Conventional MR structural and metabolic imaging is acquired over periods of minutes to improve signal-to-noise ratio. In the case of hyperpolarization this is not possible since the magnetization decays to thermal equilibrium on a time scale of seconds. This calls for development of novel acquisition methods.
The signal of a hyperpolarized sample is a precious resource that is rapidly and irreversibly exhausted. New acquisition schemes are therefore necessary for hyperpolarized spin systems to reach their full potential. Our aim is to develop quantitative multi-dimensional acquisition methods for hyperpolarized MR in vivo and in vitro. Our work includes fast chemical-shift imaging that can map metabolic rates in vivo, and imaging of hyperpolarized substrates such as water to measure flow and perfusion, for example.
The challenges are met using novel gradient and radiofrequency modulation schemes, inhomogeneity compensation and tailored coil designs combined with spectral-spatial undersampling, parallel acquisition and non-linear analysis.
Figure: Hyperpolarized Parallel MRI project overview; from substrate hyperpolarization to imaging biomarker. A main focus for our imaging research is multi-channel data acquisition and reconstruction explored by Rie Beck Olin, Juan Diego Sanchez and co-workers.