| 1. |
- Lindberg, Olof, et al.
(författare)
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Hippocampal Shape Analysis in Alzheimer's Disease and Frontotemporal Lobar Degeneration Subtypes
- 2012
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Ingår i: Journal of Alzheimer's Disease. - 1387-2877 .- 1875-8908. ; 30:2, s. 355-365
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Tidskriftsartikel (refereegranskat)abstract
- Hippocampal pathology is central to Alzheimer's disease (AD) and other forms of dementia such as frontotemporal lobar degeneration (FTLD). Autopsy studies have shown that certain hippocampal subfields are more vulnerable than others to AD and FTLD pathology, in particular the subiculum and cornu ammonis 1 (CA1). We conducted shape analysis of hippocampi segmented from structural T1 MRI images on clinically diagnosed dementia patients and controls. The subjects included 19 AD and 35 FTLD patients [13 frontotemporal dementia (FTD), 13 semantic dementia (SD), and 9 progressive nonfluent aphasia (PNFA)] and 21 controls. Compared to controls, SD displayed severe atrophy of the whole left hippocampus. PNFA and FTD also displayed atrophy on the left side, restricted to the hippocampal head in FTD. Finally, AD displayed most atrophy in left hippocampal body with relative sparing of the hippocampal head. Consistent with neuropathological studies, most atrophic deformation was found in CA1 and subiculum areas in FTLD and AD.
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| 2. |
- Looi, Jeffrey C. L., et al.
(författare)
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Morphometric analysis of subcortical structures in progressive supranuclear palsy: In vivo evidence of neostriatal and mesencephalic atrophy
- 2011
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Ingår i: Psychiatry Research: Neuroimaging. - : Elsevier BV. - 0925-4927. ; 194:2, s. 163-175
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Tidskriftsartikel (refereegranskat)abstract
- Progressive supranuclear palsy (PSP) is a neurodegenerative disease characterized by gait and postural disturbance, gaze palsy, apathy, decreased verbal fluency and dysexecutive symptoms, with some of these clinical features potentially having origins in degeneration of frontostriatal circuits and the mesencephalon. This hypothesis was investigated by manual segmentation of the caudate and putamen on MRI scans, using previously published protocols, in 15 subjects with PSP and 15 healthy age-matched controls. Midbrain atrophy was assessed by measurement of mid-sagittal area of the midbrain and pons. Shape analysis of the caudate and putamen was performed using spherical harmonics (SPHARM-PDM, University of North Carolina). The sagittal pons area/midbrain area ratio (P/M ratio) was significantly higher in the PSP group, consistent with previous findings. Significantly smaller striatal volumes were found in the PSP group - putamina were 10% smaller and caudate volumes were 17% smaller than in controls after controlling for age and intracranial volume. Shape analysis revealed significant shape deflation in PSP in the striatum, compared to controls; with regionally significant change relevant to frontostriatal and corticostriatal circuits in the caudate. Thus, in a clinically diagnosed and biomarker-confirmed cohort with early PSP, we demonstrate that neostriatal volume and shape are significantly reduced in vivo. The findings suggest a neostriatal and mesencephalic structural basis for the clinical features of PSP leading to frontostriatal and mesocortical-striatal circuit disruption. (C) 2011 Elsevier Ireland Ltd. All rights reserved.
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| 3. |
- Looi, Jefferey Chee Leong, et al.
(författare)
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Shape analysis of the neostriatum in frontotemporal lobar degeneration, Alzheimer's disease, and controls
- 2010
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Ingår i: NeuroImage. - : Elsevier BV. - 1053-8119 .- 1095-9572. ; 51:3, s. 970-986
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Tidskriftsartikel (refereegranskat)abstract
- Background and purpose: Frontostriatal circuit mediated cognitive dysfunction has been implicated in frontotemporal lobar degeneration (FTLD), but not Alzheimer's disease, or healthy aging. We measured the neostriatum (caudate nucleus and putamen) volume in FTLD (n=34), in comparison with controls (n=27) and Alzheimer's disease (AD, n=19) subjects. Methods: Diagnoses were based on international consensus criteria. Manual bilateral segmentation of the caudate nucleus and putamen was conducted blind to diagnosis by a single analyst, on MRI scans using a standardized protocol. Intra-cranial volume was calculated via a stereological point counting technique and was used for scaling the shape analysis. The manual segmentation binaries were analyzed using UNC Shape Analysis tools (University of North Carolina) to perform comparisons among FTLD, AD, and controls for global shape, local p-value significance maps, and mean magnitude of shape displacement. Results: Shape analysis revealed that there was significant shape difference between FTLD, AD, and controls, consistent with the predicted frontostriatal dysfunction and of significant magnitude, as measured by displacement maps. There was a lateralized difference in shape for the left caudate for FTLD compared to AD; non-specific global atrophy in AD compared to controls; while FTLD showed a more specific pattern in regions relaying fronto- and corticostriatal circuits. Conclusions: Shape analysis shows regional specificity of atrophy, manifest as shape deflation, with implications for frontostriatal and corticostriatal motoric circuits, in FTLD, AD, and controls.
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| 4. |
- Looi, Jeffrey Chee Leong, et al.
(författare)
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Shape analysis of the neostriatum in subtypes of frontotemporal lobar degeneration : neuroanatomically significant regional morphologic change
- 2011
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Ingår i: Psychiatry Research. - : Elsevier BV. - 0925-4927 .- 1872-7506 .- 0165-1781. ; 191:2, s. 98-111
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Tidskriftsartikel (refereegranskat)abstract
- Frontostriatal circuit mediated cognitive dysfunction has been implicated in frontotemporal lobar degeneration (FTLD) and may differ across subtypes of FTLD. We manually segmented the neostriatum (caudate nucleus and putamen) in FTLD subtypes: behavioral variant frontotemporal dementia, FTD, n=12; semantic dementia, SD, n=13; and progressive non-fluent aphasia, PNFA, n=9); in comparison with controls (n=27). Diagnoses were based on international consensus criteria. Manual bilateral segmentation of the caudate nucleus and putamen was conducted blind to diagnosis by a single analyst, on MRI scans using a standardized protocol. Intracranial volume was calculated via a stereological point counting technique and was used for normalizing the shape analysis. Segmented binaries were analyzed using the Spherical Harmonic (SPHARM) Shape Analysis tools (University of North Carolina) to perform comparisons between FTLD subtypes and controls for global shape difference, local significance maps and mean magnitude maps of shape displacement. Shape analysis revealed that there was significant shape difference between FTLD subtypes and controls, consistent with the predicted frontostriatal dysfunction and of significant magnitude, as measured by displacement maps. These differences were not significant for SD compared to controls; lesser for PNFA compared to controls; whilst FTD showed a more specific pattern in regions relaying fronto- and corticostriatal circuits. Shape analysis shows regional specificity of atrophy, manifest as shape deflation, with a differential between FTLD subtypes, compared to controls.
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| 5. |
- Looi, Jeffrey C. L., et al.
(författare)
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The Australian, US, Scandinavian Imaging Exchange (AUSSIE): an innovative, virtually-integrated health research network embedded in health care
- 2014
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Ingår i: Australasian Psychiatry. - : SAGE Publications. - 1039-8562 .- 1440-1665. ; 22:3, s. 260-265
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To describe the development, design and function of an innovative international clinical research network for neuroimaging research, based in Australia, within a joint state health service/medical school. This Australian, US, Scandinavian Imaging Exchange (AUSSIE) network focuses upon identifying neuroimaging biomarkers for neuropsychiatric and neurodegenerative disease. Methods: We describe a case study of the iterative development of the network, identifying characteristic features and methods which may serve as potential models for virtual clinical research networks. This network was established to analyse clinically-derived neuroimaging data relevant to neuropsychiatric and neurodegenerative disease, specifically in relation to subcortical brain structures. Results: The AUSSIE network has harnessed synergies from the individual expertise of the component groups, primarily clinical neuroscience researchers, to analyse a variety of clinical data. Conclusion: AUSSIE is an active virtual clinical research network, analogous to a connectome, which is embedded in health care and has produced significant research, advancing our understanding of neuropsychiatric and neurodegenerative disease through the lens of neuroimaging.
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