Locus coeruleus imaging as a biomarker for noradrenergic dysfunction in neurodegenerative diseases

Pathological alterations to the locus coeruleus, the major source of noradrenaline in the brain, are histologically evident in early stages of neurodegenerative diseases. Novel MRI approaches now provide an opportunity to quantify structural features of the locus coeruleus in vivo during disease progression. In combination with neuropathological biomarkers, in vivo locus coeruleus imaging could help to understand the contribution of locus coeruleus neurodegeneration to clinical and pathological manifestations in Alzheimer’s disease, atypical neurodegenerative dementias and Parkinson’s disease. Moreover, as the functional sensitivity of the noradrenergic system is likely to change with disease progression, in vivo measures of locus coeruleus integrity could provide new pathophysiological insights into cognitive and behavioural symptoms. Locus coeruleus imaging also holds the promise to stratify patients into clinical trials according to noradrenergic dysfunction. In this article, we present a consensus on how non-invasive in vivo assessment of locus coeruleus integrity can be used for clinical research in neurodegenerative diseases. We outline the next steps for in vivo, post-mortem and clinical studies that can lay the groundwork to evaluate the potential of locus coeruleus imaging as a biomarker for neurodegenerative diseases

Automatic segmentation of the striatum and globus pallidus using MIST: Multimodal Image Segmentation Tool

Accurate segmentation of the subcortical structures is frequently required in neuroimaging studies. Most existing methods use only a T1-weighted MRI volume to segment all supported structures and usually rely on a database of training data. We propose a new method that can use multiple image modalities simultaneously and a single reference segmentation for initialisation, without the need for a manually labelled training set. The method models intensity profiles in multiple images around the boundaries of the structure after nonlinear registration. It is trained using a set of unlabelled training data, which may be the same images that are to be segmented, and it can automatically infer the location of the physical boundary using user-specified priors. We show that the method produces high-quality segmentations of the striatum, which is clearly visible on T1-weighted scans, and the globus pallidus, which has poor contrast on such scans. The method compares favourably to existing methods, showing greater overlap with manual segmentations and better consistency

Environmental health guideline for Municipal Public Health Services : Mercury in the indoor environment and health

Het RIVM heeft, in opdracht van het ministerie van VWS, met de GGD'en de richtlijn 'Kwik in het binnenmilieu en gezondheid' ontwikkeld. Hoewel de verkoop van de meeste kwikhoudende producten is verboden, blijven kwikincidenten mogelijk als oude, kwikhoudende, producten breken en daarbij vloeibare kwik vrijkomt. Hierdoor hebben GGD-medewerkers medische milieukunde behoefte aan informatie over de blootstellingsbepaling, de gezondheidskundige advieswaarden en de opruimprocedure na kwikincidenten. Kwikzilver, zoals vloeibaar kwik ook wel wordt genoemd, heeft meer negatieve effecten op de gezondheid dan de meeste mensen vermoeden en is daardoor een onderschat probleem. Langdurige blootstelling aan lage concentraties kwikdamp kan leiden tot ernstige gezondheidseffecten. Mensen kunnen gedurende langere tijd aan kwikdamp blootgesteld worden als kwik binnenshuis achterblijft na breuk van een kwikhoudend product. Een kleine hoeveelheid kwik kan gemakkelijk achterblijven in de vloerbedekking of in een kier, hoewel het lijkt alsof alles is verwijderd. Het doel van deze richtlijn is GGD-medewerkers achtergrondinformatie te geven en een handvat te bieden bij het beoordelen van kwikincidenten. De richtlijn geeft de benodigde informatie voor een zorgvuldige risicoanalyse en geeft adviezen over te nemen maatregelen. Een stappenplan is ontwikkeld als hulpmiddel bij de behandeling van een kwikincident. Tevens worden de mogelijkheden besproken om kwikincidenten in het binnenmilieu te voorkomen door bijvoorbeeld voorlichting te geven of door het inwisselen van thermometers aan te bieden. In de bijlagen staan voorbeeldteksten voor voorlichtingsdoeleinden.Although the sale of most mercury containing products is prohibited, mercury spills are still possible as old, mercury containing, products may break and release liquid mercury. Therefore, environmental health workers at the Municipal Public Health Services (GGD) need information concerning exposure assessment, health-based guideline values and clean-up procedures after mercury spills. For this purpose, the Ministry of Health, Welfare and Sport (VWS) commissioned the National Institute for Public Health and the Environment (RIVM) and the Municipal Public Health Services (GGD) to draw up a guideline on mercury in the indoor environment and health. Exposure to mercury leads to more adverse health effects than most people anticipate and is therefore an underestimated problem. Long-term exposure to low concentrations of mercury vapour can lead to serious health effects. People can be exposed to mercury vapour for a long time if traces of mercury remain indoors after breakage of a mercury containing product. Traces of mercury can easily be left unseen in floor carpeting or in a small crack after apparent cleaning. This guideline is aimed at providing Municipal Public Health Service workers with background information and it is an instrument for assessing mercury spills. The guideline provides the information required for a careful risk assessment and gives advice on measures to be taken. A step-by-step plan has been developed as guidance for the assessment of mercury spills. Possibilities to prevent mercury spills indoors are discussed, such as facilitating the exchange of mercury containing thermometers and providing information and education. The appendices contain example letters for education and information purposes.VW