Temporal trajectory and progression score estimation from voxelwise longitudinal imaging measures: Application to amyloid imaging

Murat Bilgel, Bruno Jedynak, Dean F. Wong, Susan M. Resnick, Jerry L. Prince

Research output: Contribution to journalConference articlepeer-review

10 Scopus citations

Abstract

Cortical β-amyloid deposition begins in Alzheimer’s disease (AD) years before the onset of any clinical symptoms. It is therefore important to determine the temporal trajectories of amyloid deposition in these earliest stages in order to better understand their associations with progression to AD. A method for estimating the temporal trajectories of voxelwise amyloid as measured using longitudinal positron emission tomography (PET) imaging is presented. The method involves the estimation of a score for each subject visit based on the PET data that reflects their amyloid progression. This amyloid progression score allows subjects with similar progressions to be aligned and analyzed together. The estimation of the progression scores and the amyloid trajectory parameters are performed using an expectation-maximization algorithm. The correlations among the voxel measures of amyloid are modeled to reflect the spatial nature of PET images. Simulation results show that model parameters are captured well at a variety of noise and spatial correlation levels. The method is applied to longitudinal amyloid imaging data considering each cerebral hemisphere separately. The results are consistent across the hemispheres and agree with a global index of brain amyloid known as mean cortical DVR. Unlike mean cortical DVR, which depends on a priori defined regions, the progression score extracted by the method is data-driven and does not make assumptions about regional longitudinal changes. Compared to regressing on age at each voxel, the longitudinal trajectory slopes estimated using the proposed method show better localized longitudinal changes.

Original languageEnglish
Pages (from-to)424-436
Number of pages13
JournalLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Volume9123
DOIs
StatePublished - 2015
Event24th International Conference on Information Processing in Medical Imaging, IPMI 2015 - Isle of Skye, United Kingdom
Duration: Jun 28 2015Jul 3 2015

Keywords

  • Amyloid
  • Longitudinal image analysis
  • PiB
  • Pittsburgh compound B
  • Progression score

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