Evaluation of Takayasu arteritis activity by delayed contrast-enhanced magnetic resonance imaging

Background: To measure and assess the disease activity of Takayasu arteritis (TA) quantitatively by magnetic resonance angiography (MRA).

Methods: Twenty-six Chinese TA patients were divided into an active group and an inactive group. All patients underwent delayed contrast-enhanced MRI. The vessels involved were categorized into type A (main branches of aorta and its arch) and type B (secondary or tertiary branches). Three quantitative scores were defined to gauge lumen stenosis, vessel wall thickness, and vessel wall enhancement, and compared between groups and types.

Results: The patients in the active group had more stenosis in left subclavian artery than those in the inactive group (14/16, 87.5% vs. 2/10, 20%; p<0.01), and greater vessel wall thickness in left common carotid artery (11/16, 68.75% vs. 1/10, 10%; p<0.01) and left subclavian artery (9/16, 56.25% vs. 0/10, 0%; p<0.01). The differences between active and inactive TA were significant in type A (lumen stenosis: 11.13 ± 6.17 vs. 4.00 ± 4.32; p<0.001; wall thickness: 8.00 ± 5.05 vs. 3.10 ± 3.31; p=0.01; wall enhancement: 6.94 ± 5.34 vs. 2.90 ± 4.36; p=0.05), and pronounced in type A+B (lumen stenosis: 13.31 ± 7.19 vs. 6.30 ± 5.60; p=0.02; wall thickness: 8.50 ± 5.29 vs. 3.40 ± 3.34; p=0.01; wall enhancement: 7.94 ± 6.55 vs. 3.20 ± 4.32, p=0.05, respectively). These three scores were moderately correlated to CRP, platelet count and fibrinogen levels (p<0.05).

Conclusions: The MRI scoring system of lumen stenosis, wall thickness and wall enhancement could be a non-invasive approach to facilitate assessment in TA activity.