Methods for assessment of body composition allow studies of the complex relationships between body composition and the wellbeing of humans. The amount and distribution of adipose tissue is of great importance in these studies. This thesis describes, proposes, and evaluates new methods for assessment of body composition (amount and distribution of adipose tissue) using magnetic [...]
Manifolds in Image Science and Visualization
A Riemannian manifold is a mathematical concept that generalizes curved surfaces to higher dimensions, giving a precise meaning to concepts like angle, length, area, volume and curvature. A glimpse of the consequences of a non-flat geometry is given on the sphere, where the shortest path between two points – a geodesic – is along a [...]
Segmentation and Analysis of Volume Images, with Applications
Digital image analysis is the field of extracting relevant information from digital images. Recent developments in imaging techniques have made 3-dimensional volume images more common. This has created a need to extend existing 2D image analysis tools to handle images of higher dimensions. Such extensions are usually not straightforward. In many cases, the theoretical and [...]
Estimation of Turbulence using Magnetic Resonance Imaging
Turbulence is described by its main characteristics that are irregularity in time and space In hydromechanics, turbulence is referred to as chaotic movement superimposed on the flow of a fluid In the human body, turbulence typically arises in flows through heart valve prostheses and vascular or valvular stenoses. This thesis exploits a magnetic resonance imaging [...]
Phase Contrast MRI Measurements
Title: Simulation of Phase Contrast MRI Measurements from Numerical Flow Data 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 [...]
Nonlinear phonocardiographic Signal Processing
The stethoscope is a recognized icon for the medical profession, and for a long time, physicians have relied on auscultation for detection and characterization of cardiac disease. New advances in cardiac imaging have however changed this picture. Echocardiography and magnetic resonance imaging (MRI) have become so dominating in cardiac assessment that the main use of [...]