Comparison of Clinical Parameters and PET/MRI in Juvenile Idiopathic Arthritis

Kathleen Jo Corbin¹, Emily von Scheven¹, Youngho Seo², Spencer Behr² and John MacKenzie³, ¹Division of Rheumatology, Department of Pediatrics, University of California, San Francisco, San Francisco, CA, ²Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, ³Section of Pediatric Radiology, Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA

Meeting: 2016 ACR/ARHP Annual Meeting

Date of first publication: September 28, 2016

Keywords: Imaging, juvenile idiopathic arthritis (JIA), magnetic resonance imaging (MRI) and positron emission tomography (PET)

Session Information

Date: Monday, November 14, 2016

Title: Imaging of Rheumatic Diseases - Poster II: XR/CT/PET/MRI

Session Type: ACR Poster Session B

Session Time: 9:00AM-11:00AM

Background/Purpose: Positron emission tomography (PET) can be used to identify inflammation using ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG). ¹⁸F-FDG uptake correlates with clinical and laboratory markers of disease activity in adults with rheumatoid arthritis and in one previous study of juvenile idiopathic arthritis (JIA). The purpose of this study was to test the feasibility of combining the metabolic data from ¹⁸F-FDG PET with structural and functional data from MRI to assess disease activity in JIA.

Methods: Seven patients with polyarticular JIA according to ILAR criteria (6 RF-positive, 1 RF-negative) underwent ¹⁸F-FDG PET/MRI of the whole body and a dedicated scan of 1 joint/region. Each patient had a complete joint exam on the day of the scan. Patients were scanned using a weight-based, low-dose (0.5 megabecquerel/kg) ¹⁸F-FDG protocol to minimize radiation exposure, resulting in maximum effective dose less than 0.7 millisievert for patients weighing 55 kg or greater. Images were evaluated qualitatively, and joints were considered positive on PET if ¹⁸F-FDG localization was increased above background.

Results: Mean age was 15.1±2.9 yrs and median disease duration was 7.5±2.4 yrs. For 4 out of 7 patients, PET showed more positive joints than physical exam (see table). For 1 patient, physical exam showed 2 positive joints but PET was negative. Joints that showed disagreement between physical exam and PET included hand/wrist, ankle/foot, knee, elbow, and shoulder (see Figure 1). Disagreement between physical exam and PET did not correlate with any clinical characteristics including ESR, BMI, or Juvenile Arthritis Disease Activity Score (JADAS). MRI allowed localization of PET signal, for example allowing diagnosis of tenosynovitis in one patient (see Figure 2).

Conclusion: We found disagreement between physical exam and PET in 5 out of 7 JIA patients. PET detected more joints with inflammation than physical exam, and notably this disagreement often occurred in joints that are easily accessible on physical exam.

Disclosure: K. J. Corbin, None; E. von Scheven, None; Y. Seo, None; S. Behr, None; J. MacKenzie, None.

To cite this abstract in AMA style:

Corbin KJ, von Scheven E, Seo Y, Behr S, MacKenzie J. Comparison of Clinical Parameters and PET/MRI in Juvenile Idiopathic Arthritis [abstract]. Arthritis Rheumatol. 2016; 68 (suppl 10). https://acrabstracts.org/abstract/comparison-of-clinical-parameters-and-petmri-in-juvenile-idiopathic-arthritis/. Accessed .

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