目的 探讨体素内不相干运动扩 散加权成像参数(IVIM-DWI)对直肠癌患 者术前的指导价值。方法 选取60例直肠 癌患者，获取术前影像学资料。测量并 比较直肠癌肿块与正常直肠组织、不同 TNM分期及不同组织分化程度的标准ADC值 (ADC)、慢扩散ADC值(D)、快扩散ADC值 (D* )、灌注相关体积(f)等参数。结果 直 肠癌肿块的ADC、D值较正常直肠壁均明显 降低(P<0.05)，D*较直肠正常组织明显增 高(P<0.05)；而两种组织f值比较无显著 差异(P>0.05)。随着TNM分期增高，D值 逐渐降低(P<0.05)，而各分期ADC、D* 、 f值比较差异无统计学意义(P>0.05)。 随着分化程度增加，ADC、D值均逐渐增 高，高、中分化ADC值比较无显著差异 (P>0.05)，中、低分化的ADC值比较差异 显著(P<0.05)，而三组D值两两比较均有 显著差异(P<0.05)；三组D* 、f值比较差 异无统计学意义(P>0.05)。结论 IVIM 成像提供的ADC、D、D* 、f等参数，能够 反映肿瘤组织的病理生理状态，尤其是 ADC、D* 值对于术前评 估直肠癌肿瘤分期 与分化程度有重要价值。

Objective To explore the preoperative guiding value of intravoxel incoherentmotion diffusion weighted imaging (IVIM-DWI) in rectal cancer patients. Methods 60 patients with rectal cancer were selected and their preoperative imaging data were obtained. The standard ADC value (ADC), slow diffusion ADC value (D), fast diffusion ADC value (D* ) and perfusion related volume (f) and other parameters were measured and compared in the rectal cancer masses and normal rectal tissues and in the different TNM stages and different degrees of tissue differentiation. Results The ADC and D values in the rectal cancer masses were significantly lower than those in the normal rectal wall (P<0.05), and the D* value was significantly higher than that in the normal rectal tissues (P<0.05). However, there was no significant difference in F value between the two tissues (P>0.05). With the increase of TNM stages, the D value was decreased gradually (P<0.05), but there was no significant difference in the values of ADC, D* and f among different stages (P>0.05). With the increase of differentiation degree, the values of ADC and D were increased gradually, but there was no significant difference in the ADC value between the high differentiation and moderate differentiation (P>0.05), and the ADC value of moderate and poor differentiation was significantly different (P<0.05), and there were significant differences in the D value between the among two group of the three group (P<0.05). There was no significant difference in the values of D* and f among the three groups (P>0.05). Conclusion The ADC, D, D* , f and other parameters provided by IVIM imaging can reflect the pathophysiological state of tumor tissues, especially the ADC and D* values are of important value for preoperative evaluation of stages and differentiation degree of rectal cancer.