Publikationsserver der RWTH Aachen University
Biomedizinische Anwendungen der NMR-MOUSE
Abstract
dc:descriptionThe thesis is about investigations of biological tissues by mobile NMR.One aim of the project was the investigation of anisotropic structures in tendon by a mobile MR probe in order to achieve improvements in the early diagnosis of degeneration in Achilles tendon. Secondly the MR probe was used to detect cancer in female breast. The probe used for the study is of the NMR-MOUSE type. It consists of two permanent magnets placed on an iron yoke to form the classical horse-shoe magnet geometry, by which a static inhomogeneous magnetic field is generated above the probe. A radio-frequency coil is placed in the gap between the magnets for excitation and reception of the NMR signal. The tissue sample is either directly placed on top of the probe surface, or the NMR-MOUSE is fixed to a freely rotatable holding device, by which it can be adjusted to the measurement position of interest. Within a few minutes the transverse relaxation time T2 is measured, which can be correlated to the type of tissue and its condition at the position investigated. The measurement depth can be adjusted from 0 to 5 mm, which allows the examination of not only achilles tendon but also the adjacent tissues. In tissues with an anisotropic molecular structure the transverse relaxation time T2 depends on the orientation of the sample relative to the main direction of the static magnetic field. Measurements of T2 as a function of this orientation angle exhibit the "magic angle" effect, which can be exploited for characterization of molecular order. In-vitro measurements on animal tendon prove that the angular T2 anisotropy can reproduceable be determined by a mobile probe like the NMR-MOUSE. The experimental results of both the in-vitro measurements on animal tendon as well as the in-vivo measurements of healthy human volunteers are in good agreement with to the theoretically expected properties. Early diagnosis of cancer is one of the main objectives in medicine. To improve the detection and staging of breast cancer, gadolinium-enhanced magnetic resonance imaging was being developed as an alternative approach to mammography. Using a mobile MR probe contraindications of conventional MR tomographes can be avioded. Due to the different relaxation times a discriminiation between benign and malignant breast tumores is possible. The main advantage of the NMR-MOUSE is its mobility, so that this new MR system has the potential to become a new diagnostic tool complementing the conventional and established devices.
Degree
thesis:*- Grantor dc:publisher
- Publikationsserver der RWTH Aachen University
- Year dc:date
- 2003
Author and committee
dc:creator, dc:contributor.*- Author dc:creator
-
- Schwaiger, Andrea
- Contributors dc:contributor
-
- Blümich, Bernhard
Subjects
dc:subject × 6Rights
dc:rights- Statement dc:rights
-
- info:eu-repo/semantics/openAccess
- Language dc:language
- ger