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Neuroimage Clin. 2018;20:851-860. doi: 10.1016/j.nicl.2018.09.013. Epub 2018 Sep 19.

Voxel-wise deviations from healthy aging for the detection of region-specific atrophy.

Author information

1
University Hospital of Old Age Psychiatry, University of Bern, Bern, Switzerland; Freiburg Brain Imaging Center, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Germany; Center of Geriatrics and Gerontology Freiburg, University Medical Center Freiburg, Germany; Department of Psychiatry and Psychotherapy, University Medical Center, Freiburg, Germany. Electronic address: stefan.kloeppel@upd.unibe.ch.
2
Dept. of Neuroradiology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Germany.
3
Center of Geriatrics and Gerontology Freiburg, University Medical Center Freiburg, Germany.
4
Neuroradiology, University Hospital Carl Gustav Carus, Dresden, Germany; Neurology, University Hospital Carl Gustav Carus, Dresden, Germany.
5
Department of Neurology, Sankt Katharinen Hospital, Teaching Hospital of the Goethe University, Frankfurt, Germany; Institute of Neuroradiology,Goethe University Frankfurt, Germany.
6
Department of Psychiatry and Psychotherapy, University Medical Center, Freiburg, Germany.
7
Freiburg Brain Imaging Center, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Germany; Department of Psychiatry and Psychotherapy, University Medical Center, Freiburg, Germany.
8
Department of Nuclear Medicine, University Medical Center Freiburg, Faculty of Medicine, University of Freiburg, Germany.
9
University Hospital of Old Age Psychiatry, University of Bern, Bern, Switzerland.
10
University Hospital of Old Age Psychiatry, University of Bern, Bern, Switzerland; Freiburg Brain Imaging Center, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Germany; Department of Computer Science, University of Freiburg, Germany.
11
Department of Nuclear Medicine, University Medical Center Freiburg, Faculty of Medicine, University of Freiburg, Germany; Department of Psychiatry and Psychotherapy, University Medical Center, Freiburg, Germany.
12
Freiburg Brain Imaging Center, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Germany; Dept. of Neuroradiology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Germany.

Abstract

The identification of pathological atrophy in MRI scans requires specialized training, which is scarce outside dedicated centers. We sought to investigate the clinical usefulness of computer-generated representations of local grey matter (GM) loss or increased volume of cerebral fluids (CSF) as normalized deviations (z-scores) from healthy aging to either aid human visual readings or directly detect pathological atrophy. Two experienced neuroradiologists rated atrophy in 30 patients with Alzheimer's disease (AD), 30 patients with frontotemporal dementia (FTD), 30 with dementia due to Lewy-body disease (LBD) and 30 healthy controls (HC) on a three-point scale in 10 anatomical regions as reference gold standard. Seven raters, varying in their experience with MRI diagnostics rated all cases on the same scale once with and once without computer-generated volume deviation maps that were overlaid on anatomical slices. In addition, we investigated the predictive value of the computer generated deviation maps on their own for the detection of atrophy as identified by the gold standard raters. Inter and intra-rater agreements of the two gold standard raters were substantial (Cohen's kappa κ > 0.62). The intra-rater agreement of the other raters ranged from fair (κ = 0.37) to substantial (κ = 0.72) and improved on average by 0.13 (0.57 < κ < 0.87) when volume deviation maps were displayed. The seven other raters showed good agreement with the gold standard in regions including the hippocampus but agreement was substantially lower in e.g. the parietal cortex and did not improve with the display of atrophy scores. Rating speed increased over the course of the study and irrespective of the presentation of voxel-wise deviations. Automatically detected large deviations of local volume were consistently associated with gold standard atrophy reading as shown by an area under the receiver operator characteristic of up to 0.95 for the hippocampus region. When applying these test characteristics to prevalences typically found in a memory clinic, we observed a positive or negative predictive value close to or above 0.9 in the hippocampus for almost all of the expected cases. The volume deviation maps derived from CSF volume increase were generally better in detecting atrophy. Our study demonstrates an agreement of visual ratings among non-experts not further increased by displaying, region-specific deviations of volume. The high predictive value of computer generated local deviations independent from human interaction and the consistent advantages of CSF-over GM-based estimations should be considered in the development of diagnostic tools and indicate clinical utility well beyond aiding visual assessments.

PMID:
30278372
PMCID:
PMC6169102
DOI:
10.1016/j.nicl.2018.09.013
[Indexed for MEDLINE]
Free PMC Article

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