Sahar Nassirpour

- PhD student at Max Planck Institute for Biological Cybernetics

- Ultra High Field Department

- The purpose of my PhD thesis is to develop acquisition sequences, image reconstruction methods and quantification routines to enable whole brain metabolic imaging and quantification in the human brain by magnetic resonance spectroscopy at 9.4T.

Accelerated Multi-slice ¹H FID-MRSI in the human brain at 9.4 T

Magnetic resonance spectroscopic imaging (MRSI) is a powerful technique for mapping metabolites over the entire brain volume that can provide sensitive markers of disease or injury and therefore plays an important role both in clinical diagnostics and in biomedical research. Compared to lower field strengths, MRSI at ultra-high fields has the advantage of higher signal to noise ratio as well as increased spectral resolution. This advantage enables the quantification of more metabolites in the brain. However, to be able to benefit from these advantages at ultra-high fields, there are many challenges that should be overcome. Some of these challenges include: shortened T2 and T2* relaxation times, severe chemical shift displacement artifacts, high spatial B₁⁺ field inhomogeneity, long acquisition times, large B₀ field inhomogeneity across the entire brain volume and processing of large multi-dimensional datasets in a robust and efficient manner. The purposes of this PhD thesis is to develop acquisition sequences, image reconstruction methods and quantification routines to overcome these challenges and enable whole brain metabolic imaging and quantification in the human brain by magnetic resonance spectroscopy at 9.4T.

Using the ¹H FID MRSI sequence at 9.4T, we are able to reliably map up to 12 metabolites at a high resolution of 64x64. By using acceleration techniques and reducing the scan time, metabolite maps of the entire brain can be acquired in a reasonable scan time.