Imaging and coils

Hyperpolarized Magnetic Resonance has a huge potential in in vivo and in vitro applications but we need to overcome significant challenges in signal and signal acquisition.

Conventionally, signals are accumulated by repetitions over periods of minutes to days to improve signal-to-noise ratio. In the case of hyperpolarization this is not possible since the signal decays to thermal equilibrium on the time scale of seconds to minutes.

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.

The challenges will be 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.

The nature of hyperpolarization allows high acceleration of the data acquisition by parallel imaging with no or little penalty. However, the small size of the array elements and the low detection frequency of e.g. 13C and 15N, implies that noise is dominated by the coil and receiver. Cryogenic RF coils is a means to overcome this problem, but combining 1H/13C volume coils for anatomical imaging and excitation with cryogenic array receive coils for 13C poses tremendous challenge. We believe that high density cryogenic coils could have tremendous advantages in hyperpolarized MR.

http://www.hypermag.dtu.dk/Research/Imaging-and-coils
18 NOVEMBER 2017