Comparing Psoriatic Arthritis Low-field Magnetic Resonance Imaging, Ultrasound, and Clinical Outcomes: Data from the TICOPA Trial.

Objective: The Tight Control of inflammation in Psoriatic arthritis (TICOPA; isrctn.com: ISRCTN30147736) trial compared standard care (StdC) and tight control (TC) in early psoriatic arthritis (PsA), demonstrating better outcomes for TC. This substudy evaluated the performance metrics of modern imaging outcomes and compared them to the clinical data.

Methods: Non-contrast 0.2T magnetic resonance imaging (MRI; single hand) was assessed using the Outcomes in Rheumatology (OMERACT) PsA MRI Scoring System (PsAMRIS) with an additional global inflammation score. Ultrasound (US; same hand) was scored for greyscale, power Doppler, and erosions at the metacarpophalangeal (MCP) and proximal interphalangeal (PIP) joints and scores summated.

Results: Seventy-eight patients had paired (baseline and 48 weeks) US data and 61 paired MRI data; 50 had matched clinical, MR, and US data. Significant within-group changes were seen for the inflammatory PsAMRIS components at MCP level: MRI global inflammation [median difference (range), standardized response mean (SRM)]: 3.25 (-5.0 to 12.0), 0.68; 1.0 (-4.5 to 17.5), 0.45 for TC and StdC, respectively. Similar within-group differences were obtained for US: 1.0 (-13.0 to 23.0), 0.45; 3.0 (-6.0 to 21.0), 0.77 for TC and StdC, respectively. No differences were seen between treatment groups. Significant correlations were found between baseline and change MRI and US scores. A significant correlation was found between baseline PsA disease activity scores and MRI global inflammation scores (Spearman ρ for MCP, PIP: 0.46, 0.63, respectively). No differences in erosion progression were observed.

Conclusion: The PsAMRIS and US inflammation scores demonstrated good responsiveness. No between-group differences were demonstrated, but this substudy was likely underpowered to determine differences between the 2 treatment strategies.