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Data Acquisition and Reconstruction
Up one levelThe following CMIV projects conducts research related to the Data Acquisition and Reconstruction.
1H-MRS in ALS and Unverricht-Lundborgs disease
ALS and Unverricht Lundborg myoclonic epilepsy are two neurodegenerative diseases without curing treatment. Two pts with ALS and two with U-L are investigated with 1H-MRS of the white matter over a two year period in order to analyse the character of the neurodegenerative course. NAA, Cho, myo-Ins and Lac are analysed according to the LC model. Clinical status is checked and compared. Pharmacological intervention is tried.
Absolute Quantification of Multinuclear Magnetic Resonance Spectroscopy
The major aim of this project is in collaboration with several clinics to expand the scope of medical magnetic resonance methods of water to a large number of metabolites and other functional tissue properties in order to significantly enhance the level of todays applications of clinical MR. The work covers developing novel acquisition technologies and hardware, as well as clinical applications of quantitative molecular spectroscopy and imaging. A major long-term aim is to shift MR-applications from a qualitative to a quantitative mode.
Advanced signal processing methods for high quality funtional magnetic resonance imaging
Functional Magnetic Resonance Imaging (fMRI) is a tool for noninvasively exploring the functionality of the human brain. The method has already provided many insights to the function of the brain. Since examinations can be performed on widely available clinical MR scanners and without using exogenous contrast agents, the potential use for preoperative investigations and following up neurological diseases are important goals within reach. The proposed project aims at developing analysis methods that are able to extract relevant information from the large amount of data acquired in an fMRI examination. This includes many challenging problems such as compensating for patient motion, modeling brain hemodynamics, fusion between different MR images for neurological interpretation and efficient filtering approaches to locate active brain areas. To achieve the robustness required for routine clinical use of fMRI, advanced signal and image processing procedures that solve the above issues need to be developed and evaluated.
Biofunctionalised nanoparticles - new MRI contrast agents
Research within this project is based on the discovery of unique magnetic properties of nanosized materials. Gadolinium-containing nanoparticles can be used as tracers in molecular Magnetic Resonance Imaging (mMRI) for functional assessment of human tissue. These particles are designed for MRI applications, with high potential for microscopic imaging. The main advantages are the high contrast efficacy for each particle and the capacity to provide positive contrast, i.e. signal enhancement.
Cardiovascular blood flow assessment
The primary purpose of the cardiovascular system is to drive, control and maintain blood flow to all parts of the body. Despite the primacy of flow, cardiovascular diagnostics still rely almost exclusively on tools focused on morphological assessment. Powerful techniques emphasizing blood flow assessment are needed. Phase contrast magnetic resonance imaging (PC-MRI) allows flow quantification in three dimensions and in three directions. Recently, our group has presented a generalization of the PC-MRI technique, which utilizes not only the signal phase to quantify the mean velocity of a voxel, as in conventional velocity mapping, but also the signal magnitude to quantify the distribution of the velocities within the voxel. We will exploit this feature in order to develop methods for the assessment of wall shear stress, turbulent stresses, and pressure loss in both laminar and turbulent cardiovascular blood flow. Validation of these tools will be performed in phantom studies by comparison with laser Doppler anemometry and computational fluid dynamics simulations, in addition to in-vivo studies. The techniques developed thereby will initially be used to assess patients with aortic coarctation, prosthetic aortic valve, dilated cardiomyopathy, and mitral valve insufficiency.
Cone beam CT studies of dental and skeletal radiology
Cone-beam CT using 2D detectors and 3D reconstruction algorithms has recently become commercially available for dental use and offers isotropic, high resolution. This project aims at evaluating this technique for clinical purposes in odontological radiology and studying skeletal microstructure. In particular, imaging of the temporal bone will be evaluated.
Determining Optimal non-invasive Parameters for the Prediction of Left vEntricular morphologic and functional Remodeling in Chronic Ischemic Patients (DOPPLER-CIP)
Coronary artery disease (CAD) remains the primary cause of cardiovascular morbidity and mortality in Europe. In current clinical practice, patients with chronic CAD are followed using non-invasive imaging methodologies for possible adverse morphologic remodelling and functional recovery of the myocardium before the decision for invasive examinations and treatments is taken. Technological developments have brought about several newer imaging methodologies (and associated parameters) that have shown accurate prognostic results under study conditions in selected patient populations. Each of these methodologies offers intrinsic advantages and disadvantages due to the physiologic processes it tries to assess, due to the technology it requires or due to its availability (often determined by its associated cost). However, to date, no large scale studies have made a direct comparison of the different methodologies towards predicting adverse morphologic remodelling or functional recovery of the myocardium after medical therapy. The lack of such information results in a sub-optimal use of the methodologies at hand. The aim of DOPPLER-CIP is therefore to conduct a multi-centre clinical study including about 1200 patients in order to determine the optimal prognostic parameters derived from (new) non-invasive imaging for a patient presenting with suspected chronic ischemic heart disease. The modality used to extract these parameters is of secondary importance. However, as both the accuracy and the cost related to extracting a particular parameter is modality-dependent, DOPPLER-CIP will also make a cost-effective analysis in order to determine which modality should preferentially be used to extract the clinically most relevant parameter. The study is financed by the European Union and is coordinated from Leuven, Belgium with cooperating centers in Linkoping, London, Madrid, Oslo, Pisa and Turku. Several add-on studies in Linköping will have access to this wealth of patient data for more in-depth analysis of wall motion and blood flow.
Development of functional Magnetic Resonance Imaging (fMRI) for clinical applications
Functional magnetic resonance imaging (fMRI) is a non-invasive method to study localisation of brain function. The method is based upon the increased blood flow that follows neuronal activity. Blood oxygen level dependent (BOLD) fMRI utilise the difference in magnetic properties between oxygenated and deoxygenated blood as image contrast. Research within fMRI has mainly been focused on method development and normal cognition. Today, there is a considerable interest in using fMRI as a clinical tool for presurgical mapping and studies of impaired brain function and rehabilitation. However, fMRI in clinical settings is a challenge. Patients may be affected by pain, anxiety, and cognitive impairments. These are conditions that might cause reduced task focusing, perception, and attention. Patient adapted tasks are therefore crucial for clinical fMRI.
Effect of reperfusion on infarct size and cardiac function evaluated with MRI and echocardiography - MrSTEMI
Mechanical opening of the infarct related artery (primary PCI) in patients with ST-elevation myocardial infarction (STEMI) seems to produce better results than iv thrombolysis. Our hypothesis is that primary PCI saves myocardium, that the size of myocardial damage is best quantified with contrast-enhanced MR (CEMR), that salvaged myocardium translates into better cardiac function, and that the time to opening of the artery is directly related to the size of the infarct. We will attempt to study the effect of the delay between the start of symptoms and the opening of the infarct related artery. The infarct risk area will be estimated from echocardiography performed in the cath lab during initiation of treatmentand expressed in terms of wall motion score index, WMSI. The final damage will be assessed from a comprehensive MR study with late enhancement performed at 6 weeks post PCI.
Functional MRI studies of normal and impaired language function
Language ability plays an important role when communicating with others. Before a-typical language activation can be detected in patient populations, normal language function has to be explored. In this project we intend to study the influence of performance and difficulty related language ability on cortical activation in healthy subjects and in patients with language disability.
Functioning and disability in adults after obstetric brachial plexus (OBP) injury - an fMRI study
In complicated deliveries, traction of the nerve plexus responsible for arm and hand sensibility and motor function can occur resulting in transient or permanent nerve dysfunction. This injury is referred to as brachial plexus (OBP) injury and occur in about 2-3% of all deliveries. In this project we intend to study the consequences of OBP on cortical activation in patients.
Identification of cognitive processes with fMRI and auditory stimulation in hearing impaired with and without hearing aids
Within this project, we will investigate the neural correlates of cognitive processes during speech intelligibility in noise. The data will be analysed according to the working memory framework of Ease of Language Understanding (ELU) developed by Rönnberg and colleagues. This model states that the demands on cognitive (‘explicit’) processing increase when speech comprehension is impaired by background noise, hearing loss, or altered by the type of signal processing in the hearing instrument.
Implementation of Synthetic MRI into the clinical workflow.
Synthetic MRI is the approach of rapid quantification of MRI parameters and the subsequent synthesis of a whole range of contrast images based on the quantified data. This implies that a single scan is sufficient to generate any conventional T1- or T2 weighted image. It is even possible to visualize far stronger, non-physical contrast such as tissue specific imaging. Application of Synthetic MRI might save up to a third of the patient examination time and will make MRI more reliable and quantitative. The project aims at the clinical implementation of the approach into the PACS system. The technique of rapid quantification is more or less mature but the general use of Synthetic MRI in daily clinic needs to be introduced and validated. In addition to the investigation of the quality of the resulting images the specification of the time-saving aspect will be important. Cardiac Late Enhancement is implemented first and the validation is on-going. Synthetic Brain imaging is implemented at the moment. Future directions will concern the liver.
Magnetic Resonance Imaging of the Brain in Different States of Visceral Sensitivity
This project aims to elucidate the pathophysiological mechanisms of visceral hypersensitivity in patients with Irritable Bowel Syndrome and compare the findings with those in healthy controls. Much time will be spent on method development.
Morphology Guided fMRI
As the potentials for treating neurological disorders have increased tremendously the last decades, there is also a growing need for safe, reliable and cost-effective diagnostic tools. fMRI is valuable both for an improved description of normal brain function and for assessment of patients with neurological disorders. The core theoretical idea in the project is that by including/developing tools for reconstruction of the brains cortical surface new and highly significant local spatial priors can be included in the fMRI data analysis and in this way significantly improve detection performance.
MOVIII Demonstrator Project: Bio-Feedback Using Real-Time fMRI
Despite the enormous complexity of the human mind, fMRI techniques are able to partially observe the state of a brain in action. In this paper we describe an experimental setup for real-time fMRI in a bio-feedback loop. One of the main challenges in the project is to reach a detection speed, accuracy and spatial resolution necessary to attain sufficient bandwidth of communication to close the bio-feedback loop. To this end we have banked on our previous work on real-time filtering for fMRI and system identification, which has been tailored for use in the experiment setup. In the experiments presented the system is trained to estimate where a person in the MRI scanner is looking from signals derived from the visual cortex only. We have been able to demonstrate that the user can induce an action and perform simple tasks with her mind sensed using real-time fMRI.The technique may have several clinical applications, for instance to allow paralyzed and "locked in" people to communicate with the outside world. In the meanwhile, the need for improved fMRI performance and brain state detection poses a challenge to the signal processing community. We also expect that the setup will serve as an invaluable tool for neuro science research in general.
MRI in the diagnosis of Neuroborreliosis
This project attempts to study whether MRI can contribute to the diagnosis of Borrelia infection iin the brain. A unique material of acute and chronic patients with proven or suspected neuroborreliosis will, in addition to clinical, biochemical and immunological methods for diagnosis, be examined with MRI of the brain. An extensive MRI protocol is used, including Gd-enhanced images and diffusion-weighted imaging, as well as methods for quantitative assessment of MR parameters and synthetic MRI developed at CMIV.
MS studies with proton spectroskopy, fMRI and quantitative MRI
Multiple sclerosis is studied with different MRI techniques: (I) 1H-MR-Spectroscopy - a continuation of MRS studies conducted in Linköping since the 1990's, (II) functional MRI - with particular respect to the fatigue symptom in MS, (III) Quantitative MRI (QRAP) - a new technique developed within CMIV
Neuro-imaging in Kleine Levin syndrome
Kleine Levin syndrome is a rare disease affecting young people giving periodic hypersomnia combined with hyperphagia and other psychological symptoms. Our research has demonstrated hypoperfusion in temporofrontal regions on SPECT and a short term memory dysfuntion. We have a material of 15 patients and are examining them using cerebral fMRI with a cognitive paradigm for verbal memory and concentration. Preliminary results have revealed a thalamic dysfunction when compared to healthy ctrls. We also use 1H-MRS of hippocampus in search of an organic substrate for the memory dysfunction. The study aims at finding the biological substrate of this disease.
New dimensions in ultrasound contrast imaging - Visualization of myocardial blood flow
Aims are: 1. To find new bubble excitation strategies for improved contrast/tissue ratio of the ultrasound image 2. To perform ultrasound pulse field and contrast bubble response simulations 3. To peruse corresponding in vitro experiments 4. To deliver the contrast optimized pulse sequences for implementation in echocardiographs (for clinical studies)
Inger Stern 
Ph D Dissertation, Lene Rosendahl
