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Magnetic Resonance Imaging
Up one levelThe following CMIV projects conducts research related to Magnetic Resonance Imaging.
New Clinical Quality Level for Medical Image Volumes
Image processing of medical image volumes (3D/4D data) requires a completely new approach compared to standard images (2D). Research on methods for high speed processing as well as for high image quality output is required. In a research project within the VINST programme a novel approach for solving the speed challenge was developed. Building on this “pre-study” project, this new project covers the remaining research for reaching a new clinical quality output level, while maintaining the speed. The goal is to have the research results from both projects verified in a prototype. The project is a cooperation between the company ContextVision AB and its research partner Center for Medical Image and Visualization (CMIV) at Linköping University.
Patient specific simulation of RF-treatment of liver tumors
The liver is the most common target for metastases from cancers in the abdominal organs. If possible, the liver tumors are removed by surgical resection. This,however, is often not possible due to a poor general condition of the patient or the liver. In recent years, radio frequency ablation (RFA) has become an important adjunct to modern treatment. RFA uses high-frequency electrical current to destroy tissue cells by heating them. A special needle-like electrode is inserted into the tumor and the RF current heats the surrounding tissue in order to destroy the tumor. The aim of this proposal is to develop a patient specific simulator for RFA of liver tumors. The purpose of the simulator is to simulate the thermal effect of the intervention in order to optimize the treatment and to avoid thermal damage on healthy tissue and sensitive structures such as small blood vessels and the bile ducts. Such a simulator would be useful in increasing the efficacy and safety of RFA. The project involves three major steps: Image acquisition and processing, Bio-heat modelling and, finally, evaluation. The main scientific challenges are: Development of methods for segmentation of relevant anatomical structures from MRI data; development of a heat transfer model for the liver that takes into account the cooling effect from the blood vessels; integration of the heat transfer model and the anatomic model into a patient specific RFA simulator.
Perceptual clarity influenced by semantic context and lexical access speed
Giving people an opportunity to hear an unintelligible noise-vocoded (NV) sentence after they know its identity produces a pop-out effect, i.e. a clearer percept of the NV sentence. Moreover, the percept of sentences is also clearer for semantically high-coherent sentences (e.g. “his new clothes were from France”) compared to semantically low-coherent sentences (e.g. “his great streets were from Smith”). Pop-out appears to occur when the auditory system is able to match input with top-down predictions that can be used to perceptually organize that input. This pop-out effect can be measured using a magnitude-estimation procedure. Previous behavioral study has shown that the pop-out effect depends on lexical access speed. Participants with fast lexical access (i.e. less than 200 ms) were more helped by the prior knowledge driven by the visual matching cues when intelligibility was low compared to participants with slow lexical access (i.e. more than 200 ms). In the present study, we will investigate the neural correlates of the pop-out effect produced by prior knowledge compared to that produced by semantic coherence for normal-hearing listeners. We will also explore if participants with better linguistic skills or better cognitive abilities experience a greater pop-out effect and if this could be related to a particular location
Postmortem imaging of myocardial infarction in correlation to autopsy.
The project aims on implementing MR imaging as a postmortem non-invasive investigation method for human corpses and on its validation on myocardial infarction cases compared to the cardiac autopsy findings. Furthermore, the MR scanning technique will be adapted to postmortem conditions that differ to some extent from the vital scanning conditions. This is especially true for the body core temperature and the missing of an ongoing circulation. The project is performed in a close collaboration of the CMIV and the Institute of Forensic Medicine in Linköping.
Reconstruction, quantification and analysis of whole body fat/water separated MRI
We will develop MRI-based methods to image and quantify the fat and water content in the body. Automatic and semi-automatic registration and segmentation methods will be developed to enable automatic quantification of specific tissue volumes such as visceral adipose tissue, subcutaneous tissue and muscle tissue volume. Within the project new visualization techniques are developed enabling combined visualization of segmented multi parametric MRI image volumes. The developed methods are validated in clinical research studies. Currently within one project investigating the effects of moderate alcohol consumption, within the non-invasive liver biopsy (NILB)-study as technique for correction of dynamic contrast enhanced (DCE) MRI, and one project where the effects of rehabilitation on patients suffering on chronic whiplash injuries is investigated. Another application area of the developed techniques is imaging of brown adipose tissue.
Reduction of Motion Artifacts in MRI
Cardiac Magnetic Resonance Imaging (MRI) is known to be degraded by respiratory motion during the scan. Previous methods to cope with these problems either impose a short scan time limit, prolong the scan or do not reduce the artefacts sufficiently. For time-resolved 3D phase contrast measurements of the cardiac flow and wall motion, the imaging time is already long, and image quality is of great importance. This projects aims to construct a reconstruction algorithm that is able to reduce the artefacts caused by respiration without prolonging the scan. This might be done by using a generalized reconstruction transform combined with an iterative optimization of an image quality metric.
SIMILAR - The European Taskforce Creating Human-Machine Interfaces Similar to Human-Human Communication - WP10 Medical Applications
* SIMILAR will create an integrated task force on multimodal interfaces that respond efficiently to speech, gestures, vision, haptics and direct brain connections by merging into a single research group excellent European laboratories in Human-Computer Interaction (HCI) and Signal Processing. * SIMILAR will develop a common theoretical framework for fusion and fission of multimodal information using the most advanced Signal Processing tools constrained by Human Computer Interaction rules. * SIMILAR will develop a network of usability test facilities and establish an assessment methodology. * SIMILAR will develop a common distributed software platform available for researchers and the public at large through www.openinterface.org. * SIMILAR will establish a scientific foundation which will manage an International Journal, Special Sessions in existing conferences, organise summer schools, interact with key European industrial partners and promote new research activities at the European level. * SIMILAR will address a series of great challenges in the field of edutainment, interfaces for disabled people and interfaces for medical applications. Natural immersive interfaces for education purposes and interfaces for environments where the user is unable to use his hands and a keyboard (like Surgical Operation Rooms, or cars) will be dealt with a stronger focus.
Structural and functional pathology in major depression: Effects of Electroconvulsive Treatment
Affective disorders are associated with structural as well as functional pathology of central stress and reward circuitry. In major depression, reduced hippocampal volumes have been reported to correlate with duration of untreated depression, and have been proposed to play a role in disrupted feedback inhibition of the hippocampal-hypothalamic-pituitary-adrenal (HHPA) axis. At a functional level, depressed subjects show an attentional bias to negative emotional stimuli and hyperactivity of brain structures that process these stimuli, such as e.g. the amygdala complex. This is paralleled by a hyporeactivity of brain circuitry that mediates motivation for appetitive behaviors, such as e.g. the Nc. Accumbens (NAcc). The relationship of these pathologies to each other, as well as to clinical state is, however, not well understood. Here, we will carry out a longitudinal study in which we will obtain serial volumetric / structural MR, fMRI and resting state connectivity measures, together with systematic clinical assessment, in a population of severely depressed patients who will receive electroconvulsive therapy (ECT).
Three-Dimensional Assessment of Cardiovascular Blood Flow
Blood flow dictates the form and function of the heart and blood vessels. Despite this, assessment of the cardiovascular system is predominantly based on anatomical descriptions rather than flow. Turbulent blood flow dominates the flow dynamics near clinically relevant regions such as valvular and vascular stenoses and prosthetic heart valves, but has been nearly overlooked in medical imaging. This incongruity is due mainly to inadequacies in imaging tools leading to a lack of insight into this topic. This project aims to create new tools and obtain new insights addressing persistent gaps in our understanding of complex cardiovascular macroflow by in-vivo assessment of laminar and turbulent blood flow in health and disease. Utilizing an innovative approach to phase-contrast magnetic resonance imaging combined with novel post-processing methods based on constitutive equations from fluid mechanics, we anticipate providing new methods for the assessment of stenoses and prosthetic heart valves. By studying patients with specific cardiovascular diseases, we expect to obtain new insights into the design of prosthetic heart valves, and the unique effects of different surgical approaches to valve replacement and to valvular and ventricular reconstruction.
Dissertation by Daniel Forsberg
