光谱CT定量动脉增强分数及细胞外容积多参数定量评估对结直肠癌诊断的价值

目的  探讨光谱CT定量增强参数对结直肠癌的诊断价值。方法  对46例行腹盆部光谱CT三期增强的结直肠癌患者的能谱基数据进行处理，生成无水碘图、动脉增强分数（AEF）图及细胞外容积（ECV）图，分别测量肿瘤及正常肠壁的碘浓度（IC）、AEF及ECV值。采用独立样本t检验及Mann-Whitney U检验进行组间比较，并采用ROC曲线评价其诊断效能。结果  结直肠癌病变的AEF及IC值大于正常肠壁AEF值及IC值（0.338±0.122 vs 0.225±0.072，1.007±0.402 mg/mL vs 0.599±0.229 mg/mL，P＜0.0001），ECV在结直肠癌病变与正常肠壁间的差异无统计学意义（P＞0.999）。AEF、IC、ECV及三者联合诊断结直肠癌的ROC曲线下面积分别为0.806、0.797、0.671及0.842，其约登指数分别为0.565、0.565、0.326及0.609。三者联合诊断结直肠癌的截断值为0.660，敏感度为63.04%，特异性为97.83%，其逻辑回归方程为Y=13.75×AEF+16.30×ECV-6.70。结论  光谱CT定量增强参数AEF、ECV及IC联合诊断对结直肠癌的诊断具有一定价值。

Value of quantitative multi- parameter assessment of arterial enhancement fraction and extracellular volume based on the iodine maps on spectral CT in the diagnosis of colorectal cancer

Objective To explore the diagnostic value of quantitative contrast-enhanced parameters of spectral CT in colorectal cancer. Methods Spectrum base images of 46 patients with colorectal cancer who underwent three- phase enhancement of abdominal and pelvic spectral CT were processed to generate the water-free iodine images, arterial enhancement fraction (AEF) and extracellular volume (ECV) images, and the iodine concentration (IC) value, AEF value and ECV value were measured on the colorectal lesions and the normal colorectal walls. The independent sample t test and Mann-Whitney U test were applied for inter-group comparisons, and ROC curve was used to evaluate the diagnostic efficacy. Results The AEF value and IC value presented significantly highly in the patients than that in normal intestinal wall (0.338±0.122 vs 0.225±0.072, 1.007±0.402 mg/mL vs 0.599±0.229 mg/mL, P < 0.0001). ECV showed no significant difference between colorectal lesion and the normal intestinal wall(P > 0.999). The areas under the ROC curve of AEF, IC, ECV and three indicators combination in the diagnosis of colorectal cancer were 0.806, 0.797, 0.671 and 0.842, respectively, and the Jordan index were 0.565, 0.565, 0.326 and 0.609, respectively. The cutoff value of three indicator combination in the diagnosis of colorectal cancer was 0.660 with the sensitivity of 63.04% and the specificity of 97.83%, and the logistic regression equation was Y=13.75×AEF+16.30×ECV-6.70. Conclusion The combined diagnostic model of spectral CT quantitative contrast-enhanced parameter of AEF, ECV and IC has certain value in the diagnosis of colorectal cancer.