Abstract BACKGROUND Comparative studies of dynamic susceptibility contrast (DSC) based measurement of cerebral blood volume (CBV) or cerebral blood flow (CBF) and arterial spin labelling (ASL) based measurement of CBF have previously shown good correlation of these parameters in human glioma. However, these studies were mostly done before inclusion of the mutation status of the isocitrate dehydrogenase (IDH) encoding gene in brain tumour classification. In light of the call for gadolinium-free imaging, here we investigate the effect of IDH-mutation status on the correlation between ASL and DSC-based perfusion measurements in non-enhancing glioma. MATERIAL AND METHODS Twenty-two patients with non-enhancing glioma and confirmed IDH-mutation status (next generation sequencing, 6 IDH-wildtype and 16 IDH-mutated) underwent 3T MRI scanning (GE, Milwaukee, WI, USA). Image acquisition included a 3D spiral pseudocontinuous ASL with time-encoded labelling (7 effective label delays from 0.8 to 2 s, reconstruction matrix 128x128x42, resolution 1.9x1.9x3.5 mm3), and 2D DSC imaging (122 TRs, TR/TE 1500m/18.6ms, 15 slices, voxel size: 1.88x1.88x4 mm3) in which a bolus of 7.5ml of gadolinium-based contrast agent (Gadovist, Bayer, Leverkussen, GE) was injected. A pre-load bolus of equal size was given 5 minutes prior to DSC imaging. DSC and ASL images were motion corrected and linearly registered to high resolution FLAIR images (FSL, version 5.0.9, Oxford, UK). DSC-relative CBV (rCBV), DSC-relative CBF (rCBF), and ASL-CBF maps were calculated via previously described methods. The glioma region of interest (ROI) was determined via manual segmentation on the FLAIR images. Voxel-wise Pearson’s linear correlation coefficients (ρ) within this ROI were calculated between ASL-CBF and DSC-rCBV, and between ASL-CBF and DSC-rCBF. RESULTS Normalised histograms indicate that IDH-wt glioma has higher values for ASL-CBF, DSC-rCBV, and DSC-rCBF than IDH-mutated glioma. IDH-wildtype glioma has a significantly lower ρ ASL-CBF vs DSC-rCBV and ρ ASL-CBF vs DSC-rCBF than IDH-mutated glioma (two-sample t-tests p < 0.05). CONCLUSION IDH-mutation status of non-enhancing glioma potentially affects the correlation between ASL-CBF and DSC-rCBF/rCBV and should be taken into account when moving towards ASL-only imaging. The decreased correlation between ASL and DSC-based vascular parameters in IDH-wt gliomas may be due to more aggressive vasculature in subtypes of IDH-wt tumours. Future work includes expansion of the current patient cohort (part of the ongoing iGENE study).