Fabio Nery1, Iosif Mendichovszky2, Pim Pullens3, Ilona Dekkers4, Octavia Bane5, Andreas Pohlmann6, Anneloes de Boer7, Alexandra Ljimani8, Aghogho Odudu9, Charlotte Buchanan10, Kanishka Sharma11, Christoffer Laustsen12, Anita Harteveld7, Xavier Golay13, Ivan Pedrosa14, David Alsop15, Sean Fain16, Anna Caroli17, Pottumarthi Prasad18, Susan Francis10, Eric Sigmund19, Maria Fernández‐Seara20, and Steven Sourbron21
1Developmental Imaging and Biophysics Section, UCL Great Ormond Street Institute of Child Health, London, UK, London, United Kingdom, 2Department of Radiology, Addenbrooke’s Hospital, Cambridge University Hospitals NHS Foundation Trust, Cambridge, United Kingdom, 3Department of Radiology, Ghent University Hospital and Ghent Institute for Functional and Metabolic Imaging, Ghent University, Ghent, Belgium, 4Department of Radiology, Leiden University Medical Center, Leiden, Netherlands, 5Translational and Molecular Imaging Institute and Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, NY, United States, 6Berlin Ultrahigh Field Facility, Max Delbrueck Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany, 7Department of Radiology, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands, 8Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, 40225, Dusseldorf, Germany, 9Division of Cardiovascular Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom, 10Sir Peter Mansfield Imaging Centre, University of Nottingham, University Park, Nottingham, United Kingdom, 11Imaging Biomarkers Group, Department of Biomedical, Imaging Sciences, University of Leeds, Leeds, United Kingdom, 12Department of Clinical Medicine, MR Research Centre, Aarhus University, Aarhus, Denmark, 13Brain Repair and Rehabilitation, Institute of Neurology, University College London, London, United Kingdom, 14Department of Radiology, Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, United States, 15Department of Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States, 16Departments of Biomedical Engineering, Radiology, and Medical Physics, University of Wisconsin, Madison, WI, United States, 17Department of Biomedical Engineering, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy, 18Department of Radiology, Center for Advanced MR Research, NorthShore University Health System, Evanston, IL, United States, 19Department of Radiology, Center for Biomedical Imaging (CBI), Center for Advanced Imaging Innovation and Research (CAI2R), NYU Langone Health, New York, NY, United States, 20Department of Radiology, Clínica Universidad de Navarra, Pamplona, Spain, 21Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, United Kingdom
Synopsis
The field of renal MRI has undergone significant developments
over the last decade. However, the lack of standardisation of acquisition and
analysis methods remains an important barrier to clinical translation. We
present a consensus project initiated through the Cooperation in Science and
Technology (COST) Action PARENCHIMA whereby a group of renal MRI experts
employed a Delphi-based approach to develop technical recommendations for renal
T1 and T2 mapping, arterial spin labelling,
diffusion-weighted imaging and blood oxygenation level-dependent MRI. These
will promote standardisation of renal MRI protocols and thus facilitate
clinical translation and comparison of data across sites.
Introduction
The field of renal MRI has undergone significant
developments over the last decade and the potential of non-invasive renal MRI
biomarkers is becoming increasingly recognised by the nephrology community1. However, the lack of
standardisation in acquisition and analysis methods remains an important
barrier to the translation of renal MRI to the clinic. We report on an
initiative to generate technical recommendations to facilitate clinical
translation of renal MRI, focusing on five techniques: T1 and T2
mapping, arterial spin labelling (ASL), diffusion-weighted imaging (DWI) and
blood oxygenation level-dependent MRI (BOLD). Methods
A taskforce2 for technical recommendations
on clinical renal MRI was formed under the framework of the European
Cooperation in Science and Technology (COST) Action PARENCHIMA CA161033. A 7-stage process for
consensus generation was defined4: (1) formation of expert
panels; (2) definition of the context of use; (3) literature review; (4)
collection and comparison of MRI protocols; (5) consensus generation by an
approximate Delphi method; (6) reporting of results in vendor-neutral and
vendor-specific terms; (7) ongoing review and updating5.
Four multidisciplinary panels were formed on MRI methods where
a literature review (stage 3) and protocol comparison (stage 4) was performed
recently (renal T1/T2 mapping, ASL, DWI and BOLD). The combined panels
comprised over 50 scientists. Following an approximate Delphi process (stage
5), all panels conducted a first round of surveys, followed by an intermediate
in-person meeting to highlight and review initial areas of consensus or lack
thereof6. A second iteration with a refined
survey followed. Finally, sets of technical recommendations were written up
independently by each panel, and subsequently edited to ensure a coherent set
of results and presentation across the panels (stage 6). Results
In total, 175 consensus statements were developed providing
recommendations for renal MRI, with 36 on T1 and T2 mapping (17 respondents), 23
on BOLD (24 respondents), 57 on DWI (21 respondents) and 59 on ASL (23
respondents). Standalone manuscripts detailing these recommendations have been
published or are in press at the time of writing (Dekkers et. al.7, Bane et. al.8, Ljimani et. al.9 and Nery et. al.10). The recommendations include
aspects related to patient preparation, hardware considerations, sequence
parameters, data analysis and reporting. Areas where consensus was not found
were highlighted. A GitHub repository was created as a placeholder for future
submissions of compliant MRI protocols and released on Zenodo11.Discussion
This work demonstrates that a systematic approach to
generate consensus can be used to define technical recommendations for a wide
variety of MRI methods in a relatively short time frame (~1 year). This process
also proved effective in highlighting current areas where there is a lack of
agreement, many unresolved due to gaps in the literature which point to
important avenues for future research. We believe the approach taken can
generalise to a wider number of MRI techniques and application areas, and a
standalone manuscript (Mendichovszky et. al.5) has been published to
disseminate these methods.
Future plans include making available detailed acquisition
protocols in vendor-specific terminology to facilitate the implementation of
these methods by less experienced sites11, as well as sharing example
data obtained following these recommendations. Furthermore, we anticipate that
these recommendations will be revisited in the future and undergo iterative
updates to reflect progress in the field. A process which is currently in preparation
will be made available through the task force webpage2.Conclusion
Consensus-based technical recommendations were formulated
for renal T1 and T2 mapping, ASL, DWI and BOLD MRI. These have the potential to
lay a foundation for widespread adoption of these techniques, harmonisation of
acquisition and processing methods and facilitate clinical translation. The
systematic approach for consensus generation developed in this work may be useful
in future projects involving other MRI techniques and application areas and
indeed for future revisions of the current recommendations as the field of
renal MRI evolves and new evidence becomes available.Acknowledgements
Work carried out under the COST Action CA16103 Magnetic
Resonance Imaging Biomarkers for Chronic Kidney Disease (PARENCHIMA), funded by
COST (European Cooperation in Science and Technology). For additional
information, please visit PARENCHIMA project website: www.renalmri.org.
XG is CEO of Gold Standard Phantoms. IP participated in a
Scientific Advisory Board for Bayer Healthcare. DA is the inventor of PCASL
labeling and receives royalties through his institution from licenses to GE,
Philips, Hitachi and Siemens.
References
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