双能量CT对肠系膜脂肪在克罗恩病活动性评估的价值研究

Study on the value of dual-energy CT in evaluating the activity of mesenteric fat in Crohn′s disease

目的探讨双能量CT定量分析肠系膜脂肪在克罗恩病(CD)活动性评估中的价值。方法回顾性分析40例确诊为CD的患者资料,根据CD活动性指数(CDAI)将患者分为活动期组(CDAI≥150)和缓解期组(CDAI<150)。分别测量两组病变肠壁周围肠系膜脂肪CT值、碘密度和脂肪百分比。对CT值和脂肪百分比进行受试者工作特征(ROC)曲线分析,计算其最佳阈值、灵敏度和特异度。使用Speraman分析评估CT参数与C反应蛋白(CRP)的相关性。结果该研究共纳入活动期组13例,缓解期组27例。活动期组肠段36个,缓解期组肠段72个。活动期组肠系膜脂肪CT值[-(66.371±16.498)HU]高于缓解期组[-(81.502±12.435)HU],差异有统计学意义(P<0.05)。活动期组肠系膜脂肪百分比[(80.998±5.059)%]低于缓解期组[(88.852±5.179)%],差异有统计学意义(P<0.05)。两组碘密度比较,差异无统计学意义(P>0.05)。CT值的灵敏度和特异度分别为69.4%和87.5%,曲线下面积为0.777;脂肪百分比的灵敏度和特异度分别为79.2%和83.3%,曲线下面积为0.862。脂肪百分比与CRP呈负相关,CT值、碘密度与CRP无相关性。结论肠系膜脂肪定量分析有助于CD活动性评估。

Objective To explore the value of dual-energy CT quantitative analysis of mesenteric fat in the assessment of Crohn′s disease activity.Methods A retrospective analysis of 40 patients diagnosed with Crohn′s disease was conducted.According to Crohn′s disease activity index(CDAI),the patients were divided into the active group(CDAI≥150)and the remission group(CDAI<150).CT value,iodine density and fat fraction of mesenteric fat around the diseased bowel wall were measured in the two groups.Receive receiver operating characteristic(ROC)curve was used to analyze CT value and fat fraction,and calculated the optimal threshold,sensitivity and specificity.Speraman analysis was used to evaluate the correlation between CT parameters and C reactive protein(CRP).Results This study included 13 cases in the active group and 27 cases in the remission group,while there were 36 intestinal segments in the active group and 72 in the remission group.CT value of mesenteric fat[-(66.371±16.498)HU]in the active group was higher than that in the remission group[-(81.502±12.435)HU],the difference was statistically significant(P<0.05).The fraction of mesenteric fat in the active group[(80.998±5.059)%]was lower than that in the remission group[(88.852±5.179)%],the difference was statistically significant(P<0.05).There was no significant difference in iodine density between the two groups(P>0.05).The sensitivity and specificity of CT values was 69.4%and 87.5%,respectively,and the area under the curve was 0.777;the sensitivity and specificity of fat fraction was 79.2%and 83.3%,respectively,and the area under the curve was 0.862.Fat fraction was negatively correlated with CRP,while CT value and iodine density had no correlation with CRP.Conclusion Quantitative analysis of mesenteric fat in Crohn′s disease is helpful to evaluate CD activity.