J Rheumatol. 2016 Jan;43(1):75-80.
Evaluation of Magnetic Resonance Imaging Responsiveness in Active Psoriatic Arthritis at Multiple Timepoints during the First 12 Weeks of Antitumor Necrosis Factor Therapy.
- 1From the Department of Rheumatology, Emeritus Research, Victoria; Department of Rheumatology, Institution for Rehabilitation Research, University of Melbourne, Melbourne; Department of Medicine, University of New South Wales, Sydney, Australia.M. Feletar, MBBS, FRACP, Department of Rheumatology, Emeritus Research; S. Hall, MBBS, BSc, FRACP, Department of Rheumatology, Institution for Rehabilitation Research, University of Melbourne, Emeritus Research; P. Bird, BMed (Hons), FRACP, PhD, Grad Dip Magnetic Resonance Imaging, Conjoint Associate Professor, Department of Medicine, University of New South Wales.
- 2From the Department of Rheumatology, Emeritus Research, Victoria; Department of Rheumatology, Institution for Rehabilitation Research, University of Melbourne, Melbourne; Department of Medicine, University of New South Wales, Sydney, Australia.M. Feletar, MBBS, FRACP, Department of Rheumatology, Emeritus Research; S. Hall, MBBS, BSc, FRACP, Department of Rheumatology, Institution for Rehabilitation Research, University of Melbourne, Emeritus Research; P. Bird, BMed (Hons), FRACP, PhD, Grad Dip Magnetic Resonance Imaging, Conjoint Associate Professor, Department of Medicine, University of New South Wales. email@example.com.
OBJECTIVE: To assess the responsiveness of high- and low-field extremity magnetic resonance imaging (MRI) variables at multiple timepoints in the first 12 weeks post-antitumor necrosis factor (anti-TNF) therapy initiation in patients with psoriatic arthritis (PsA) and active dactylitis.
METHODS: Twelve patients with active PsA and clinical evidence of dactylitis involving at least 1 digit were recruited. Patients underwent sequential high-field conventional (1.5 Tesla) and extremity low-field MRI (0.2 Tesla) of the affected hand or foot, pre- and postgadolinium at baseline (pre-TNF), 2 weeks (post-TNF), 6 weeks, and 12 weeks. A blinded observer scored all images on 2 occasions using the PsA MRI scoring system.
RESULTS: Eleven patients completed the study, but only 6 patients completed all high-field and low-field MRI assessments. MRI scores demonstrated rapid response to TNF inhibition with score reduction in tenosynovitis, synovitis, and osteitis at 2 weeks. Intraobserver reliability was good to excellent for all variables. High-field MRI demonstrated greater sensitivity to tenosynovitis, synovitis, and osteitis and greater responsiveness to change posttreatment. Treatment responses were maintained to 12 weeks.
CONCLUSION: This study demonstrates the use of MRI in detecting early response to biologic therapy. MRI variables of tenosynovitis, synovitis, and osteitis demonstrated responsiveness posttherapy with high-field scores more responsive to change than low-field scores.
KEYWORDS: DACTYLITIS; MAGNETIC RESONANCE IMAGING; PSORIATIC ARTHRITIS; PsAMRIS
Psoriatic arthritis is a condition with diverse manifestations encompassing peripheral inflammatory joint disease, enthesitis; tenosynovitis; and axial disease[i]. Magnetic Resonance Imaging (MRI) allows unrivaled assessment of disease activity in diverse structures permitting detailed assessment of the protean manifestations of psoriatic arthritis. In addition, and importantly, MRI permits the assessment of response to therapy for each of each manifestation[ii]. The objectives of this study were to to assess the responsiveness of MRI parameters at multiple time points in the first twelve weeks post anti-TNF therapy initiation in patients with psoriatic arthritis and active dactylitis and to compare high field conventional and extremity low field MRI in the assessment of treatment response in the first twelve weeks of anti TNF therapy in patients with active PsA.
Overall initial scores and score responsiveness were higher for the HF MRI scores for all inflammation parameters.
Tenosynovitis (TS) was observed nine subjects, more easily visualized on HF than LF (Figure 1 Six of these demonstrated reduction in TS score on HF MRI at two weeks with three patients demonstrating marked improvement. (Figure 1-3). The improvement on LF imaging was similar but less striking.
Synovitis was recorded in ten subjects on HF MRI of which eight improved at two weeks with further improvement through twelve weeks. Low field imaging demonstrated lower sensitivity to synovitis and osteitis when compared to high field imaging (Figure 2)).
Osteitis was recorded at low level in seven of eleven HF MRI patients with only one patient (subject eight) demonstrated high osteitis scores at baseline and follow up (Figure 3). Osteitis was recorded on LF MRI examination one one subject at one time point.
These improvements were concordant with clinical findings. High field MRI scores were more sensitive to the presence of inflammatory disease features (tenosynovitis, synovitis, osteitis) and showed greater responsiveness to change than LF MRI scores for these parameters
Of the inflammatory MRI parameters studied, tenosynovitis (TS) was the most prominent, both in terms of identification and responsiveness. Rapid improvements in HF and LF MRI tenosynovitis scores were demonstrated in the majority of subjects at week two, with MRI TS scores continuing to improve over the twelve-week period of treatment in all subjects.
Synovitis scoring provided useful information, with synovitis present in the majority of patients and responsiveness demonstrated. Both MRI tenosynovitis and synovitis are therefore useful parameters, often corresponding with clinical improvement.
Osteitis scoring was also important, providing adjunctive MRI information that is not available on clinical assessment. Therefore although osteitis changes were not as dramatic as tenosynovitis, it is important that osteitis remains within any PsA MRI outcome score as this MRI parameter provides an aperture, providing information regarding disease treatment response that cannot be assessed clinically. It should be noted that the intra-observer agreement for osteitis was lower than synovitis and tenosynovitis. The results however still represent good agreement and are consistent with published intra-reader studies of osteitis in PsA[iii].
High field MRI was more sensitive and responsive to all three MRI inflammation parameters. Baseline TS scores on HF MRI were higher, with greater responsiveness demonstrated at two weeks and over the twelve week treatment period. These most likely reflect the better resolution of HF MRI when viewing relatively small structures such as the tendon sheaths of the fingers and toes.
PsA is a heterogenous disorder and it must be recognized that these small cohort results obtained may not be generalizable to all patients with PsA or even all with dactylitis.
Even with these limitations however, this study provides important objective imaging data in patients with active PsA and their response to anti-TNF therapy.
Figure 4: Proximal PIP joint tenosynovitis and synovitis (arrowed) LF and HF MRI. The images demonstrate the difference in appearance at the same time point. The low field images demonstrates low intensity enhancement, with the high field image showing greater thickness of enhancing synovium and greater intensity of enhancement.
[i] Helliwell PS, Taylor WJ. Classification and diagnostic criteria for psoriatic arthritis Ann Rheum Dis 2005; Suppl II: ii3-ii7
[ii] McQueen F, Lassere M, Duer-Jensen A, Wiell C, Conaghan PG, Gandjbakhch F, et al. Testing an OMERACT MRI scoring system for peripheral psoriatic arthritis in cross-sectional and longitudinal settings. J Rheumatol 2009;36:1811-5.
[iii]. Bøyesen P1, McQueen FM, Gandjbakhch F et al. The OMERACT Psoriatic Arthritis Magnetic Resonance Imaging Score (PsAMRIS) is reliable and sensitive to change: results from an OMERACT workshop. J Rheumatol. 2011 Sep;38(9):2034-8.