Objectives: The role of ultrasonography for evaluating vessel wall inflammation in Takayasu's arteritis (TAK) is well-recognised; however, an effective approach for the quantitative assessment of disease activity remains lacking. This study aimed to develop a novel ultrasound-based score for determining TAK activity.
Methods: TAK patients with carotid artery involvement were prospectively followed-up for 6 months. Our proposed ultrasonographic activity score (ULTRAS, range between 0-12) consisted of wall thickness (TS, range between 0-8) and semi-quantitative echogenicity scores (ES, range between 0-4). The diagnostic performance of ULTRAS for disease activity was evaluated in terms of area under the receiver operating characteristic curve (AUC). Internal validation was subsequently performed.
Results: The patients were divided into training and validation groups (n=136 and 30. respectively). In the training group, 83 (61.0%) had active disease. At an optimal cut-off of 7, ULTRAS showed good diagnostic accuracy for active TAK (AUC, 0.88; 95% CI, 82-94). Improved diagnostic performance was achieved when combined with ESR (AUC, 0.91; 95% CI, 86-96) or CRP (AUC, 0.90; 95%CI, 86-95). In the verification group, the AUCs were 0.88, 0.95, and 0.92 for ULTRAS, ESR plus ULTRAS, and CRP plus ULTRAS, respectively. At post-treatment follow-up, the TS, ES, and ULTRAS paralleled the patients' disease remission and symptom recovery. At 3-month follow-up, an improvement in wall thickness of ≥0.3 mm correlated with symptom recovery in 50% of the patients.
Conclusions: Our proposed ultrasound-based score carries the potential in the detection of active disease among TAK patients.