Amyloid burden quantification depends on PET and MR image processing methodology

Guilherme D Kolinger1, David Vállez García1, Antoon T M Willemsen1

  • 1Medical Imaging Center, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.

Plos One
|March 5, 2021
PubMed

Insights

Image processing methods significantly impact Alzheimer's Disease amyloid quantification. Intensity-based metrics are robust, while volumetric measures require careful processing in Native Space for reliable results.

Area of Science:

  • Neuroimaging
  • Biomarkers
  • Alzheimer's Disease Research

Background:

  • Positron emission tomography (PET) enables in-vivo quantification of amyloid load, crucial for Alzheimer's Disease (AD) assessment.
  • Image processing methodologies can introduce variability, potentially affecting the accuracy of amyloid quantification in AD.
  • Standardized and robust quantification methods are essential for reliable clinical assessment and research in AD.

Purpose of the Study:

  • To investigate the influence of different semi-automatic image processing pipelines on amyloid quantification in AD.
  • To compare the impact of various spatial normalization techniques and grey matter segmentation strategies on quantification metrics.
  • To identify processing pipelines that yield robust and reproducible amyloid load measurements for AD assessment.

Main Methods:

  • Analysis of PET images in Native Space and Standard Space using non-rigid spatial transformations.
  • Exploration of maximum a posteriori (MAP) approaches and tissue probability maps (TPM) for regularization.
  • Evaluation of grey matter segmentation performed before and after spatial normalization, and using a population-based template.
  • Assessment of five quantification metrics: two intensity-based, two volumetric-based, and one multi-parametric feature.

Main Results:

  • Intensity-based metrics showed minimal impact (≤10%) from spatial normalization and segmentation methods, comparable to test-retest variability.
  • Volumetric and multi-parametric features exhibited significant sensitivity to image processing, with variability up to 45%.
  • Analysis in Native Space without non-rigid transformations was recommended for volumetric measurements.

Conclusions:

  • Image processing methodology significantly influences amyloid quantification, particularly for volumetric and multi-parametric metrics.
  • Intensity-based metrics offer greater robustness against variations in image processing pipelines.
  • For Standard Space analysis, spatial normalization regularized by TPM is preferred; volumetric measurements are best performed in Native Space.

Related Concept Videos