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Background: Arterial spin-labeling (ASL) is a viable non-invasive alternative to dynamic susceptibility contrast (DSC) for measuring cerebral blood flow (CBF). While quantitative accuracy of ASL and DSC was compared in healthy volunteers and patients, a comparison to a reference standard in patients diagnosed with glioma is still missing. Purpose: To probe the quantitative agreement between perfusion measurements based on ASL and DSC in comparison to the gold standard of PET in patients with glioma. Materials and Methods: This secondary analysis included pre-surgical ASL and DSC perfusion measurements in participants diagnosed with grade 2-4 gliomas drawn from the prospective FRONTIER study (Dutch National Trial Register - NTR5354) and compared the two techniques with the gold-standard perfusion measurement 15O-H2O-PET. The quantitative comparison was performed both in normal-appearing tissue as well as in the tumor region. The mean, maximum, and voxel-wise perfusion values were with and without normalization to normal-appearing tissue. And finally, a qualitative analysis was performed on individual cases to help interpret the quantitative results. Results: Eight patients (age 40.5 ± 17.0 years, 3 women) were analyzed. ASL showed better voxel-wise agreement with PET in the normal-appearing tissue than DSC (mean relative error of 26.8% vs. 33.8%). Within the tumor, cerebral blood flow (CBF) normalized contralateral gray matter showed similar tumor maximum values in both techniques - mean relative error of 23.2% for ASL and 22.0% for DSC. However, the mean relative error on a voxel-wise basis was better for ASL (27.2%) than for DSC (35.0%). Qualitatively, ASL tended to overestimate CBF in macrovessels, and DSC tended to overestimate CBF in non-enhancing tumors with small vessel diameters. Conclusion: While neither ASL nor DSC can readily replace 15O-H2O-PET in tumor quantitative perfusion measurement, ASL CBF presents a viable non-invasive semi-quantitative alternative to DSC for glioma imaging.

Every year, 50.000 new glioma cases occur in Europe. The optimal treatment strategy is highly personalised, depending on tumour type, grade, spatial localization, and tissue infiltration level. In research settings, advanced magnetic resonance imaging (MRI) has shown great promise to inform personalised treatment decisions. However, the use of advanced MRI in clinical practice is still scarce, due to a scattered imaging research landscape, a limited representation of MRI in established consortia for glioma, and the lack of tools and expertise for advanced MRI, available in standard clinical settings. These shortcomings delay the translation of scientific breakthroughs into novel treatment strategy developments, and limit the progression of personalised medicine. Therefore, in this work, the network Glioma MR Imaging 2.0 (GliMR) is presented. GliMR aims to build a pan-European and multidisciplinary network of experts and progress beyond the state-of-the-art in glioma imaging, by accelerating the use of advanced MRI in glioma. The Action ‘Glioma MR Imaging 2.0 (GliMR)’ was granted funding by the European Cooperation in Science and Technology (COST) in June 2019. GliMR’s first grant period ran from September 2019 to April 2020, during which several networking meetings were held and projects were initiated by the different working groups, such as reviewing of the current knowledge on advanced MRI, developing a GDPR-compliant consent form, initiating relationships with European scientific organisations, and setting up several dissemination channels, including the website www.glimr.eu. The action is funded until September 2023 and is accepting new members during its entire duration.

Data acquired for clinical purposes are often unreachable for scientific research. The General Data Protection Regulation (GDPR) in the EU introduced new safeguards to ensure patient privacy, including the transparency principle that states that information about data protection should be easily accessible in a concise and clear way, using plain language.1,2,3 Patients are often unaware that they can become active participants in the scientific process by allowing the reuse of their medical data and that privacy protection rules guarantee safe data-sharing. Having these challenges in mind, the European Cooperation in Science and Technology (COST) Action ‘Glioma MR Imaging 2.0’ (GliMR; glimr.eu) has developed an animation video that can be used to inform patients. GliMR is a network of clinicians, researchers and other stakeholders, that attempts to streamline and improve the diagnosis, prognosis, follow-up, and evaluation of treatment of brain tumours using advanced MRI techniques.4 Previously, a joint-initiative from GliMR and the Open Brain Consent resulted in the development of a GDPR-compliant template consent form and associated data user agreement.5 These templates are valuable tools to inform patients and healthy volunteers about data usage and sharing related privacy regulations, and facilitate the collection of consent. Unfortunately, patients are only exposed to this information when recruited specifically for scientific studies. Therefore, GliMR released an animation video as a tool for communication towards patients, which can be used as part of the data protection strategy within hospitals and healthcare institutions across Europe.

While agreement between ASL, DSC, and PET perfusion is well established in healthy volunteers, an analogous comparison in gliomas is still missing and more challenging. We compared ASL and DSC perfusion measurements with the gold-standard of 15 O-H 2 O-PET perfusion measurements in eight patients diagnosed with gliomas. We showed the importance of normalization to the contralateral hemisphere, and identified several examples of different regional perfusion as assessed with ASL and DSC and interpreted them using the PET reference.

Arterial Spin Labelling shows great promise for perfusion measurements; however, despite numerous volunteer reproducibility studies, comparisons have not been made using a phantom to establish differences due to the acquisition hardware and pulse sequences. We present data from a multi-site study using a perfusion phantom, targeting 3T MRI systems from a single vendor running the same software version.

Purpose/Introduction In Europe, 50,000 new cases of primary glioma occur each year, and this number is expected to rise with the aging population 1 . Established international consortia are putting tremendous research efforts into a better understanding of glioma pathology and improved treatment strategies. Magnetic resonance imaging (MRI) only has a minor role in these research efforts, despite being a widely available medical imaging modality and whilst advanced MRI techniques are emerging with great potential for improved characterisation of glioma. To exploit advanced MRI to the fullest, two issues need to be solved: (1) The scattered research landscape in which advanced MRI is being developed for glioma imaging. (2) The limited presence of advanced MRI research in established consortia for clinical work and research in glioma. To solve these issues, we have recently formed Glioma MR Imaging 2.0 (GliMR), an international consortium funded by the European Cooperation in Science & Technology (COST) 2 . In the coming 4 years, GliMR will establish an international network of experts in glioma research, patient organisations, and data and MR imaging scientists that aims to progress development and application of MRI for improved decision making in diagnosis, patient monitoring, and assessment of treatment response in clinical trials and practice. Subjects and Methods GliMR starts as a network of 37 proposers spread across 22 countries world-wide (Figure 1). There are 5 working groups (WGs) (Figure 2) that will ensure we will reach the Research Coordination and Capacity Building Objectives of the network (Table 1) via the organisation of meetings, workshops, and training schools. Additionally, individual researchers and clinicians can apply for funds to go on Short Term Scientific Missions (STSMs) and gain experience by working in a different hospital/lab abroad. The network will be open to new members and participation for all those interested is highly encouraged. Results GliMR will lead to an international network operating at the forefront of glioma imaging diagnostics. It will result into recommendations and open-access software tools for advanced MRI assessment of glioma, the creation of multi-site, cross-border data sets on glioma imaging, and strengthened connections between all stakeholders in glioma diagnostics. GliMR will facilitate further understanding of glioma pathophysiology, scientific breakthroughs in novel therapies and improve personalised patient management, ultimately increasing the quality of life of patients diagnosed with glioma. Discussion/Conclusion We would like to thank all proposers and our advisors for their input to the proposal. Special thanks go to the EORTC, GLASS, INCF, PanCare Society, Gold Standard Phantoms, Medical Software Solutions, Mediri, and Quantib for endorsing GliMR.