磁共振弥散加权成像观察胰腺癌冷冻术后近期疗效的应用价值

摘要

Objective To discuss the clinical value of magnetic resonance diffusion-weighted imaging (MR-DWI) in distinguishing tumor remnants from tumor necrosis of pancreatic carcinoma after cryoablation treatment.Methods Conventional MRI T1WI,T2WI scan,DWI sequence and dynamic enhanced MRI scan were performed in 26 patients with pancreatic carcinoma who were received cryoablation treatment.The changes in MRI signals after cryoablation treatment were recorded.The apparent diffusion coefficient (ADC) values of the normal pancreas,preoperative tumor tissue,postoperative remnants and necrosis tissue were calculated,and the results were compared.The correlation between the ADC values and the size of the tumor was evaluated,and the differences in ADC values among the tumors that had different diameter,location and staging were statistically analyzed.Results Of the 26 patients,complete necrosis of tumor was obtained in 16.The necrotic tumor tissue displayed low-signal on T1WI,high-signal on T2WI and low-signal on DWI,with no enhancement on dynamic enhanced imaging.Active residual tumor tissue was detected in 9 patients,among them the residual tumor diameter ＞5 cm was seen in 7 patients;the residual rate was 34.6％.ADC values of the following tissue,from low to high in order,were preoperative pancreatic tumor tissue (1.022± 0.126)x10-3 mm2/s,postoperative residual tumor tissue (1.130±0.155)x10-3 mm2/s,normal pancreatic tissue (1.924±-0.124)×10-3 mm2/s and postoperative necrosis tissue (2.312-±0.214)×10-3 mm2/s.No statistically significant difference in ADC values existed between preoperative pancreatic tumor tissue and postoperative residual tumor tissue (P=0.452),while statistically significant difference in ADC values existed between normal pancreatic tissue and postoperative necrosis tissue (P＜0.001).The ADC values of pancreatic tumor tissue bore a negative correlation with the tumor size (R=-0.43,P=0.027 2),while the ADC values lacked the relationship to the tumor location as well as to the tumor staging (P=0.738 8 and P=0.089 5 respectively).Conclusion MR-DWI can effectively distinguish the residual tumor tissue from the necrotic tumor tissue of pancreatic carcinoma after cryoablation treatment,which provides reliable basis for further clinical diagnosis and treatment.%目的 探讨采用磁共振弥散加权成像(MRI-DWI)评估胰腺癌冷冻术后肿瘤坏死及肿瘤残存的应用价值.方法 对接受冷冻治疗的26例胰腺癌患者行T1WI、T2WI常规MRI平扫、DWI序列及动态增强扫描.观察胰腺癌冷冻前后MRI信号改变.测量并比较正常胰腺、术前肿瘤组织及术后残存、坏死组织的表现弥散系数(ADC)值.评价肿瘤组织ADC值与肿瘤大小的相关性,不同肿瘤直径、肿瘤位置及分期表现ADC值的差异.结果 26例患者中16例肿瘤完全坏死,冷冻坏死的胰腺肿瘤组织在T1WI图像上呈低信号,T2WI呈高信号,DWI呈低信号,动态增强无强化.活性肿瘤组织残留9例(其中7例肿瘤直径＞5.0 cm),残留率为34.6％.ADC值由低到高依次为:术前胰腺肿瘤组织(1.022±0.126)×10-3 mm2/s、术后残存肿瘤组织(1.130±0.155)×10-3 mm2/s、正常胰腺组织(1.924±0.124)×10-3 mm2/s及术后坏死组织(2.312±0.214)×10-3 mm2/s.术前胰腺肿瘤组织ADC值与术后残存肿瘤组织相比,差异无统计学意义(P=0.452),与正常胰腺组织、术后坏死组织相比,差异有显著统计学意义(P＜0.001).胰腺肿瘤ADC值与肿瘤大小呈负相关(R=-0.43,P=0.027 2),与肿瘤位置、肿瘤分期无关(P=0.738 8,P=0.089 5).结论 DWI能有效鉴别胰腺癌冷冻治疗后的病灶坏死及残存,为进一步临床诊治提供依据.