Medizinische Universität Graz Austria/Österreich - Forschungsportal - Medical University of Graz
Gewählte Publikation:
Colonna, I.
Magnetization Transfer Imaging: a non-conventional MRI technique for the longitudinal assessment of Alzheimer's disease
Doktoratsstudium der Medizinischen Wissenschaft; Humanmedizin; [ Dissertation ] Medical University of Graz; 2021. pp. 104
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- Autor*innen der Med Uni Graz:
- Betreuer*innen:
- Deutschmann Hannes
- Langkammer Christian
- Schmidt Reinhold
- Altmetrics:
- Abstract:
- Background Magnetization Transfer Imaging can detect microstructural brain tissue changes that are not assessable by conventional magnetic resonance imaging and may be helpful in Alzheimer´s disease (AD) diagnosis. The aim of the present thesis was to compare magnetization transfer ratio (MTR) measures in global and regional grey and white matter between individuals with Alzheimer´s disease and healthy control participants, to analyze the relationship between MTRs and cognitive functioning in AD, and to investigate the MTR changes and their association with cognitive decline after a follow-up time in AD. Material and methods In this prospective study, participants with Alzheimer disease and a group of age-matched healthy controls underwent clinical examinations and 3T MRI. MTRs were determined in the cortex, in six areas that have been seen to be particularly vulnerable to AD, namely the “AD-signature regions”, in the normal-appearing white matter, and in the white matter hyperintensities. The cognitive function was assessed in AD patients with Mini Mental State Examination and the Consortium to Establish a Registry for Alzheimer Disease test battery. Statistical analysis were performed with SPSS 25. Results Seventy-seven study participants (mean age ± SD, 72 ± 8 years; 47 female) and seventy-seven age-matched healthy control participants (mean age ± SD, 72 ± 8 years; 44 female) were evaluated. MTR values were lower in subjects with AD than in healthy control participants in all investigated regions. When adjusting for atrophy and extent of white matter hyperintensities, AD diagnosis related significantly to lower MTRs in global cortex (OR = 0.47; 95% CI: 0.22, 0.97; P = 0.04), in AD signature regions (OR= 0.31; 95% CI: 0.14, 0.67; P = 0.003), in normal-appearing white matter (OR = 0.59; 95% CI: 0.39, 0.88; P = 0.01) and in white matter hyperintensities (OR = 0.18; 95% CI: 0.09, 0.33; P < 0.001). Further, lower grey matter MTRs were associated with poorer global cognition, language function, and constructional praxis in AD. Forty-seven patients of the AD cohort underwent a subsequent clinical, neuropsychological and neuroimaging assessment after a follow-up time (mean years ± SD = 1.06 years ± 0.24). In the longitudinal analysis, a significant MTR decline over time was seen only in the global cortex (annualized MTR change: median = -3.86, P < 0.001); however, it not related to cognitive decline. Conclusions Alzheimer disease is associated with MTR reductions in grey and white matter regions of the brain. Lower MTRs in the entire cortex and AD-signature regions contribute to cognitive impairment in AD, independent of brain atrophy and white matter damage. Only cortical MTRs declined significantly over the follow-up time in AD.