MRS water resonance frequency in childhood brain tumours: a novel potential biomarker of temperature and tumour environment.
Bottom Line: Mean PRF values were significantly larger for medulloblastoma compared with glioma, with a difference in the means of 0.0147 ppm (p < 0.05), while the mean PRF for glioma was significantly lower than for the healthy cohort, with a difference in the means of 0.0061 ppm (p < 0.05).Measurement of these effects could also be used as a supplementary biomarker, and further investigation is required.This study has shown that the water PRF value has the potential to be used for characterizing childhood brain tumours, which has not been reported previously.
Affiliation: School of Cancer Sciences, University of Birmingham, Birmingham, West Midlands, UK; Children's Hospital NHS Foundation Trust, Birmingham, West Midlands, UK.Show MeSH
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Mentions: All data were taken from studies using a 1.5 T scanner (Siemens Symphony Magnetom, NUM4). Patients were scanned as part of an MRS multicentre study, unoptimized for MR thermometry. The protocol included T1- and T2-weighted images of the brain and MRS and T1-weighted images of the head and spine after administration of contrast agent. MR spectra were acquired using a water suppressed chemical-shift-selective point resolved single voxel spectroscopy (PRESS) sequence (TE = 30 ms, TR = 1500 ms) with an acquisition bandwidth per point of 1.024 Hz. Cubic voxels with 2 cm or 1.5 cm length were used and 128 or 256 repetitions were acquired, respectively. Water reference spectra with eight repetitions were acquired for eddy current correction and as an internal reference for quantifying metabolite concentrations. The conventional images were used to delineate the margins of the primary tumour and enable the placement of the MRS voxel within the solid-appearing component of the tumour (Fig. 1). The risk of lipid contamination of the MRS signal from scalp or other fatty tissue was minimized by avoiding close proximity to these areas during positioning of the voxel.
Affiliation: School of Cancer Sciences, University of Birmingham, Birmingham, West Midlands, UK; Children's Hospital NHS Foundation Trust, Birmingham, West Midlands, UK.