磁共振弥散加权成像的表观弥散系数在直肠腺癌术前诊断中的应用

目的 探讨磁共振弥散加权成像(DWI)的表观弥散系数(ADC)在诊断直肠腺癌和评估直肠腺癌恶性程度中的应用.方法 比较82例经病理学检查确诊的直肠腺癌患者(观察组)与82例无直肠病变者(对照组)的ADC值,并在观察组中比较磁共振成像(MRI)和DWI对直肠腺癌T分期诊断的准确性.结果 观察组ADC平均值为(0.89±0.12)×10-3mm2/s,低于对照组ADC平均值(1.45±0.15)×10-3mm2/s,差异有统计学意义(P﹤0.05).对于直肠腺癌的诊断,ADC的最佳分界值为1.26×10-3mm2/s,敏感度为96.1%,特异度为97.5%;低分化、中分化和高分化直肠腺癌的ADC值分别为(0.80±0.10)×10-3mm2/s、(0.95±0.11)×10-3mm2/s和(1.23±0.18)×10-3mm2/s,不同分化程度的ADC值比较,差异有统计学意义(P﹤0.05).对于直肠腺癌,MRI分期诊断的准确性为74.39%,DWI分期诊断的准确性为86.59%,两者比较,差异有统计学意义(P﹤0.05).结论 直肠腺癌的不同分化程度与ADC值相关,DWI可以增加直肠腺癌术前分期诊断的准确率.

Application of apparent diffusion coefficient value of diffusion weighted imaging in preoperative diagnosis of rectal adenocarcinoma

Objective To investigate the application of apparent diffusion coefficient (ADC) value of diffusion weighted imaging(DWI)in the diagnosis of rectal adenocarcinoma and the evaluation of the malignant degree of rectal adenocarcinoma.Method 82 cases of patients with pathologically confirmed rectal adenocarcinoma were enrolled as the study group,and 82 cases of individuals without rectal lesions were included as the control group in the same period.ADC values of the two groups were analyzed,and the accuracy of magnetic resonance imaging(MRI)and DWI in the determi-nation of T stage of rectal cancer was compared.Result The average ADC value of study group was significantly lower than that of the control group(0.89±0.12)×10-3mm2/s vs(1.45±0.15)×10-3mm2/s](P<0.05).The optimal cut-off value,sen-sitivity and specificity of ADC in the diagnosis were 1.26×10-3mm2/s,96.1% and 97.5%,respectively.ADC values of rectal adenocarcinoma with low, moderate and high differentiation were (0.80±0.10)×10-3mm2/s, (0.95±0.11)×10-3mm2/s and (1.23±0.18)×10-3mm2/s,respectively.There were significant differences in ADC values between different differentiated degrees (P<0.05). The accuracy of MRI in staging was 74.39%, while that of DWI was 86.59% (P<0.05). Conclusion The differentiation degree of rectal adenocarcinoma is related to ADC value,while DWI can improve the accuracy in the diagnosis of preoperative stage of rectal adenocarcinoma.