Reduced lipid contamination in in vivo 1H MRSI using time-domain fitting and neural network classification

A comparison of coil combination strategies in 3D multi‐channel MRSI reconstruction for patients with brain tumors

“…Lipid contamination from signals outside the prescribed voxel resulted in suboptimal combination for both the WSVD and FPphasing methods. Although previous studies have proposed a number of methods for reducing unwanted lipid by post‐processing approaches such as time‐domain fitting, data extrapolation or using the sensitivity information of the 8‐channel phased array coil and SENSE to unalias the lipid resonances and non‐iterative time‐domain fitting with the Lanczos‐based version of the HSVD method was employed to reduce the outer volume lipid signals, the WSVD algorithm could not combine channels robustly when the unwanted lipid signal was at a level comparable in magnitude to the true metabolite signals. Although Rodgers et al recently suggested that this could be avoided by either reducing the acquisition bandwidth so the contaminating signals are not recorded or zeroing the signal for chemical shifts around the contaminated signal before applying the WSVD combination method, this is not a practical solution for brain tumors, as the presence of high lipid can provide evidence for apoptosis or necrosis and it is important to be able to detect these peaks within the tumor.…”

Fast Removal of Residual Water in Proton Spectra

“…A. den Hollander, Center for NMR Research and Development, University of Alabama at Birmingham (see Acknowledgments). The measurements were performed on a 1.5-T ACS/S15 Philips Gyroscan, using a protocol developed by Philips Medical Systems (23).…”

Unaliasing lipid contamination for MR spectroscopic imaging of gliomas at 3T using sensitivity encoding (SENSE)

“…Previous studies have suggested a number of methods for suppressing or reducing unwanted lipid during data acquisition, including the use of inversion recovery sequences (5), very selective suppression (VSS) pulses (6), variable‐density spiral imaging (7), echo‐planar spectroscopic imaging (EPSI) (8), and spectral spatial pulses (9). Postprocessing approaches have also been proposed to remove lipid using time domain fitting (10) or data extrapolation (11).…”