SAMMANFATTNING Bakgrund: Vid hjärnundersökningar finns även andra strukturer utanför hjärnan som är innerverade av nervsystemet. Det är möjligt att sjukdomen i hjärnan avspeglas där också. Det finns många sjukdomar och tillstånd med liknande symptom och att ställa rätt diagnos kan vara svårt. Många sjukdomar påverkar det autonoma nervsystemet och ett sätt att hitta rätt diagnos kan vara att undersöka hur det fungerar.  Syfte: Att se vilka variationer av radioaktivitetsupptag som fanns i parotiskörtlarna mellan patienterna som avbildades med 11C-PE2I PET/DT. Samt att kunna se om denna information kan utnyttjas till att identifiera dysfunktion av autonoma nervsystemet (MRT-bilder är även en tillhjälps verktyg). Metod: Studiedesignen var en retrospektiv kvantitativ studie. Hundra (konsekutiva) patienter indelades i grupper så som: normal, Parkinsons, Parkinsons sjukdom med kombination av vaskulära förändringar och atypisk Parkinson sjukdom. Isotopupptag i basala ganglier och parotiskörtlar har mätts. Några patienters MRT- bilder var tillgängligt till kvantifiering.   Resultat: kombinerade gruppen med Parkinsons sjukdom, atypisk Parkinsons sjukdom och vaskulära förändringar har en uppreglering av antalet fria dopaminreceptorer i parotis jämfört med friska (även i bara PSP samt bara vaskulära grupper) med (p <0.05).   Slutsats: Det finns variation av upptaget mellan en del av grupper därmed kan sjukdomen i hjärnan avspeglas i körtlar också.   Nyckelord: Neurodegenerativa sjukdomar, Autonom dysfunktion, 11CPE2I-PET/DT, parotiskörtlar, basala ganglier / ABSTRACT Background: At brain examination, there are also other structures outside the brain that are innervated by the nervous system. It is possible that the disease of the brain is reflected there as well. There are many diseases and conditions with similar symptoms and making the right diagnosis can be difficult. Many diseases affect the autonomic nervous system and one way to find the right diagnosis may be to investigate how it works.     Purpose: to see what variations in radioactivity uptake were found in the parotic glands between the patients depicted with the 11C-PE2I PET/CT. As well as being able to see how valuable this information is in being used to identify dysfunction of the autonomic nervous system (MRT- images are also an aids tool).   Method: The study design was a retrospective quantitative study. One hundred (consecutive) patients were divided in groups such as normal, Parkinson's, Parkinson's disease with combination of vascular changes and atypical Parkinson's disease. Isotope uptake in basal ganglia and parotic glands has been measured. Some patients' MRT images were available for quantification.     Result: the results show that the combined group of Parkinson's disease, atypical Parkinson's disease and vascular changes has an upregulation of the number of free dopamine receptors in parotid compared to healthy ones (also in PSP only and only vascular groups) with (p <0.05).    Conclusion: There is variation of uptake between some of the groups thus the disease in the brain can be reflected in glands as well.     Keywords: Neurodegenerative Diseases, Autonomic Dysfunction, 11CPE2I-PET/CT, Parotid Glands, Basal Ganglia

Applying mathematical models to dynamic contrast enhanced MRI (DCE MRI) data to perform quantitative tracer kinetic analysis enables the estimation of tissue characteristics such as vascular permeability and the fractional volume of plasma in a tissue. However, it is unclear to what extent modeling assumptions, particularly regarding water exchange between tissue compartments, impacts parameter estimates derived from clinical DCE MRI data. In this work, a new model is developed which includes water exchange effects, termed the water exchange modified two compartment exchange model (WX-2CXM). Two boundaries of this model (the fast and no exchange limits) were used to analyse a clinical DCE MRI bladder cancer dataset. Comparisons with DCE CT, which is not affected by water exchange, suggested that water exchange may have affected estimates of vp, the fractional volume of plasma. Further investigation and simulations led to the development of a DCE MRI protocol which was sensitised to water exchange, in order to further evaluate the water exchange effects found in the bladder cancer dataset. This protocol was tested by imaging the parotid glands in eight healthy volunteers, and confirmed evidence of water exchange effects on vp, as well as flow Fp and the fractional volume of extravascular extracellular space ve. This protocol also enabled preliminary estimates of the water residence times in parotid tissue, however, these estimates had a large variability and require further validation. The work presented in this thesis suggests that, although water exchange effects do not have a large effect on clinical data, the effect is measurable, and may lead to the ability to estimate of tissue water residence times. Results do not support a change in the current practise of neglecting water exchange effects in clinical DCEMRI acquisitions.

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