Diss. (sammanfattning) Uppsala : Uppsala universitet, 2006. / Härtill 5 uppsatser.

Diss. (sammanfattning) Uppsala : Uppsala universitet, 2006. / Härtill 4 uppsatser.

Diss. (sammanfattning) Uppsala : Uppsala universitet, 2006. / Härtill 4 uppsatser.

Diss. (sammanfattning) Uppsala : Uppsala universitet, 2006. / Härtill 4 uppsatser.

Diss. (sammanfattning) Uppsala : Uppsala universitet, 2006. / Härtill 5 uppsatser.

Quantitative assessment of myocardial function is a valuable tool for clinical applications and physiological studies. This assessment can be acquired using phase based motion sensitive magnetic resonance imaging (MRI) techniques. In this thesis, the accuracy of these phase based motion sensitive MRI techniques is investigated, and modifications in acquisition and post-processing are proposed. The strain rate of the myocardium can be used to evaluate the myocardial function. However, the estimation of strain rate from the velocity data acquired with phase-contrast MRI (PC-MRI) is sensitive to noise. Estimation using normalized convolution showed, however, to reduce this sensitivity to noise and to minimize the influence of non-myocardial tissue which could impair the result. Strain of the myocardium is another measure to assess myocardial function. Strain can be estimated from the myocardial displacement acquired with displacement encoding with stimulated echo (DENSE). DENSE acquisition can be realized with several different encoding strategies. The choice of encoding scheme may make the acquisition more or less sensitive to different sources of error. Two potential sources of errors in DENSE acquisition are the influence of the FID and of  the off-resonance effects. Their influence on DENSE were investigated to determine suitable encoding strategies to reduce their influence and thereby improve the measurement accuracy acquired. The quality of the DENSE measurement is not only dependent on the accuracy, but also the precision of the measurement. The precision is affected by the SNR and thereby depends on flip angle strategies, magnetic field strength and spatial variation of the receiver coil sensitivity. A mutual comparison of their influence on SNR in DENSE was therefore performed and could serve as a guideline to optimize parameters for specific applications. The acquisition time is often an important factor, especially in clinical applications where it affects potential patient discomfort and patient through-put. A multiple-slice DENSE acquisition was therefore presented, which allows the acquisition of strain values according to the 16-segment cardiac model within a single breath-hold, instead of the conventional three breath-holds. The DENSE technique can also be adapted toward comprehensive evaluation of the heart in the form of full three-dimensional three-directional acquisition of the displacement. To estimate the full strain tensor from these data, a novel post-processing technique using a polynomial was investigated. The method yielded accurate results on an analytical model and \textit{in-vivo} strains obtained agreed with previously reported myocardial strains in normal volunteers.

Bakgrund: Medicinsk turism har under det senaste åren växt fram som en ny nischturism. Den medicinska turismen har etablerat sig utomlands men inte riktigt i Sverige, vilket gör att det är intressant att studera svenskars intresse för medicinsk turism. Syfte: Syftet med den här uppsatsen har varit att undersöka vilka faktorer som blir viktigast för att svenskar skulle kunna resa för medicinsk turism utomlands eller i Sverige. Frågeställning: Den frågeställning som den här uppsatsen har ställt är: Vilka faktorer spelar in vid valet av att resa utomlands eller i Sverige för medicinsk turism? Metod: Uppsatsen har använt sig av en kvantitativ enkätundersökning där Sapfords tumregel om att en enkätundersökning minst skall innehålla 40 respondenter har tillämpats. I enkätundersökningen tillfrågades 70 svenska respondenter varav 68 enkäter användes i studien på grund av bortfall på två enkäter som hade ofullständiga svar. Slutsatser:Svenskarna i den här studien var positiva till medicinsk turism. Respondenterna skulle till stor del kunna tänka sig att resa både utomlands och i Sverige. 71,2% skulle föredra att resa inom Sverige medan ett något lägre andel skulle kunna tänka sig att resa utomlands för vård. De faktorer som spelade in vid valet av att resa utomlands eller i Sverige för medicinsk turism blev totalt sju faktorer, som respondenterna graderade som viktigast. De första tre var gemensamma för utomlands och Sverige var: Läkare och annan vårdpersonal är certifierade inom sitt yrke/specialitet Kvaliten/hygienen inom vården Det finns regler och standarder för behandling av patienter Av de återstående fyra faktorerna så behandlade två stycken medicinsk turism utomlands: Standarden utomlands på vården är bättre eller lika bra som i Sverige Landet ska ha ett politiskt stabilt klimat Av de återstående fyra faktorerna så behandlade två medicinsk turism i Sverige Möjlighet att få eftervård i hemkommunen För att Sverige har en god och stabil ekonomi Resultatet kan tolkas som att svenskar föredrar att resa inom Sverige för medicinsk turism därför att Sverige har ett politiskt, ekonomiskt och socialt etablerat trygghetsystem som till skillnad från valet av att resa  för medicinsk turism utomlands är mer osäkert och kräver mer information och kunskap innan man väljer detta alternativ. Svenskar är ändå positiva till att resa utomlands för vård och mer information om säkerhetsaspekter och vårdkvaliten skulle kunna öka intresset och andelen positiva. / Background: Medical tourism has over the past few years emerged as a new niche tourism. The medical tourism has become established abroad but not quite as much in Sweden, which makes it interesting to study the Swedes' interest in medical tourism. Purpose: The purpose of this essay is to study medical tourism from a Swedish perspective, and focuses on the factors that will be important for medical tourism. Research question: The question that this paper has pointed out is: What factors come into play when choosing to travel abroad or in Sweden for medical tourism? Method: The essay has used mixed methods, which consisted of a quantitative survey where Sapsfords rule says that a survey should contain at least a minimum level of 40 respondents in a survey study. In the survey 70 Swedish respondents were asked of which 68 surveys where used because of two questioners that had incomplete answers was removed. Conclusions: Swedes in this study were positive to medical tourism. Respondents were largely willing to travel both outside and within the country of Sweden. 71.2% would prefer to travel in Sweden while a slightly lower percentage 46%, would be willing to travel abroad for choice. The factors that played into the choice of travelling abroad or in Sweden for medical tourism was a total of seven factors that the respondents rated as most important. The first three, which were equivalent for abroad and Sweden were: Physicians and other health professionals are certified in their profession / speciality The quality / hygiene in health care There are rules and standards for the treatment of patients Of the remaining four factors two dealt whit medical tourism abroad: The country's political climate should be stable so that patient safety is not affected There should be the same or higher standard of the medical care than in Sweden Of the remaining four factors two dealt whit medical tourism in Sweden: Possibility to get the aftercare in the home municipality Sweden has a strong and stable economy The result can be interpreted that Swedes prefer to travel in Sweden for medical tourism because Sweden has political, economic and social security systems established that unlike the choice in travelling abroad for medical tourism is more uncertain and require more information and knowledge before choosing that option. Swedes are still positive about travelling abroad for medical care and more information about the safety and quality of care could increase the interest and the percentage of the positive towards travelling abroad for medical tourism.

Laser Doppler flowmetry (LDF) is virtually the only non-invasive technique, except for other laser speckle based techniques, that enables estimation of the microcirculatory blood flow. The technique was introduced into the field of biomedical engineering in the 1970s, and a rapid evolvement followed during the 1980s with fiber based systems and improved signal analysis. The first imaging systems were presented in the beginning of the 1990s. Conventional LDF, although unique in many aspects and elegant as a method, is accompanied by a number of limitations that may have reduced the clinical impact of the technique. The analysis model published by Bonner and Nossal in 1981, which is the basis for conventional LDF, is limited to measurements given in arbitrary and relative units, unknown and non-constant measurement volume, non-linearities at increased blood tissue fractions, and a relative average velocity estimate. In this thesis a new LDF analysis method, quantitative LDF, is presented. The method is based on recent models for light-tissue interaction, comprising the current knowledge of tissue structure and optical properties, making it fundamentally different from the Bonner and Nossal model. Furthermore and most importantly, the method eliminates or highly reduces the limitations mentioned above. Central to quantitative LDF is Monte Carlo (MC) simulations of light transport in tissue models, including multiple Doppler shifts by red blood cells (RBC). MC was used in the first proof-of-concept study where the principles of the quantitative LDF were tested using plastic flow phantoms. An optically and physiologically relevant skin model suitable for MC was then developed. MC simulations of that model as well as of homogeneous tissue relevant models were used to evaluate the measurement depth and volume of conventional LDF systems. Moreover, a variance reduction technique enabling the reduction of simulation times in orders of magnitudes for imaging based MC setups was presented. The principle of the quantitative LDF method is to solve the reverse engineering problem of matching measured and calculated Doppler power spectra at two different source-detector separations. The forward problem of calculating the Doppler power spectra from a model is solved by mixing optical Doppler spectra, based on the scattering phase functions and the velocity distribution of the RBC, from various layers in the model and for various amounts of Doppler shifts. The Doppler shift distribution is calculated based on the scattering coefficient of the RBC:s and the path length distribution of the photons in the model, where the latter is given from a few basal MC simulations. When a proper spectral matching is found, via iterative model parameters updates, the absolute measurement data are given directly from the model. The concentration is given in g RBC/100 g tissue, velocities in mm/s, and perfusion in g RBC/100 g tissue × mm/s. The RBC perfusion is separated into three velocity regions, below 1 mm/s, between 1 and 10 mm/s, and above 10 mm/s. Furthermore, the measures are given for a constant output volume of a 3 mm3 half sphere, i.e. within 1.13 mm from the light emitting fiber of the measurement probe. The quantitative LDF method was used in a study on microcirculatory changes in type 2 diabetes. It was concluded that the perfusion response to a local increase in skin temperature, a response that is reduced in diabetes, is a process involving only intermediate and high flow velocities and thus relatively large vessels in the microcirculation. The increased flow in higher velocities was expected, but could not previously be demonstrated with conventional LDF. The lack of increase in low velocity flow indicates a normal metabolic demand during heating. Furthermore, a correlation between the perfusion at low and intermediate flow velocities and diabetes duration was found. Interestingly, these correlations were opposites (negative for the low velocity region and positive for the mediate velocity region). This finding is well in line with the increased shunt flow and reduced nutritive capillary flow that has previously been observed in diabetes.

Litteraturstudier har genomförts med syftet att utveckla minst en ny detektionsmetod som skulle kunna ersätta den metod som företaget Cavidi använder sig av idag. Cavidi hade specificerat krav som metodförslaget skulle uppfylla. Dessa krav var att metoden skulle vara snabb, lättanvänd, billig, ha hög känslighet och kunna förvaras i rumstemperatur. Två lovande metoder som baseras på två olika principer valdes ut. Den ena metoden bygger på att enkelsträngat DNA med en specifik nukleinsyrakomposition syntetiseras. Denna sekvens har egenskapen att spontant bilda en sekundärstruktur som kan bilda komplex med en fluorofor. Detta ökar dess fluorescens. Ökningen detekteras med fluorescensspektroskopi. Den andra metoden baseras på ett optomagnetiskt fenomen vilket innebär att ett magnetiskt fält påverkas av polariserat ljus. Metoden går ut på att virioner först renas fram från blodplasma och att de fäster på jonbytarkulor under rådande buffertförhållanden. Magnetiska nanopartiklar tillsätts som binder till jonbytarkulornas lediga ytor. Om många virioner har bundit till jonbytarkulorna finns det en större mängd fria nanopartiklar i lösningen. Antalet fria nanopartiklar i lösningen är proportionellt mot mängden HIV i provet och kan då detekteras med en fotodetektor. Fördelarna med dessa metoder är att processen blir billigare, snabbare och har en hög känslighet. Metoderna är lättanvända och använder färre komponenter jämfört med Cavidis nuvarande metod. Därmed blir Cavidis produkter billigare och tillgängliga för fler människor.

Denna rapport kommer att visa på hur utvecklingen av en prototyp för lagring av fysiska rörelser har gått till. Vilka komponenter som har valts och varför. Arbetet är utfört på uppdrag av Medicinsk Teknik – Forskning och Utveckling (MT-FoU) vid Umeå Universitet i Sverige. MT-FoU har även bistått med mjukvara och möjligheten till 3D-utskrift av behållare för prototypen. Prototypen kan lagra information om rörelser med hjälp av accelerometer, gyroskop och magnetometer. Informationen lagras på ett SD-kort och överförs sedan trådlöst via en nätverksrouter till klientsidan medhjälp av WiFi. Fysisk aktivitet har visat sig vara en viktigare del av människans hälsa än tidigare trott. Därför är det alltid viktigt att röra på sig mycket men och på rätt sätt. Med hjälp av denna produkt kan information om hur du exempelvis rör dig under ett träningspass registreras och analyseras. I denna rapport tas tillförlitligheten upp hos produkten med hjälp av två andra kommersiella produkter som data jämförs mot. / This report will show how the development of a prototype for the storage of physical movements has been developed. Which components that have been chosen and why. The work is performed on behalf of the Biomedical Engineering - Research and Development (MT-FoU) at Umeå University, Sweden. MT-FoU has also assisted with the software and the possibility of 3D printing of containers for the prototype. The prototype can store information about movement using the accelerometer, gyroscope and magnetometer. The information is stored on an SD card and then transmitted wirelessly via a network router to the clientside using WiFi. Physical activity has been shown to be a more important part of human health than previously thought. It´s always important to move much but it´s also important that we move in a right way as well. With the help of this product information on moves during a training session is recorded and analyzed. In this report, the reliability of the product is measured with the help of two other commercial products which data is compared against.