Table 3. Summary of main characteristics and overall risk of bias of studies for monitoring disease activity by ultrasound in Takayasu arteritis.

Study	Inclusion criteria	Patients (n)With follow-up (n) (%)	Time period follow-up	Investigated structures	US key elementary lesions	Summary of main findings	Overall risk of bias
Ma et al17	Clinical diagnosis of TAK*	7777 (100)	12 months	Carotid	Stenosis, occlusion, ↑ IMT, contrast enhancement	Higher IMT in patients with a Kerr/NIH score ≥2.Higher frequency of grade 1 and 2 enhancements in patients with a Kerr/NIH score ≥2; higher frequency of grade 0 enhancement in patients with a Kerr/NIH score <2.Higher frequency of stenosis <50% in patients with a Kerr/NIH score <2	Moderate
Donget al18	Clinical diagnosis of TAK*	115107 (93)	3–6 months	Carotid	Stenosis/occlusion, ↑ IMT, contrast enhancement	Higher IMT and higher external vessel diameter in patients with a Kerr/NIH score ≥2.	Moderate
						Contrast enhancement grade showed a significant correlation with disease activity.
						Patients with grade 3 enhancement had higher ITAS2010 scores
Svensson et al 19	Clinical diagnosis of TAK (new-onset and chronic)*	25All the 9 patients with new-onset disease	1–13 years	Carotid, subclavian, axillary, brachiocephalic, aortic arch	Stenosis, occlusion, ↑ IMT ‘Ultrasound index’	IMT of carotids decreased in patients prescribed with medical treatment, while increased in those prescribed with no treatment.	High
						In seven of the patients (two excluded since they only had axillary stenosis), the ultrasound index significantly decreased between the first and the last evaluation.
						Five patients had a flare (symptoms and/or elevated inflammatory laboratory levels): they all showed a sudden increase of IMT and/or increase of vessel diameter and/or increase of velocities in stenotic areas
Wanget al20	Clinical diagnosis of TAK†	28No follow-up (cross-sectional)	No follow-up (cross-sectional)	Carotid	Stenosis, occlusion,↑ IMT, contrast enhancement	Higher frequency of grade 2 and 3 wall enhancements in patients with a Kerr/NIH score ≥2.	Moderate
						Contrast enhancement grades positively correlated with disease activity, wall thickness and ESR
Li et al 22	Clinical diagnosis of TAK*	71No follow-up (cross-sectional)	No follow-up (cross-sectional)	Carotid	Contrast enhancement	Higher frequency of grade ≥2 wall enhancements in patients with active disease according to the ITAS2010 criteria.	High
						The sum score of two-sided carotid arteries was higher in patients with clinically active disease.
						Total vascularisation score significantly associated with scores on Kerr/NIH criteria and ITAS2010.
						Total vascularisation score significantly associated with levels of CRP and ESR.
						When visual grade ≥2 on FDG-PET/CT was used as the standard for active vasculitis, US had 100% sensitivity and 80% specificity, positive predictive value of 79.2%, and negative predictive value of 100%
Ma et al28	Clinical diagnosis of TAK*	8438 (45)	3 months	Carotid	Stenosis, occlusion, ↑ IMT, contrast enhancement	IMT higher in the active group (according to Kerr/NIH criteria and ITAS2010).	High
						In the inactive group, the proportion of stenosis and occlusion was higher.
						Grade 2 vascularisation higher in patients with active disease.
						Moderate correlation between ESR, CRP, and SAA levels and IMT
Huanget al 29	Clinical diagnosis of TAK*	86Not specified	Not specified	Carotid	Stenosis, occlusion, aneurysm,↑ IMT, contrast enhancement	Higher IMT in patients with a Kerr/NIH score ≥2.	High
						Higher frequency of stenosis in patients with a Kerr/NIH score ≥2.
						Mean enhanced intensity of artery wall higher in patients with a Kerr/NIH score ≥2
Sinhaet al30	Clinical diagnosis of TAK*	19No follow-up (cross-sectional)	No follow-up (cross-sectional)	Carotid, subclavian, renal, femoral, brachial, radial, popliteal, posterior tibial dorsalis pedis, abdominal aorta	Stenosis, occlusion, aneurysm, ↑ IMT, ‘CDUS-K’	Significant correlation between the CDUS-K score and ITAS2010	High
Sethet al34	Clinical diagnosis of TAK†	37No follow-up (cross-sectional)	No follow-up (cross-sectional)	Carotid	↑ IMT	Higher IMT in patients with a Kerr/NIH score ≥2.	High
						US-based measurement of the outer diameter appeared to be not a reliable measure (differentiation between the adventitia and surrounding tissues not clear in almost 70% of patients and intra-observer variability was 30%)
Goudotet al35	Clinical diagnosis of TAK*‡	16No follow-up (cross-sectional)	No follow-up (cross-sectional)	Carotid	Circulating microbubbles (MB)	Higher number of MB per second in patients with a Kerr/NIH score ≥2.	High
						Increased vascular flow rate in patients with a Kerr/NIH score ≥2.
						The number of MB significantly correlated with the carotid SUV max and the carotid-to-liver SUV ratio in FDG-PET/CT
Liu et al31	Clinical diagnosis of TAK*§¶	96No follow-up (cross-sectional)	No follow-up (cross-sectional)	Subclavian, carotid, vertebral	Stenosis, occlusion, aneurysm,↑ IMT/macaroni sign, contrast enhancement	Median SMI grades were higher in patients with a Kerr/NIH score ≥2	High
Lottspeich et al32	Clinical diagnosis of TAK†	17No follow-up (cross-sectional)	No follow-up (cross-sectional)	Subclavian, carotid, axillary	↑ IMT, contrast enhancement	Patients withactive disease had a significantly higher maximum IMT compared with inactive patients and maximum IMT showed a significant correlation to diseaseactivity scores (NIH, ITAS)	Moderate

Retrospective and case–control studies are italicised.

^*1990 ACR criteria.

^†No criteria.

^‡Ishikawa’s criteria modified by Sharma et al.

^§2012 international Chapel Hill Consensus Conference Criteria.

^¶ANCA 2012 Workshop on Takayasu Arteritis criteria.

CDUS, colour doppler ultrasound; CRP, C-reactive protein; ESR, erythrocyte sedimentation rate; FDG-PET/CT, 18F-fluorodeoxyglucose positron emission tomography/CT; IMT, intima-media thickness; ITAS, Indian Takayasu clinical activity score; NIH, National institute of health; SAA, serum amyloid A; TAK, Takayasu arteritis.