2. MRI 装置によるスペクトロスコピーの基礎的検討(MRS の現状と技術的課題)

Abstract

Technical aspects of image selected in vivo spectroscopy (ISIS) and fast rotating gradient spectroscopy (FROGS) are reported. Experiments were performed on a 1.5 T MRI system for human body by using a surface coil tuned to phosphorus-31. Phantoms filled with phosphoricacid solustions and normal ten volunteers were examined. We focused on the dependence of the signal intensity on RF transmitter power, volume selectivity, and the positional shift due to chemical shift. Results are as follows : Transmitter power to excite spins increased with conductivity and volume of phantoms. The peak hight of the spectrum of the heart of human volunteers changed depending on the transmitter power and repetition time. In ISIS, volume selectivity was good in large volume selection. While, in FROGS, it was good in thin slice selection. Positional shift due to chemical shift was not negligible in both techniques, but the distance changed depending on the strength of the gradient field used.