AB1124 USEFULNESS OF SUPERB MICRO-VASCULAR IMAGING(SMI) TO DETECT SILENT VASCULITIC DISEASE ACTIVITY IN 2 CASES OF TAKAYASU ARTERITIS
Authors: Y. Okada, T. Kondo, A. Shibata, K. Chino, T. Kurasawa, K. Amano
Journal: Annals of the Rheumatic Diseases (2020)

Background: It is important to use vascular imaging modalities such as CT, MRI and PET-CT to evaluate disease activity of Takayasu arteritis (TAK). In particular, under treatment with tocilizumab (TCZ), redsidual vasculitic disease activity may remain even if serum CRP becomes negative. Contrast-enhanced CT,MRI and PET-CT can evaluate the morphology of blood vessel walls and the distribution of lesions and vasculitic activity, but it is invasive (radiation or contract media exposure), and costly. Ultrasound is superior in terms of morphological evaluation, cost, convenience, and low invasiveness. In particular, Superb Micro-vascular Imaging(SMI) is one of the micro blood flow display methods that can be installed in the ultrasound diagnostic device Aplio series. There are some case reports in which micro blood flow signals of the carotid artery walls were detected using SMI in Takayasu arteritis [1] [2]. Both reports indicate that SMI blood flow is a comparable indicator of disease activity as serum CRP. Objectives: To report the usefulness of SMI in 2 TAK patients who had negative serum CRP but had residual disease activity, leading to appropriate adjustment of treatment. Methods: Two TAK patients who had been newly diagnosed in our department from May 2015 to October 2018 and had received SMI to detect carotid artery wall blood flow signal were retrospectively analyzed. Results: Case 1 A 32-year-old woman developed neck pain, headaches, fever and she had high serum levels of CRP (8.1 mg/dl) and elevated ESR (98 mm/h). Contrast-enhanced CT showed thickening of the carotid artery, left subclavian artery and thoracic aorta and SMI detected blood flow signal in carotid artery wall. Diagnosis of TAK was made. After 2-week treatment with 1 mg/kg/day of PSL, CRP became negative but the micro blood flow in carotid arterity walls was detedted by SMI. Therefore,subcutaneous TCZ (162 mg/week)was added in combination with PSL.One year later, micro blood flow disappeared and we could judge there was no vasculitis activity (Figure A). Before treatment starts 2 weeks after starting treatment One year after starting treatment treatment - PSL 1mg/kg/day ongoing PSL 7mg/day ongoing TCZ 162 mg/week ongoing CRP(mg/dl) + (8.1) −(0.0) −(0.0) SMI signal + + − Figure 1. A. Clinical course of Case 1 Case 2 A 17-year-old woman developed proximal upper limb pain and fever with high serum CRP levels (7.1 mg/dl) and elevated ESR (&gt;110 mm/h), and contrast-enhanced CT showed thickening of the carotid arteries and aortic arch. Two weeks after the start of PSL (1 mg/kg/day), CRP became negative at 0.3 mg/dl, but intramural blood flow detected by SMI remained. Then subcutaneous TCZ was added. Two weeks later, CRP became negative, and the SMI blood flow also disappeared (Figure B). Before treatment starts 2 weeks after starting treatment 4 weeks after starting treatment treatment - PSL 1mg/kg/day ongoing PSL 50 mg/day ongoing TCZ 162 mg/week added CRP(mg/dl) + (7.1) −(0.3) −(0.0) SMI signal + + − Figure 2. B. Clinical course of Case 2 Conclusion: Although SMI has the limitation that it cannot evaluate deep vascular lesions such as aorta, it is neither invasive nor costly and may be a good tool for evaluation of residual vasculitis activity of TAK. References: [1]Sato W, Sato T, Iino T, Seki K, Watanabe H. Visualization of arterial wall vascularization using superb microvascular imaging in active-stage Takayasu arteritis. European Heart Journal - Cardiovascular Imaging . 2019;20(6):719 [2]Ito S, Tahara N, Hirakata S, et al. Signal intensity of superb micro-vascular imaging associates with the activity of vascular inflammation in Takayasu arteritis. Journal of Nuclear Cardiology : Official Publication of the American Society of Nuclear Cardiology . 2019 Mar DOI: 10.1007/s12350-019-01665-4. Acknowledgments: We thank Minako.Yamashita and Masahiro.setoyama for her technical assistance to conduct SMI. Disclosure of Interests: None declared