). The total brain volume affected by β-amyloid was 18.6±25.7 vs. 0.8±3.7ml for the ADs and HVs (p<0.001).
Conclusions Florbetaben BRASS demonstrated excellent ability in discriminating between ADs and HVs, both on a regional and a voxel-based level. Thus, this software has great potential in supporting the visual interpretation of florbetaben PET image data in a rapid, user friendly and operator-independent manner.
Research Support Bayer Healthcare, Berlin (Germany