Ovidiu Cristian Andronesi1, Borjan A.
Gagoski2, Elfar Adalsteinsson2, Gregory A. Sorensen1
1Martinos Center for
Biomedical Imaging, Radiology Department, Massachusetts General Hospital,
Harvard Medical School, Charlestown, MA, United States; 2Electrical
Engineering & Computer Science, Massachusetts Institute of Technology,
Cambridge, MA, United States
Volumetric MR spectroscopic imaging (MRSI) with improved localization and rapid acquisition was developed for 3T clinical applications. Gradient modulated constant adiabaticity pulses with lower power requirements and shorter durations than typical hyperbolic secant pulses minimize artifacts such as chemical shift displacement error, non-uniform excitation, and lipid contamination. Spiral readout trajectories simultaneously acquire the frequency dimension and two of the spatial dimensions in order to speed up data collection. Four times shorter scan times or 60% smaller voxels in half time compared to conventional phase encoded were acquired on brain tumor patients, with a correspondingly lower but still clinically adequate SNR.