T-2-oximetry-based cerebral venous oxygenation mapping using Fourier-transform-based velocity-selective pulse trains

Purpose To develop a T-2-oximetry method for quantitative mapping of cerebral venous oxygenation fraction (Y-v) using Fourier-transform-based velocity-selective (FT-VS) pulse trains. Methods The venous isolation preparation was achieved by using an FT-VS inversion plus a nonselective inversion (NSI) pulse to null the arterial blood signal while minimally affected capillary blood flows out into the venular vasculature during the outflow time (TO), and then applying an Fourier transform based velocity selective saturation (FT-VSS) pulse to suppress the tissue signal. A multi-echo readout was employed to obtain venous T-2 (T-2,T-v) efficiently with the last echo used to detect the residual CSF signal and correct its contamination in the fitting. Here we compared the performance of this FT-VS-based venous isolation preparations with a traditional velocity-selective saturation (VSS)-based approach (quantitative imaging of extraction of oxygen and tissue consumption [QUIXOTIC]) with different cutoff velocities for Y-v mapping on 6 healthy volunteers at 3 Tesla. Results The FT-VS-based methods yielded higher venous blood signal and temporal SNR with less CSF contamination than the velocity-selective saturation-based results. The averaged Y-v values across the whole slice measured in different experiments were close to the global Y-v measured from the individual internal jugular vein. Conclusion The feasibility of the FT-VS-based Y-v estimation was demonstrated on healthy volunteers. The obtained high venous signal as well as the mitigation of CSF contamination led to a good agreement between the T-2,T-v and Y-v measured in the proposed method with the values in the literature.

Automated summary

In this study, a T-2-oximetry method was developed for quantitative mapping of cerebral venous oxygenation fraction using FT-VS pulse trains. The results showed that the FT-VS-based methods yielded higher venous blood signal and temporal SNR with less CSF contamination compared to the traditional approach.