Optimizing MRSI semi-LASER for mouse brain tumor studies: evaluation of increased spatial resolution and k-space sampling strategies

MRSI-based nosological images have been previously applied to monitor therapy response in a murine model of GL261 glioblastoma using a commercially available MRSI-PRESS sequence. Due to the heterogeneous nature of glioblastomas, increasing spatial resolution could provide additional insight into changes related to therapy response. The in-house implementation of the MRSI-semi-LASER sequence, using weighted acquisition, has allowed us a 20% slice thickness reduction without losing relevant spectral quality. Moreover, different k-space sampling strategies have been evaluated showing significant SNR increase with elliptical sampling, which may allow further increase in the spatial resolution or reduction in the total experimental time.