MRI parametric monitoring of biological therapies in primary large vessel vasculitides: a pilot study.

Objective: To evaluate the development of characteristic MRI changes in patients with primary large-vessel vasculitis (LVV) when treated with biological therapies.

Methods: 12 patients with primary LVV (8 patients with Takayasu arteritis and 4 patients with giant-cell arteritis) received biological therapy with tumour necrosis factor-α blockers (n = 9) or an interleukin-6 inhibitor (n = 3). MRI investigations were performed at baseline (pre-treatment) and follow-up. All patients underwent the same MRI/MR angiography (MRA) protocol. Laboratory parameters (C-reactive protein and erythrocyte sedimentation rate) and clinical response (Birmingham Vasculitis Activity Score) were assessed.

Results: Wall thickness was 4.2 ± 0.3 mm pre-treatment and significantly decreased to 3.2 ± 0.3 mm post treatment in 9/12 patients. Mural enhancement was increased in all 12/12 patients with LVV, and subsided with therapy in 5/12 patients. Mural oedema or ill-defined contour were less prevalent but also improved with biological treatment. C-reactive protein and erythrocyte sedimentation rate levels decreased, and clinical assessment revealed a significant improvement from pre-treatment to post-treatment. However, the course of imaging characteristics often did not parallel that of laboratory or clinical parameters. In all three patients receiving interleukin-6 blockade, laboratory markers and clinical scores normalized despite persistent vascular inflammation in one patient which was disclosed by MRI.

Conclusion: Contrast-enhanced MRI/MRA may be useful when evaluating the development of disease activity in primary LVV under biological therapies. A high degree of suspicion and regular imaging follow-up is needed to detect persistent inflammation.

Advances In Knowledge: This is the first study investigating the applicability of different MRI/MRA parameters for monitoring biological therapy in patients with primary LVV.