Luca Sacchi (Italy)
University of Milan NeurologyAuthor Of 1 Presentation
UNRAVELLING THE ASSOCIATION BETWEEN AMYLOID-PET AND CSF BIOMARKERS: WHO REALLY DESERVES AN A+?
- Luca Sacchi (Italy)
Abstract
Background and Aims:
Correlation between CSF-Aβ42 and amyloid-PET is inconstant across the AD spectrum. However, they are considered interchangeable, along with Aβ42/40 ratio, for defining ‘Alzheimer’s Disease pathologic change’ (A+). We aimed at further unravelling the association between amyloid-PET and CSF biomarkers of AD in patients with low CSF-Aβ42.
Methods:
We included 23 patients who underwent 18F-Florbetaben-PET scan, MRI and CSF analysis showing reduced levels of Aβ42 within a 365 days interval. Thresholds used for dichotomization were: Aβ42<640 pg/mL (A+); pTau>61 pg/mL (T+); Aβ42/40<0.069 (ADratio). Amyloid-PET scans were visually classified as positive/negative and processed by four pipelines (SPMCL, SPMAAL, FSGM, FSWC). Transformation to Centiloid units was performed, setting threshold for PET-positivity to 20.1.
Results:
Different pipelines gave highly intercorrelated SUVRs (rho 0.93-0.99). The most significant findings were: pTau positive correlation with SPMCL and SPMAAL SUVRs (rho 0.56, p 0.0063; rho 0.51, p 0.0148 respectively) and Aβ42/40 negative correlation with SPMCL and SPMAAL SUVRs (rho -0.56, p 0.0058; rho -0.52, p 0.0117 respectively). In subregion analysis, SUVRs of precuneus, posterior cingulate and anterior cingulate cortices showed the highest correlation with pTau, while Aβ42/40 ratio best correlated with posterior cingulate SUVR. SUVRs were significantly higher in A+/T+ than in A+/T- (p 0.0018-0.0059) and in ADratio versus non ADratio subjects (p 0.0002). Combining either pTau or Aβ40 with Aβ42 significantly increased concordance with PET-status.
Conclusions:
Our data confirm that correlation between Aβ42 and PET SUVR does not hold after CSF-Aβ42 positivity has been reached and that PET measures show a stronger association with pTau and Aβ42/40 at this stage.
Presenter of 1 Presentation
UNRAVELLING THE ASSOCIATION BETWEEN AMYLOID-PET AND CSF BIOMARKERS: WHO REALLY DESERVES AN A+?
- Luca Sacchi (Italy)
Abstract
Background and Aims:
Correlation between CSF-Aβ42 and amyloid-PET is inconstant across the AD spectrum. However, they are considered interchangeable, along with Aβ42/40 ratio, for defining ‘Alzheimer’s Disease pathologic change’ (A+). We aimed at further unravelling the association between amyloid-PET and CSF biomarkers of AD in patients with low CSF-Aβ42.
Methods:
We included 23 patients who underwent 18F-Florbetaben-PET scan, MRI and CSF analysis showing reduced levels of Aβ42 within a 365 days interval. Thresholds used for dichotomization were: Aβ42<640 pg/mL (A+); pTau>61 pg/mL (T+); Aβ42/40<0.069 (ADratio). Amyloid-PET scans were visually classified as positive/negative and processed by four pipelines (SPMCL, SPMAAL, FSGM, FSWC). Transformation to Centiloid units was performed, setting threshold for PET-positivity to 20.1.
Results:
Different pipelines gave highly intercorrelated SUVRs (rho 0.93-0.99). The most significant findings were: pTau positive correlation with SPMCL and SPMAAL SUVRs (rho 0.56, p 0.0063; rho 0.51, p 0.0148 respectively) and Aβ42/40 negative correlation with SPMCL and SPMAAL SUVRs (rho -0.56, p 0.0058; rho -0.52, p 0.0117 respectively). In subregion analysis, SUVRs of precuneus, posterior cingulate and anterior cingulate cortices showed the highest correlation with pTau, while Aβ42/40 ratio best correlated with posterior cingulate SUVR. SUVRs were significantly higher in A+/T+ than in A+/T- (p 0.0018-0.0059) and in ADratio versus non ADratio subjects (p 0.0002). Combining either pTau or Aβ40 with Aβ42 significantly increased concordance with PET-status.
Conclusions:
Our data confirm that correlation between Aβ42 and PET SUVR does not hold after CSF-Aβ42 positivity has been reached and that PET measures show a stronger association with pTau and Aβ42/40 at this stage.