MR Pulse Sequence Development for Localized Dynamic Spectroscopy with 7T

Phosphorus spectroscopy using a semi-LASER sequence (Localization by Adiabatic Selective Refocusing) at 7T allows dynamic analysis of metabolism in exercising human muscles with a high time resolution e.g. (TR=6s), good specificity and a satisfying signal to noise ratio even in small volumes.
To investigate the effect of exercise to different muscles groups with a single voxel spectroscopy technique, separate measurements have to be acquired. This means that the subject has to repeat the exercise for every acquired volume of interest (VOI), which is time consuming and potentially inflicts a physiologic influence of the preceding exercise on the second measurement.
In this thesis the idea of multiple voxel acquisition is picked up and implemented with the semi-LASER acquisition scheme using the pulse programming environment of Siemens, to allow an interleaved measurement of two independent volumes within one repetition.
The user interface was modified to enable the selection of multiple independent VOIs, and phantom measurements were performed on the 7T Siemens MAGNETOM scanner at the Center for Medical Physics and Biomedical Engineering at Medical University Vienna. To evaluate the performance and to illustrate mutual influences between the volumes during multi volume acquisition, results of both single and multi voxel spectroscopy measurements were compared.
Furthermore in vivo measurements were performed to practically test the functionality and usability of the sequence. It offers the opportunity to acquire more information within the same time, i.e. from different regions, and therefore can help to improve the interpretation of dynamic MRS data in metabolic research.