High-field magnetic resonance in the areas: magnetic resonance spectroscopy (MRS), functional magnetic resonance imaging (fMRI) with the BOLD contrast, diffusion-weighted imaging,perfusion-weighted imaging, high-resolution magnetic resonance imaging (HR-MRI), imaging with organ specific contrast-enhanced MRI

• Applicant: Professor Dr. Roland Felix
• Subject Area: Nuclear Medicine, Radiotherapy, Radiobiology
• Term: from 2001 to 2004
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 5320056

An increase in field strength from 1.5 T to 3 T leads to an increase in net magnetization. This results in an increased signal to noise ratio (SNR). As an approximation, SNR increases linearly with field strength. In addition, chemical shift is more prominent; it increases proportionally with field strength if measured in absolute terms [Hz]. This is advantageous in magnetic resonance spectroscopy (MRS), and in fact, this technique markedly profits from an increase in field strength, resulting in a much better resolution of the peak (Boesch 1996). Suspectibility artefacts are more pronounced at higher field strength. This effect may be disadvantageous to imaging, but BOLD imaging readily profits from this effect. In recent times, high-field MRI has mostly been used for MRS and BOLD-contrast-based fMRI. Another effect of increased field strength is shorter T1 time. In T1-weighted images of the head, this results in a decreased contrast between grey and white matter, which makes the implementation of special sequences (inversion recovery) advantageous. Better suppression of background tissue during time-of-flight angiographies can be expected, which ends in a higher image quality of these investigations.

• DFG Programme: Research Grants
• Major Instrumentation: Kernspintomograph 3T
• Instrumentation Group: 3231 MR-Tomographie-Systeme
• Participating Persons: Professor Dr. Bernd Hamm; Professor Dr. Karl-Jürgen Wolf