Open Science Initiative for Perfusion Imaging (OSIPI): Arterial Spin Labeling Imaging and Analysis Lexicon and Reporting Recommendations

The 2015 consensus statement1 published by the ISMRM Perfusion Study Group and the EU COST Action ‘ASL in Dementia’ aimed to encourage the
implementation of robust Arterial Spin Labeling (ASL) perfusion MRI for clinical applications and promote consistency across scanner types, sites, and studies.
Subsequently, the recommended 3D pseudo-continuous ASL (PCASL) sequence has been implemented by most major MRI manufacturers. However, ASL remains a
rapidly and widely developing field, both in terms of improving the accuracy of cerebral blood flow (CBF) quantification and providing other output derivatives in
addition to CBF. These advances have greatly expanded the scope of ASL, but also bring further divergence of the technique, particularly in the terminology used,
which can lead to confusion and hamper research reproducibility. As part of the Open Science Initiative for Perfusion Imaging (OSIPI), the ASL Lexicon Task Force
has been working on the development of an ‘ASL Perfusion Imaging and Analysis Lexicon and Reporting Recommendations’, aiming: 1) to develop standardized
nomenclature and terminology for the broad range of ASL imaging techniques and parameters, as well as the physiological constants required for quantitative
analysis, and 2) to provide a community-endorsed recommendation on a minimal list of parameters that should be reported in publications.