Arthritis & Rheumatism, Volume 63,
November 2011 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Chicago, Illinois November 4-9, 2011.


Whole Body Magnetic Resonance Imaging in Juvenile Spondyloarthritis: Will It Provide Vital Information Compared to Clinical Exam Alone?

Rachlis1,  Alisa C., Babyn2,  Paul S., Lobo-Mueller3,  Edrise, Benseler1,  Susanne M., Stimec4,  Jennifer, Anderson1,  Michelle, Reaume1,  Margaret

The Hospital for Sick Children, Toronto, ON
Saskatoon Health Region, Saskatoon, SK
Hospital for Sick Children, Toronto, ON
Hospital For Sick Children, Toronto, ON

Background/Purpose:

Juvenile-onset spondyloarthritis (JSpAs), referred to as enthesitis-related arthritis (ERA) sub-type under the International League of Associations for Rheumatology (ILAR) classification are characterized by arthritis and enthesitis largely affecting the lower limbs. Clinical exam can be inconclusive and decisions for therapy become difficult. Whole body MRI (WB-MRI) can assess several body regions within a reasonable scan time. The purpose of this study was to evaluate if WB-MRI identifies areas of inflammation seen with JSpAs and agrees with positive findings on clinical exam.

Methods:

Patients diagnosed with ERA (ILAR criteria) followed in the JSpA Clinic at The Hospital for Sick Children (Aug 2008 – Jan 2010) who received a WB-MRI within 3 months of their last clinic visit were included. WB-MRIs consisted of multiple evaluations of 13 regions and were reviewed and scored by consensus of 3 radiologists (PB, ELM, JS). WB-MRIs were correlated to joint and entheseal clinical exam. Arthritis was defined as the presence of synovitis, effusion, or bony erosions (sacroiliac joints (SIs)) and enthesitis as edema in the tendon and bone attachment site. Data were described using means, standard deviations and proportions. MRI results were expressed as detecting more, less or similar findings to clinical exam. Kappa statistics measured agreement.

Results:

There were 23 patients (83% male) with a mean age at diagnosis of 12.6 ± 2.1 years. Time between last clinic visit and WB-MRI was 0.87 ± 0.68 months. A total of 42 active joints and 16 entheses were observed on WB-MRI. Bone marrow edema (BME) like signal changes were most common (83%) with the majority in lower extremities. Arthritis was seen in 70% of patients (SIs most common, 48%), bony erosions in 35% (SIs most common, 22%), synovitis in 22% (ankles most common, 17%), and enthesitis in 26% (hip region most common, 17%). Clinical exam revealed 65% of patients had arthritis and 52% had enthesitis. By all joint sites, WB-MRI detected more findings in keeping with enthesitis in 5%, similar results in 82%, and less in 13% in comparison to clinical exam. WB-MRI detected more arthritis in 7%, similar results in 79% and less in 14% by all joint sites in comparison to clinical exam. While 70% of regions on WB-MRI that reported a positive finding had an associated BME like signal change, 40% of BME sites correlated to either clinical arthritis (88%) or enthesitis (39%). Good agreement (Kappa coefficient > 0.4) was demonstrated for knee, ankle and foot arthritis, and hip region enthesitis.

Conclusion:

The current study demonstrates that WB-MRI identified characteristic lesions expected in our JSpA population. For arthritis, while there was good agreement for peripheral arthritis, WB-MRI was superior to clinical exam for the hips, SIs and spine. For enthesitis, clinical exam over-estimated disease activity in the periphery making WB-MRI an important tool to evaluate entheseal disease. The results of this study illustrate that WB-MRI may become an objective addition to the diagnostic work-up of JSpAs, allowing for assessment of disease presence and severity, monitoring of treatment outcomes and detection of early and subtle inflammatory changes.

To cite this abstract, please use the following information:
Rachlis, Alisa C., Babyn, Paul S., Lobo-Mueller, Edrise, Benseler, Susanne M., Stimec, Jennifer, Anderson, Michelle, et al; Whole Body Magnetic Resonance Imaging in Juvenile Spondyloarthritis: Will It Provide Vital Information Compared to Clinical Exam Alone? [abstract]. Arthritis Rheum 2011;63 Suppl 10 :749
DOI:

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