title: Improved localisation for 2-hydroxyglutarate detection at 3T using long-TE semi-LASER.
abstract: 2-hydroxyglutarate (2-HG) has emerged as a biomarker of tumour cell IDH mutations that may enable the differential diagnosis of glioma patients. At 3 Tesla, detection of 2-HG with magnetic resonance spectroscopy is challenging because of metabolite signal overlap and a spectral pattern modulated by slice selection and chemical shift displacement. Using density matrix simulations and phantom experiments, an optimised semi-LASER scheme (TE = 110 ms) improves localisation of the 2-HG spin system considerably compared to an existing PRESS sequence. This results in a visible 2-HG peak in thein vivospectra at 1.9 ppm in the majority of IDH mutated tumours. Detected concentrations of 2-HG were similar using both sequences, although the use of semi-LASER generated narrower confidence intervals. Signal overlap with glutamate and glutamine, as measured by pairwise fitting correlation was reduced. Lactate was readily detectable across glioma patients using the method presented here (mean CLRB: (10±2)%). Together with more robust 2-HG detection, long TE semi-LASER offers the potential to investigate tumour metabolism and stratify patientsin vivoat 3T.
authors.affiliation: FMRIB Centre, Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom.
authors.forename: Adam
authors.initials: A
authors.lastname: Berrington
authors.affiliation: FMRIB Centre, Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom.
authors.forename: Natalie L
authors.initials: NL
authors.lastname: Voets
authors.affiliation: Department of Neurosurgery, John Radcliffe Hospital, Oxford University Hospitals NHS Trust, Oxford, United Kingdom.
authors.forename: Puneet
authors.initials: P
authors.lastname: Plaha
authors.affiliation: Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom.
authors.forename: Sarah J
authors.initials: SJ
authors.lastname: Larkin
authors.affiliation: Department of Chemistry, University of Oxford, Oxford, United Kingdom.
authors.forename: James
authors.initials: J
authors.lastname: Mccullagh
authors.affiliation: Department of Neurosurgery, John Radcliffe Hospital, Oxford University Hospitals NHS Trust, Oxford, United Kingdom.
authors.forename: Richard
authors.initials: R
authors.lastname: Stacey
authors.affiliation: Advanced Diagnostic Imaging, Philips Healthcare, Netherlands.
authors.forename: Muhammed
authors.initials: M
authors.lastname: Yildirim
authors.affiliation: Department of Chemistry, University of Oxford, Oxford, United Kingdom.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Schofield
authors.affiliation: FMRIB Centre, Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom.
authors.forename: Peter
authors.initials: P
authors.lastname: Jezzard
authors.affiliation: Department of Neurosurgery, John Radcliffe Hospital, Oxford University Hospitals NHS Trust, Oxford, United Kingdom.
authors.forename: Tom
authors.initials: T
authors.lastname: Cadoux-Hudson
authors.affiliation: Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom.
authors.forename: Olaf
authors.initials: O
authors.lastname: Ansorge
authors.affiliation: FMRIB Centre, Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom.
authors.forename: Uzay E
authors.initials: UE
authors.lastname: Emir
keywords: 2-HG; 3T; MRS; glioma; semi-LASER