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

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

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.

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).

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