Mural inflammatory hyperenhancement in MRI of giant cell (temporal) arteritis resolves under corticosteroid treatment

Objective. To determine the effect of corticosteroid treatment on mural inflammatory hyperenhancement in MRI in GCA. Methods. MRI of the superficial temporal artery with sub-millimetre in-plane spatial resolution (195 x 260 mu m) was performed in 17 patients with proven GCA at the initiation of corticosteroid treatment and after 16 months of therapy. Visual MRI scores for mural inflammation were correlated with clinical and laboratory findings. Results. Intensity of inflammatory hyperenhancement decreased significantly under corticosteroid therapy (2.3 +/- 0.6 vs 0.5 +/- 0.6, P < 0.001, with MRI score > 2 indicating vasculitis). This finding correlated with the clinical and serological remission in 15/17 patients. Of the two patients with active disease, one had persisting mural inflammation in MRI indicative of relapsing disease. The other patient presenting with signs of polymyalgia rheumatica had no inflammatory changes of the superficial temporal arteries on MRI scan at follow-up. Conclusions. Mural contrast enhancement in high-resolution MRI is pronounced in active disease and decreases under corticosteroid treatment, correlating well with laboratory remission.