[Relationship of diffusion kurtosis imaging parameters with the pathologic type and prognosis of rectal tumors].

Objective: To explore the application value of diffusion kurtosis imaging (DKI) in the differential diagnosis of rectal tumors and evaluating the prognostic factors associated with rectal adenocarcinoma. Methods: A total of 105 patients with rectal tumors admitted in the First Affiliated Hospital of Zhengzhou University from December 2018 to August 2020 were retrospectively analyzed. All patients underwent high-resolution magnetic resonance DKI scanning. The mean diffusivity (MD), mean kurtosis (MK) and apparent diffusion coefficient (ADC) were measured and the relationship of these parameters with pathological types and prognostic factors of rectal tumor were analyzed. The diagnostic efficacy of MD, MK, and ADC for positive circumferential resection margin (CRM) and extramural venous invasion (EMVI) of rectal adenocarcinoma was evaluated by the receiver operating characteristic (ROC) curve. Results: MD and ADC were only related to pathological type. The MD and ADC were (2.091±0.390)×10(-3) and (1.478±0.265)×10(-3) mm(2)/s in mucinous adenocarcinoma, higher than (1.136±0.182)×10(-3) and (0.767±0.077)×10(-3) mm(2)/s in unspecified adenocarcinoma and (1.617±0.697)×10(-3) and (0.940±0.179)×10(-3) mm(2)/s in tubulo-villous adenoma. The MD and ADC in unspecified adenocarcinoma were lower than those in tubule-villous adenoma (P<0.05). Nevertheless, MK was associated with pathological type, N stage, CRM and EMVI. The MK was 0.566±0.110 in mucinous adenocarcinoma, lower than 0.982±0.135 in unspecified adenocarcinoma and 0.827±0.121 in tubulo-villous adenoma. The MK in unspecified adenocarcinoma was higher than that in intubulo-villous adenoma. The MK was 0.984±0.107 in pN1-2, higher than 0.881±0.146 in pN0. The MK was 0.990±0.142 in positive CRM, higher than 0.862±0.114 in negative CRM. The MK was 0.996±0.140 in positive EMVI, higher than 0.832±0.100 in negative EMVI (P<0.05). The ROC curves showed that the AUCs of MD, MK and ADC in diagnosing positive CRM were 0.459, 0.653 and 0.408, respectively; with MK=1.006 as the optimal diagnostic threshold, the diagnostic sensitivity and specificity were 51.9% and 81.0%, respectively. The AUCs of MD, MK and ADC values in diagnosing positive EMVI were 0.510, 0.662 and 0.388, respectively; with MK=1.010 as the optimal diagnostic threshold, the diagnostic sensitivity and specificity were 50.9% and 87.5%, respectively. Conclusions: DKI quantitative parameter is helpful for discriminating rectal tubulo-villous adenoma, unspecified adenocarcinoma, and mucinous adenocarcinoma, and is helpful for predicting the prognosis of patients with rectal adenocarcinoma. High MK is associated with positive CRM and EMVI.目的： 探讨扩散峰度成像(DKI)在直肠肿瘤鉴别、直肠腺癌预后相关因素中的应用价值。 方法： 2018年12月至2020年8月郑州大学第一附属医院直肠肿瘤患者105例，行高分辨率磁共振DKI扫描，测量平均表观扩散系数(MD)、平均峰度(MK)及表观扩散系数(ADC)，分析其与直肠肿瘤病理类型及预后相关因素的关系，采用受试者工作特征(ROC)曲线分析评价MD、MK和ADC对直肠腺癌CRM阳性、EMVI阳性的诊断效能。 结果： 在病理类型、分化程度、T分期、N分期、CRM和EMVI这些病理特征中，MD、ADC只与病理类型有关，黏液腺癌MD、ADC分别为(2.091±0.390)×10(-3)和(1.478±0.265)×10(-3)mm(2)/s，高于普通腺癌和绒毛管状腺瘤[分别为(1.136±0.182)×10(-3)和(0.767±0.077)×10(-3)mm(2)/s，(1.617±0.697)×10(-3)和(0.940±0.179)×10(-3)mm(2)/s]，普通腺癌MD、ADC低于绒毛管状腺瘤，差异均有统计学意义(均P<0.05)。而MK与病理类型、N分期、CRM和EMVI均有关，黏液腺癌MK为0.566±0.110，低于普通腺癌和绒毛管状腺瘤(分别为0.982±0.135和0.827±0.121)，普通腺癌MK高于绒毛管状腺瘤；pN1~2期MK为0.984±0.107，高于pN0组(0.881±0.146)；CRM阳性患者MK为0.990±0.142，高于阴性者(0.862±0.114)；EMVI阳性患者MK为0.996±0.140，高于阴性者(0.832±0.100，均P<0.05)。ROC曲线分析显示，MD、MK和ADC诊断CRM阳性的曲线下面积(AUC)分别为0.459、0.653和0.408，以MK＝1.006为最佳界值，MK诊断CRM阳性的灵敏度为51.9%，特异度为81.0%。MD、MK和ADC诊断EMVI阳性的AUC分别为0.510、0.662和0.388，以MK＝1.010为最佳界值，MK诊断EMVI阳性的灵敏度为50.9%，特异度为87.5%。 结论： DKI定量参数有助于鉴别直肠绒毛管状腺瘤、普通腺癌和黏液腺癌，有助于预测直肠腺癌患者的预后，高MK值与CRM阳性、EMVI阳性有关。.