Multimodal Imaging of Cerebral Amyloid and Tau

All participants underwent simultaneous three-dimensional (3D) [¹¹C] Pittsburg compound B (PiB)-PET and 3D T1-weighted MRI using the 3.0T Biograph mMR (PET-MR) scanner (Siemens, Washington DC, USA) at both the initial assessment and 2-year follow-up (Fig. 1). The image processing was conducted utilizing SPM8. An automatic anatomic labeling algorithm and a region combining method were applied to identify specific regions of interests (ROIs) [29 , 30 (link)]. To quantify the extent of cerebral Aβ deposition, the uptake value of [¹¹C] PiB was extracted from ROIs encompassing the frontal, lateral parietal, posterior cingulate-precuneus, and lateral temporal regions. The calculation of the voxel-weighted mean standardized uptake value ratio (SUVR) for these ROIs was achieved by dividing the mean [¹¹C] PiB uptake value of these ROIs by the corresponding mean uptake values of cerebrum white matter, cerebellar white matter, pons and inferior cerebellar gray matter regions [31 (link)–33 (link)]. More detailed information about the methodology used for measuring cerebral Aβ deposition can be found in a prior publication [21 (link)].
Fig. 1

Datasets for analysis. Dataset for analysis of association between Aβ or Tau deposition and WMH volume. Aβ = Beta-amyloid, WMH = White matter hyperintensity. A = Aβ-PET, M = MRI scan, T = Tau-PET