| 1. |
- Velickaite, Vilma
(författare)
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Analysis of regional atrophy on brain imaging compared with cognitive function in the elderly and in patients with dementia – cross-sectional and longitudinal evaluation
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- During aging, brain changes are not homogeneous throughout the entire brain, but are related to changes in the morphology of neurons, as well as to changes in the tissue density, and are specific to each region of the brain. Dementia is a broad category of brain disorders with a set of symptoms including memory, visual-spatial and language problems. Most types of dementia are slowly progressing, and by the time the person shows signs of the disorder, processes in the brain are already advanced. Dementia reduces not only the person’s ability to perform everyday activities, it also increases mortality rates significantly. Because of the increasing incidence of dementia, possible prevention and treatment of dementia as early as possible are essential.The aim of the PhD project is to compare a quantitative and qualitative image analysis of regional cerebral atrophy with cognitive function in the elderly persons.In paper I, 58 persons participated (84–88 years old) from the ULSAM (Uppsala Longitudinal Study of Adult Men) cohort. They underwent CT of the brain, cognitive testing and LP. This study showed that AD biomarkers seem to be less informative in subjects with an advanced age.In papers II–IV, the cohort included subjects from the PIVUS (Prospective Investigation of the Vasculature in Uppsala Seniors) study.Paper II showed that at age 75, gender and education are confounders for MTA rating. Subjects with abnormal right MTA, but normal MMSE scores had developed worse MMSE scores 5 years later.Paper III showed that automated rating of MTA could be used in clinical practice to support the radiological evaluation. Automated rating of PA and F-GCA should be tested in future studies.In paper IV, we found a mild age-associated decrease in regional brain volumes in this healthy cohort with well-preserved cognitive and executive functions.In conclusion, the included studies in this thesis compare regional atrophy grades in the brain on CT and MRI and clinical data and provide knowledge that may be used in future investigations that aim to detect dementia in its early stages.
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| 2. |
- Georgiopoulos, Charalampos, 1984-
(författare)
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Imaging Studies of Olfaction in Health and Parkinsonism
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Olfactory loss is a common non-motor symptom of Parkinson’s disease (PD), often preceding the cardinal motor symptoms of the disease. The aim of this thesis was to: (a) evaluate whether olfactory examination can increase diagnostic accuracy, and (b) study the structural and functional neural basis of olfactory dysfunction in PD with different applications of Magnetic Resonance Imaging (MRI).Paper I was a comparison of the diagnostic accuracy between a simple smell identification test and DaTSCAN Single Photon Emission Computerized Tomography (SPECT), a nuclear medicine tomographic imaging technique that is commonly used in patients with suspected parkinsonism. The results indicate that smell test is inferior to DaTSCAN SPECT, but the combination of these two methods can lead to improved diagnostic accuracy.Paper II showed that diffusion MRI could detect discrete microstructural changes in the white matter of brain areas that participate in higher order olfactory neurotransmission, whereas MRI with Magnetization Transfer contrast could not.Paper III was a methodological study on how two different acquisition parameters can affect the activation pattern of olfactory brain areas, as observed with functional MRI (fMRI). The results indicate that brief olfactory stimulation and fast sampling rate should be preferred on olfactory fMRI studies.Paper IV used olfactory fMRI and resting-state fMRI in order to elucidate potentially altered activation patterns and functional connectivity within olfactory brain areas, between PD patients and healthy controls. Olfactory fMRI showed that olfactory impairment in PD is associated with significantly lower recruitment of the olfactory network. Resting-state fMRI did not detect any significant changes in the functional connectivity within the olfactory network of PD patients.In conclusion, the included studies provide evidence of: (a) disease-related structural and functional changes in olfactory brain areas, and (b) beneficial addition of olfactory tests in the clinical work-up of patients with parkinsonism.
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| 3. |
- Kockum, Karin, et al.
(författare)
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Standardized image evaluation in patients with idiopathic normal pressure hydrocephalus : consistency and reproducibility
- 2019
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Ingår i: Neuroradiology. - : Springer. - 0028-3940 .- 1432-1920. ; 61:12, s. 1397-1406
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: Assess the agreement for two investigators between computed tomography (CT) and magnetic resonance imaging (MRI) for seven imaging features included in the iNPH Radscale, a radiological screening tool.Methods: The study included 35 patients with idiopathic normal pressure hydrocephalus (iNPH) who were treated surgically from 2011 to 2015 at Uppsala University Hospital with preoperative CT and MRI performed with maximum 3 months between scans. Seven features were assessed: Evans’ index, temporal horn size, callosal angle, periventricular white matter changes, narrow high convexity sulci, focally enlarged sulci, and enlarged Sylvian fissures. All scans were assessed by two investigators who were blinded to each other’s results and to clinical data.Results: The agreement between CT and MRI was almost perfect for Evans’ index, temporal horns, narrow sulci, and Sylvian fissures (kappa and intraclass correlation, 0.84–0.91, p ≤ 0.001). There was substantial to almost perfect agreement for callosal angle and focally enlarged sulci. The concordance between modalities was fair for changes in periventricular white matter.Conclusion: CT and MRI are equally good for assessing radiological signs associated with iNPH except for periventricular white matter changes, as MRI has superior soft tissue contrast. The other imaging features can be evaluated consistently, and assessments are reproducible independent of modality. Therefore, the iNPH Radscale is applicable to both CT and MRI and may become an important tool for standardized evaluation in the workup in patients with suspected iNPH.
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