探讨克罗恩病（CD）患者小肠CT造影（CTE）影像特征与血清全身免疫炎症指数（SII）及粪便钙卫蛋白（FC）水平的相关性，分析CTE、SII、FC单独及联合检测对疾病活动性的诊断效能。

采用回顾性研究方法，选取2023年1月至2026年5月于苏州大学附属张家港医院消化内科、放射科就诊的208例CD患者为研究对象，通过医院电子病历系统及影像归档系统调取患者临床资料，所有入组患者均同步完成小肠CT造影检查、血清SII相关血常规检测及FC定量检测；由两位具备10年以上腹部影像诊断经验的放射科医师采用盲法独立完成CTE影像特征评估，并据此对患者进行分组，以CD简化内镜评分（SES-CD）作为疾病活动性判断的金标准；采用点二列相关及Spearman秩相关分析CTE影像特征与血清SII、FC的相关性，通过受试者工作特征（ROC）曲线评价各指标单独及联合检测对疾病活动性的诊断效能。

存在分层强化、梳齿征、肠壁溃疡、肠腔狭窄、肠系膜纤维脂肪增生、肠系膜淋巴结肿大CTE阳性影像特征的患者，其血清SII、FC水平均显著高于无对应影像特征的患者（P<0.001）；肠壁越厚、肠壁ΔCT值越高，患者血清SII与FC水平越高，组间差异具有统计学意义（P<0.001）。Spearman秩相关分析显示，所有纳入的CTE影像特征均与血清SII、FC呈显著正相关（P<0.001），其中肠壁厚度与FC的相关性最强（r=0.785）。ROC曲线分析结果显示，基于二元Logistic回归构建的CTE、血清SII、FC三者联合模型诊断CD活动性的曲线下面积（AUC）最高，为0.884，敏感度90.57%，特异度79.63%，显著高于各单项指标（P<0.05）；单项指标中FC诊断效能最优（AUC=0.796），其次为CTE综合影像评分（AUC=0.785），血清SII同样具备良好的诊断价值（AUC=0.742），各单项指标的诊断效能均具有统计学意义（P<0.001）。

CD患者小肠CT造影影像特征与血清SII、FC水平存在显著的正相关关系，CTE、血清SII、FC均可有效评估CD的疾病活动性，三者联合检测可显著提升对疾病活动性的诊断效能，可为临床无创、精准评估CD病情提供可靠的参考依据。

To investigate the correlation between the imaging features of small bowel CT enterography (CTE) and the levels of serum systemic immune-inflammation index (SII) and fecal calprotectin (FC) in patients with Crohn's disease (CD), and to analyze the diagnostic efficacy of single and combined detection of CTE, SII and FC for disease activity.

A retrospective study was conducted. A total of 208 patients with CD who visited the Department of Gastroenterology and Department of Radiology, Zhangjiagang Hospital Affiliated to Soochow University between January 2023 and May 2026 were enrolled as research subjects. Clinical data of the patients were retrieved from the hospital's electronic medical record system and picture archiving and communication system. All enrolled patients underwent small bowel CTE, blood routine tests related to SII and quantitative FC detection simultaneously. Two radiologists with more than 10 years of experience in abdominal imaging diagnosis independently completed the evaluation of CTE imaging features by a blind method, and the patients were grouped accordingly. The Simple Endoscopic Score for CD (SES-CD) was used as the gold standard for the judgment of disease activity. Point-biserial correlation and Spearman rank correlation were used to analyze the correlation between CTE imaging features and serum SII and FC, and receiver operating characteristic (ROC) curve was used to evaluate the diagnostic efficacy of single and combined detection of each index for disease activity.

Patients with positive CTE imaging features including stratified enhancement, comb sign, bowel wall ulceration, intestinal stenosis, mesenteric fibrofatty proliferation, and mesenteric lymphadenopathy had significantly higher serum SII and FC levels than those without the corresponding imaging features (P<0.001). The thicker the bowel wall and the higher the ΔCT value of the bowel wall, the higher the serum SII and FC levels of the patients, with statistically significant differences between groups (P<0.001). Spearman rank correlation analysis showed that all included CTE imaging features were significantly positively correlated with serum SII and FC (P<0.001), among which bowel wall thickness had the strongest correlation with FC (r=0.785). ROC curve analysis showed that the combined model constructed by binary Logistic regression of CTE, serum SII and FC had the highest area under the curve (AUC) of 0.884 for diagnosing CD activity, with a sensitivity of 90.57% and a specificity of 79.63%, which was significantly higher than that of each single index (P<0.05). Among the single indexes, FC had the best diagnostic efficacy (AUC=0.796), followed by the comprehensive CTE imaging score (AUC=0.785), and serum SII also had good diagnostic value (AUC=0.742). The diagnostic efficacy of each single index was statistically significant (P<0.001).

There exists a significant positive correlation between the small intestinal CTE features of patients with CD and their serum SII and FC levels. CTE, serum SII and FC can all effectively evaluate the disease activity of CD. Combined detection of the three indicators can significantly improve the diagnostic efficacy for CD disease activity, and provide a reliable basis for non-invasive and accurate assessment of CD conditions in clinical practice.