Radiology - Research Publications

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    Alterations in dorsal and ventral posterior cingulate connectivity in APOE ε4 carriers at risk of Alzheimer's disease
    Kerestes, R ; Phal, PM ; Steward, C ; Moffat, BA ; Salinas, S ; Cox, KL ; Ellis, KA ; Cyarto, EV ; Ames, D ; Martins, RN ; Masters, CL ; Rowe, CC ; Sharman, MJ ; Salvado, O ; Szoeke, C ; Lai, M ; Lautenschlager, NT ; Desmond, PM (ROYAL COLL PSYCHIATRISTS, 2015-10)
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    Baseline White Matter Is Associated With Physical Fitness Change in Preclinical Alzheimer's Disease
    Venkatraman, VK ; Steward, CE ; Cox, KL ; Ellis, KA ; Phal, PM ; Sharman, MJ ; Villemagne, VL ; Lai, MMY ; Cyarto, E ; Ames, D ; Szoeke, C ; Rowe, CC ; Masters, CL ; Lautenschlager, NT ; Desmond, PM (FRONTIERS MEDIA SA, 2020-04-29)
    White matter (WM) microstructure is a sensitive marker to distinguish individuals at risk of Alzheimer's disease. The association of objective physical fitness (PF) measures and WM microstructure has not been explored and mixed results reported with physical activity (PA). Longitudinal studies of WM with PA and PF measures have had limited investigation. This study explored the relationship between objective PF measures over 24-months with "normal-appearing" WM microstructure. Data acquired on magnetic resonance imaging was used to measure "normal-appearing" WM microstructure at baseline and 24-months. Clinical variables such as cognitive and blood-based measures were collected longitudinally. Also, as part of the randomized controlled trial of a PA, extensive measures of PA and fitness were obtained over the 24 months. Bilateral corticospinal tracts (CST) and the corpus callosum showed a significant association between PF performance over 24-months and baseline WM microstructural measures. There was no significant longitudinal effect of the intervention or PF performance over 24-months. Baseline WM microstructural measures were significantly associated with PF performance over 24-months in this cohort of participants with vascular risk factors and at risk of Alzheimer's disease with distinctive patterns for each PF test.
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    Incidence of cerebral microbleeds in preclinical Alzheimer disease
    Yates, PA ; Desmond, PM ; Phal, PM ; Steward, C ; Szoeke, C ; Salvado, O ; Ellis, KA ; Martins, RN ; Masters, CL ; Ames, D ; Villemagne, VL ; Rowe, CC (LIPPINCOTT WILLIAMS & WILKINS, 2014-04-08)
    OBJECTIVE: We sought to determine the incidence and associations of lobar microbleeds (LMBs) in a longitudinal cohort with (11)C-Pittsburgh compound B (PiB) PET imaging. METHODS: One hundred seventy-four participants from the observational Australian Imaging, Biomarkers and Lifestyle Study of Ageing (97 with normal cognition [NC], 37 with mild cognitive impairment [MCI], and 40 with Alzheimer disease [AD] dementia) were assessed at 3 time points over 3 years with 3-tesla susceptibility-weighted MRI and (11)C-PiB PET. MRIs were inspected for microbleeds, siderosis, infarction, and white matter hyperintensity severity, blind to clinical and PiB findings. Neocortical PiB standardized uptake value ratio, normalized to cerebellar cortex, was dichotomized as positive or negative (PiB+/-, standardized uptake value ratio >1.5). Annualized LMB incidence was calculated, and logistic regression was used to determine the association of incident LMBs with PiB, APOE ε4+ status, and cerebrovascular disease. RESULTS: LMBs were present in 18.6% of NC, 24.3% of MCI, and 40% of AD participants (p < 0.05 vs NC). LMB incidence was 0.2 ± 0.6 per year in NC participants, 0.2 ± 0.5 in MCI, and 0.7 ± 1.4 in AD (p < 0.03 vs NC) and was 6-fold higher in PiB+ than PiB-NC. Incident LMBs were associated with age, APOE ε4+, PiB+, and baseline LMBs. Incidence of multiple LMBs was also associated with lacunar infarction and white matter hyperintensity severity. CONCLUSIONS: Older age, baseline LMBs, higher β-amyloid burden, and concomitant cerebrovascular disease may all confer higher risk of incident LMBs. This should be considered when designing protocols for amyloid-modifying clinical trials.