JultikaUniversity of Oulu repository

Abstract

Magic angle artifacts can reduce the diagnostic quality of images in MRI of collagen rich tissues. The highly ordered structure of these tissues causes anisotropic T2 relaxation and the position of tissue in relation to the main magnetic field can considerably affect image intensity.

Researchers have not always agreed with each other regarding the importance of the magic angle effect in clinical studies. Explaining the phenomenon at the molecular level has turned out to be difficult, but significant progress has been made during the last few decades as research on this discipline has grown and new technological innovations have been developed. At first, the magic angle effect was considered mainly harmful, but nowadays it can be used to study the structures of collagen rich tissues, such as fiber orientation in cartilage zones. However, the magic angle effect may be the reason to prefer T1, adiabatic T1rho and other quantitative MRI parameters in imaging of collagenous tissues.

This BSc thesis introduces the basic principles of magnetic resonance imaging and biophysics related to the magic angle effect. Methods for reducing magic angle artifacts, the development of the current understanding and studies with different collagenous tissues are reviewed, as well as some devices designed to study the magic angle effect.