Vessel wall MRI in giant cell arteritis: standardized protocol and scoring approach developed by an international working group.

Objectives: There are an increasing number of centres performing research on high-resolution vessel wall magnetic resonance imaging (VW-MRI) in GCA. However, harmonized approaches to VW-MRI in GCA are lacking and are essential to performing multicentre studies. Using a data-driven, consensus-based approach, an international expert group developed a standardized MRI protocol and scoring system to advance multi-centred research in cranial GCA.

Methods: A targeted literature review of VW-MRI in cranial GCA was conducted. A working group comprised of radiologists, rheumatologists and ophthalmologists with expertise in VW-MRI and GCA reviewed the results of the literature search, presented relevant data and images from their respective centres, and then reached consensus on recommendations related to key MRI structures, MRI sequences, scoring system and other important considerations.

Results: A total of 21 relevant articles were identified and reviewed. Based on published literature, structures to be evaluated on MRI were categorized based on anatomic location (extradural cranial, intradural cranial and orbits) and prioritization (core vs elective). Essential and elective sequences to comprehensively image cranial and orbital structures while minimizing scan time were determined along with scoring systems to grade contrast enhancement.

Conclusion: This report describes a standardized approach to facilitate research of VW-MRI in cranial GCA that is the result of a multidisciplinary, international collaboration of experts in VW-MRI and/or GCA.