An arthroscope is a diagnostic instrument for visualisation of the interior of a joint. By adding a laser to an arthroscope and feeding the images to a computer, one gets an method to measure the structure of the cartilage covering the joint. This gives an added diagnostic value. The laser will create laser speckles and this report covers the basic theories behind this. The anatomy of the joints, the properties of cartilage and the background on the disease arthritis are also covered, as well as the field of surface topography and image processing. Experiments were performed on three different materials - metals of different definite surface roughness, polymerised collagen and bovine articular cartilage. The conclusion is that the technique would work, providing that some obstacles could be overcome. The technique itself is very precise and detects nanometric differences in the surface structure, making it extremely interesting for research purposes, such as follow-ups on treatments and studies of arthritis and cartilage repair.

The cardiac wall has complex three-dimensional fiber structures and mechanical properties that enable the heart to efficiently pump the blood through the body. By studying the myocardial strains induced during diastole, information about the pumping performance of the heart and what mechanisms that are responsible for this effective blood filling, can be achieved. Two different computation methods for myocardial strain, both based on data acquired from marker technique, were compared using a theoretical cylinder model. The non-homogeneous polynomial fitting method yielded higher accuracy than a homogeneous tetrahedron method, and was further used to investigate cardiac and fiber strains at different wall depths and myocardial regions in normal and ischemic ovine hearts. Large spatial and regional variations were found, as well as alterations, conveyed by ischemic conditions, of fiber mechanisms responsible for the circumferential expansion and wall thinning during diastole.

<p>Ventricular Assist Devices (VADs) are mechanical pumps used to off-load a deceased heart, primarily in late stage congestive heart failure patients. VAD employment may facilitate cardiac recovery, but most often provides time before a suitable heart transplant can be found. Lately, long term use VAD systems have been introduced as an alternative to a heart transplant.</p><p>Traditionally, design of VADs has employed either displacement based pump technologies or radial-flow pumps, also known as rotodynamic pumps. A displacement pump induces a mechanical force on a fluid contained within a defined space, hence giving it motion. Radial-flow pumps impart momentum to a fluid, most often by placing a rotating device in the fluid.</p><p>This thesis introduces a novel pumping concept, combining features from both displacement and radial-flow pumps. A first prototype, the Vivicor^TM pump, has been designed, fabricated and evaluated In Vitro, the results reported in this thesis.</p><p>The In Vitro evaluation of the Vivicor^TM pump provides evidence of a pump with mechanical self-regulation based on pump pre-load level, much like a displacement pump. The Vivicor^TM pump also displays pulsating outflow in combination with an inflow both during pump systole and diastole. The latter provides potential advantages over traditional displacement pumps as smaller cannulae or catheters can be used, facilitating miniaturization. Continuos filling throughout the pumping cycle also require less pressure to be exerted on the fluid, compared to displacement pumps, limiting the risk of mechanical damage to the pumped fluid. The In Vitro evaluation has also provided further insights on necessary design modifications in the second-generation Vivicor^TM prototype, currently planned. The Vivicor^TMpumping technology is highly interesting for further development and evaluation for use in ventricular assist applications.</p>

<p>Volume rendering techniques can be powerful tools when visualizing medical data sets. The characteristics of being able to capture 3-D internal structures make the technique attractive. Scanning equipment is producing medical images, with rapidly increasing resolution, resulting in heavily increased size of the data set. Despite the great amount of processing power CPUs deliver, the required precision in image quality can be hard to obtain in real-time rendering. Therefore, it is highly desirable to optimize the rendering process.</p><p>Modern GPUs possess much more computational power and is available for general purpose programming through high level shading languages. Efficient representations of the data are crucial due to the limited memory provided by the GPU. This thesis describes the theoretical background and the implementation of an approach presented by Patric Ljung, Claes Lundström and Anders Ynnerman at Linköping University. The main objective is to implement a fully working multi-resolution framework with two separate pipelines for pre-processing and real-time rendering, which uses the GPU to visualize large medical data sets.</p>

<p>I hälso- och sjukvården i Sverige används ett flertal medicintekniska apparater och IT-system. Ofta läser man av en skärm på den medicintekniska apparaten och noterar informationen på papper för att sedan manuellt mata in dessa uppgifter i IT-systemen. Detta manuella mellanled finns det önskemål och förhoppningar om att slippa. Man vill kunna överföra information automatiskt mellan den medicintekniska apparaten och IT-systemet, med andra ord vill man integrera dem. För att åstadkomma detta måste ett antal grund-läggande förutsättningar uppfyllas. Bland annat ställs vissa krav på tekniken hos den medicintekniska apparaten, kommunikationskanalen och IT-systemet. Dessutom är det nödvändigt att uppfylla gällande lagar och regler. Utöver detta finns det faktorer som kan underlätta, till exempel användandet av erkända standarder för kommunikationen. Syftet med detta examensarbete har varit att belysa och utreda dessa bakomliggande faktorer för att få integration av nyss beskrivet slag att fungera. Arbetet är en bakgrundsstudie på detta område.</p>

<p>First-year students at Linköping University have developed a prototype that graphically visualizes a medical record in a new way. The customer of that project was the Department of Biomedical Engineering at Linköping University. They now want a usability evaluation to be performed of the prototype. The prototype is to be used by employees in the public health care and is supposed to be used on a small portable unit with a multi-touch interface. For this reason the prototype will be used as a complement to existing systems when the users work near the patients. Since the prototype is still in the design phase it is important that the continuing development is carried out in close collaboration with the users.</p><p>The purpose of this thesis was to point out which usability problems the prototype violates and which needs it must satisfy. The purpose was also to examine how the users interact with an iPod touch and what they consider of using an iPod touch. Usability is created when human interacts with a product to achieve specified goals, where the product is easy to learn, effective to use, easy to remember, has few errors and is satisfactory to use. By early and continuously involving the users in its development a product is able to reach a high level of usability. In this thesis a number of well known usability methods were used, e.g. interviews, heuristic evaluation and thinking aloud protocol. All these methods are described thoroughly in this report among with a review of how they were implemented. Finally, these methods are being discussed together with the obtained results.</p><p>During the interviews with the users a number of usability problems in the prototype were discovered together with the users’ needs which it must satisfy. It was also discovered that most of the users thought positive of working with an iPod touch. In the continuing development of the prototype these usability problems should be fixed in order to satisfy the users’ needs.</p> / <p>Förstaårsstudenter vid Linköpings Universitet har utvecklat en prototyp som på ett nytt sätt visualiserar en patientjournal grafiskt. Beställare av projektet var Institutionen för medicinsk teknik vid Linköpings Universitet som nu vill att en användbarhetsutvärdering genomförs av prototypen. Prototypen riktar sig till anställda inom sjukvården och ska användas på en liten handhållen enhet med pekskärm. Av denna anledning ska den vara ett komplement till befintliga system när användarna arbetar nära patienterna. Då den ännu befinner sig tidigt i utvecklingsstadiet är det nödvändigt att fortsatt utveckling sker i nära kontakt med användarna.</p><p>Detta examensarbete syftade till att peka på vilka användbarhetsprinciper prototypen bryter mot, vilka behov den måste tillgodose, att undersöka hur användarna interagerar med en Ipod touch och vad de anser om att arbeta med en sådan enhet. Användbarhet uppstår när människan interagerar med en produkt för att lösa givna uppgifter, där produkten är lätt att lära, effektiv att använda, har få fel, är subjektivt tilltalande och där det är lätt att komma ihåg hur den används. Genom att tidigt och kontinuerligt involvera användarna i utvecklingsarbetet uppnås god användbarhet. I detta arbete tillämpades ett flertal kända användbarhetsmetoder, bl.a. intervjuer, heuristisk utvärdering och tänka högt. Alla metoder finns beskrivna teoretiskt i rapporten tillsammans med en redogörelse för hur de tillämpades. Slutligen följer en diskussion kring dem och det resultat som erhölls.</p><p>Under intervjuerna med användarna framkom flera användbarhetsproblem i prototypen samt de behov den måste tillgodose. Arbetet kom även fram till att användarna över lag ställer sig positiva till att arbeta med en Ipod touch. I den fortsatta vidareutvecklingen av prototypen bör dessa användbarhetsproblem åtgärdas för att prototypen ska tillgodose användarnas behov.</p>

<p>Phase-contrast magnetic resonance imaging (PC-MRI) is a powerful tool for measuring blood flow and has a wide range of cardiovascular applications. Simulation of PC-MRI from numerical flow data would be useful for addressing the data quality of PC-MRI measurements and to study and understand different artifacts. It would also make it possible to optimize imaging parameters prior to the PC-MRI measurements and to evaluate different methods for measuring wall shear stress.</p><p>Based on previous studies a PC-MRI simulation tool was developed. An Eulerian-Lagrangian approach was used to solve the problem. Computational fluid dynamics (CFD) data calculated on a fix structured mesh (Eulerian point of view) were used as input. From the CFD data spin particle trajectories were computed. The magnetization of the spin particle is then evaluated as the particle travels along its trajectory (Lagrangian point of view).</p><p>The simulated PC-MRI data were evaluated by comparison with PC-MRI measurements on an in vitro phantom. Results indicate that the PC-MRI simulation tool functions well. However, further development is required to include some of the artifacts. Decreasing the computation time will make more accurate and powerful simulations possible. Several suggestions for improvements are presented in this report.</p>

Deep brain stimulation (DBS) is a surgical treatment technique, which involves application of electrical pulses via electrodes inserted into the brain. Neurons, typically located in the basal ganglia network, are stimulated by the electrical field. DBS is currently widely used for symptomatically treating Parkinson’s disease patients and could potentially be used for a number of neurological diseases. In this study, computational modeling was used to simulate the electrical activity of neurons being affected by the electrical field, to gain better understanding of the mechanisms of DBS. The spatial and temporal distribution of the electrical field was coupled to a cable model representing a human myelinated axon. A passing fiber with ends infinitely far away was simulated. Results show that excitation threshold is highly dependent on the diameter of the fiber and the influence (threshold-distance and threshold-diameter relations) can be controlled to some extent, using charge-balanced biphasic pulses.

Volume rendering techniques can be powerful tools when visualizing medical data sets. The characteristics of being able to capture 3-D internal structures make the technique attractive. Scanning equipment is producing medical images, with rapidly increasing resolution, resulting in heavily increased size of the data set. Despite the great amount of processing power CPUs deliver, the required precision in image quality can be hard to obtain in real-time rendering. Therefore, it is highly desirable to optimize the rendering process. Modern GPUs possess much more computational power and is available for general purpose programming through high level shading languages. Efficient representations of the data are crucial due to the limited memory provided by the GPU. This thesis describes the theoretical background and the implementation of an approach presented by Patric Ljung, Claes Lundström and Anders Ynnerman at Linköping University. The main objective is to implement a fully working multi-resolution framework with two separate pipelines for pre-processing and real-time rendering, which uses the GPU to visualize large medical data sets.

First-year students at Linköping University have developed a prototype that graphically visualizes a medical record in a new way. The customer of that project was the Department of Biomedical Engineering at Linköping University. They now want a usability evaluation to be performed of the prototype. The prototype is to be used by employees in the public health care and is supposed to be used on a small portable unit with a multi-touch interface. For this reason the prototype will be used as a complement to existing systems when the users work near the patients. Since the prototype is still in the design phase it is important that the continuing development is carried out in close collaboration with the users. The purpose of this thesis was to point out which usability problems the prototype violates and which needs it must satisfy. The purpose was also to examine how the users interact with an iPod touch and what they consider of using an iPod touch. Usability is created when human interacts with a product to achieve specified goals, where the product is easy to learn, effective to use, easy to remember, has few errors and is satisfactory to use. By early and continuously involving the users in its development a product is able to reach a high level of usability. In this thesis a number of well known usability methods were used, e.g. interviews, heuristic evaluation and thinking aloud protocol. All these methods are described thoroughly in this report among with a review of how they were implemented. Finally, these methods are being discussed together with the obtained results. During the interviews with the users a number of usability problems in the prototype were discovered together with the users’ needs which it must satisfy. It was also discovered that most of the users thought positive of working with an iPod touch. In the continuing development of the prototype these usability problems should be fixed in order to satisfy the users’ needs. / Förstaårsstudenter vid Linköpings Universitet har utvecklat en prototyp som på ett nytt sätt visualiserar en patientjournal grafiskt. Beställare av projektet var Institutionen för medicinsk teknik vid Linköpings Universitet som nu vill att en användbarhetsutvärdering genomförs av prototypen. Prototypen riktar sig till anställda inom sjukvården och ska användas på en liten handhållen enhet med pekskärm. Av denna anledning ska den vara ett komplement till befintliga system när användarna arbetar nära patienterna. Då den ännu befinner sig tidigt i utvecklingsstadiet är det nödvändigt att fortsatt utveckling sker i nära kontakt med användarna. Detta examensarbete syftade till att peka på vilka användbarhetsprinciper prototypen bryter mot, vilka behov den måste tillgodose, att undersöka hur användarna interagerar med en Ipod touch och vad de anser om att arbeta med en sådan enhet. Användbarhet uppstår när människan interagerar med en produkt för att lösa givna uppgifter, där produkten är lätt att lära, effektiv att använda, har få fel, är subjektivt tilltalande och där det är lätt att komma ihåg hur den används. Genom att tidigt och kontinuerligt involvera användarna i utvecklingsarbetet uppnås god användbarhet. I detta arbete tillämpades ett flertal kända användbarhetsmetoder, bl.a. intervjuer, heuristisk utvärdering och tänka högt. Alla metoder finns beskrivna teoretiskt i rapporten tillsammans med en redogörelse för hur de tillämpades. Slutligen följer en diskussion kring dem och det resultat som erhölls. Under intervjuerna med användarna framkom flera användbarhetsproblem i prototypen samt de behov den måste tillgodose. Arbetet kom även fram till att användarna över lag ställer sig positiva till att arbeta med en Ipod touch. I den fortsatta vidareutvecklingen av prototypen bör dessa användbarhetsproblem åtgärdas för att prototypen ska tillgodose användarnas behov.