Ren Jiayu, Zhu Jiaan, Li Diancheng, Li Wenxue, Liu Fang
Department of Ultrasound, Peking University People's Hospital, Beijing 100044, China.
Quant Imaging Med Surg. 2019 Jun;9(6):1110-1117. doi: 10.21037/qims.2019.06.06.
Ankylosing spondylitis (AS) is a chronic inflammatory disease characterized by high relapse. Therefore, the present study aimed to investigate the ultrasonographic features of contrast-enhanced ultrasonography (CEUS) in the sacroiliac joint (SIJ) in patients with AS in remission after discontinuation of anti-tumor necrosis factor (TNF) therapy, and also examined the role of CEUS in predicting relapse.
In this prospective observational study, 130 SIJs in 65 patients with AS (according to modified New York criteria) satisfying Ankylosing Spondylitis Disease Activity Score (ASDAS) inactive disease after discontinuation of anti-TNF therapy were investigated on color Doppler ultrasonography (CDUS) and CEUS. Vascularization and the resistive index (RI) of the SIJ were observed and measured. We defined no blood flow, high RI of arterial blood flow (RI ≥0.7), the reversed phase in the diastolic phase or venous blood flow in the bilateral SIJs, as negative CDUS/CEUS; meanwhile, low RI of arterial blood flow (RI <0.7) in the unilateral or bilateral SIJs was defined as positive CDUS/CEUS. All the patients were followed up for 52 weeks until relapse. Relapse was defined as an increase of two or more items in comparison with the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) at the time of anti-TNF withdrawal.
After 52 weeks, 46 of the 65 patients (70.8%) had relapse. The mean time to relapse was 31.4 weeks (±8.4 weeks, range 20 to 52). After discontinuation of anti-TNF therapy, positive CEUS accounted for 61.5%; this was significantly more than positive CDUS (13.8%). The vascularization detected by CEUS for patients of relapse was significantly different from that of patients with remission (P<0.05). In addition, patients with negative CEUS had a longer duration of remission than the patients with positive CEUS (P=0.005). A Cox proportional hazards regression analysis found that the disease duration could also be regarded as a factor predictive of relapse in patients with AS.
The use of CEUS distinctly improved the detection of vascularization in the SIJ in patients with AS in remission after anti-TNF withdrawal. The presence of vascularization in the SIJ detected by CEUS at the time of anti-TNF withdrawal could yield a valuable predictor of relapse in patients with AS. A significant limit of this study is the lack of magnetic resonance imaging (MRI) as the standard reference.
强直性脊柱炎（AS）是一种以高复发率为特征的慢性炎症性疾病。因此，本研究旨在探讨抗肿瘤坏死因子（TNF）治疗停药后病情缓解的AS患者骶髂关节（SIJ）的超声造影（CEUS）特征，并研究CEUS在预测复发中的作用。
在这项前瞻性观察研究中，对65例符合改良纽约标准的AS患者（根据强直性脊柱炎疾病活动评分（ASDAS），在停用抗TNF治疗后处于非活动期）的130个SIJ进行了彩色多普勒超声（CDUS）和CEUS检查。观察并测量SIJ的血管化情况及阻力指数（RI）。我们将双侧SIJ无血流、动脉血流阻力指数高（RI≥0.7）、舒张期血流反向或有静脉血流定义为CDUS/CEUS阴性；同时，将单侧或双侧SIJ动脉血流阻力指数低（RI<0.7）定义为CDUS/CEUS阳性。所有患者随访52周直至复发。复发定义为与停用抗TNF时的巴斯强直性脊柱炎疾病活动指数（BASDAI）相比增加两项或更多项。
52周后，65例患者中有46例（70.8%）复发。平均复发时间为31.4周（±8.4周，范围20至52周）。停用抗TNF治疗后，CEUS阳性占61.5%；显著高于CDUS阳性（13.8%）。复发患者CEUS检测到的血管化与缓解患者有显著差异（P<0.05）。此外，CEUS阴性的患者缓解期比CEUS阳性的患者更长（P=0.005）。Cox比例风险回归分析发现，病程也可被视为AS患者复发的预测因素。
CEUS的应用显著提高了停用抗TNF后病情缓解的AS患者SIJ血管化的检测率。停用抗TNF时CEUS检测到的SIJ血管化情况可为AS患者复发提供有价值的预测指标。本研究的一个显著局限性是缺乏磁共振成像（MRI）作为标准参考。
