Objectives To assess agreement between interpretation of magnetic resonance angiography (MRA) and 18F-fluorodeoxyglucose positron emission tomography (PET) for disease extent and disease activity in large-vessel vasculitis (LVV) and determine associations between imaging and clinical assessments.
Methods Patients with giant cell arteritis (GCA), Takayasu’s arteritis (TAK) and comparators were recruited into a prospective, observational cohort. Imaging and clinical assessments were performed concurrently, blinded to each other. Agreement was assessed by per cent agreement, Cohen’s kappa and McNemar’s test. Multivariable logistic regression identified MRA features associated with PET scan activity.
Results Eighty-four patients (GCA=35; TAK=30; comparator=19) contributed 133 paired studies. Agreement for disease extent between MRA and PET was 580 out of 966 (60%) arterial territories with Cohen’s kappa=0.22. Of 386 territories with disagreement, MRA demonstrated disease in more territories than PET (304vs82, p<0.01). Agreement for disease activity between MRA and PET was 90 studies (68%) with Cohen’s kappa=0.30. In studies with disagreement, MRA demonstrated activity in 23 studies and PET in 20 studies (p=0.76). Oedema and wall thickness on MRA were independently associated with PET scan activity. Clinical status was associated with disease activity by PET (p<0.01) but not MRA (p=0.70), yet 35/69 (51%) patients with LVV in clinical remission had active disease by both MRA and PET.
Conclusions In assessment of LVV, MRA and PET contribute unique and complementary information. MRA better captures disease extent, and PET scan is better suited to assess vascular activity. Clinical and imaging-based assessments often do not correlate over the disease course in LVV.
Trial registration number NCT02257866.
- giant cell arteritis
- Takayasu’s arteritis
- magnetic resonance angiography
- positron emission tomography
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Handling editor Josef S Smolen
Contributors KAQ, MAA, AAM, PAM and PCG contributed to the conception and design of this study. KAQ, MAA, AAM, JM, ACC, JSR, AAB, EN and PCG recruited patients into the study and participated in data collection. KAQ, MAA, JSR, AAB and PCG contributed to the data analysis. All authors contributed to data interpretation, critically reviewed the article for important intellectual content and approved the final draft for submission.
Funding This work was supported by the Intramural Research Program at the National Institute of Arthritis and Musculoskeletal and Skin Diseases. KAQ received funding from a Vasculitis Clinical Research Consortium (VCRC)/Vasculitis Foundation Fellowship. The VCRC is part of the Rare Diseases Clinical Research Network, an initiative of the Office of Rare Diseases Research, National Center for Advancing Translational Science (NCATS). The VCRC is funded through collaboration between NCATS and the National Institute of Arthritis and Musculoskeletal and Skin Diseases (U54 AR057319).
Competing interests None declared.
Patient consent Obtained
Ethics approval An institutional review board and radiation safety committee at the NIH approved the research (NCT 02257866).
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement There are no additional data available.
Presented at Part of this manuscript was presented at the 2017 ACR/ARHP Annual Meeting.
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