【作者】 郑昊宇；

【导师】 刘筠；

【作者基本信息】 天津医科大学 ， 影像医学与核医学， 2011， 硕士

【摘要】 目的研究常规MRI结合DWI(b=800s/mm2)对直肠癌术前分期的价值,探讨MRI直肠癌T分期征象以及ADC值测量的临床意义。对象和方法对2010年6月至2011年2月期间肠镜确诊为直肠癌的68例病人进行研究。所有病人均行常规MRI及DWI检查。入组标准为：MR检查前未行放化疗及新辅助治疗；检查2周内手术并成功取得标本；所得MR图像清晰可辨。最终58例符合标准,纳入研究。58例中,男性30例、女性28例,年龄为26-78岁,平均为54.4岁。使用PHILIPS公司的Achieva1.5T超导性磁共振成像系统,8通道相控阵表面线圈。患者采用足先进方式,行TSE T1WI横断面、TSE T2WI横断面、T2WI SPAIR横断面(FOV:280×410mm,矩阵：216x260,层厚7mm)。TSE T2WI矢状面(FOV:230×230mm,矩阵：268×225,层厚5mm)；小FOV T2WI横断面(FOV:210×210mm,矩阵：349×333,层厚4mm)；小FOV T2WI冠状面(FOV: 200x200mm,矩阵：284×264,层厚4mmm)；小FOV DWI横断面(FOV:210×210mm,矩阵：128×128,层厚4mm, b=800s/mm2)。统计分析常规MRI结合DWI对直肠癌术前分期的准确率、敏感度、特异度、阳性预测值、阴性预测值以及与病理结果的一致性,评价MRI对直肠癌术前评估的价值。将MRI直肠癌T分期征象与病理结果对照,分析各征象与病理结果相关性,计算MRIT3期各征象诊断的敏感度、特异度、准确率。测量瘤体、瘤旁纤维组织、淋巴结的ADC值,及同层臀部肌肉ADC值,计算瘤体、瘤旁纤维组织、淋巴结的rADC值。对瘤体不同分化程度组ADC值以及rADC值差异进行方差分析。对良恶性瘤旁纤维ADC值以及rADC值进行差异比较；对良性淋巴结、转移性淋巴结ADC值以及rADC值进行差异比较,均采用独立样本t检验,检验水准a=0.05,P<0.05认为有统计学差异。结果对于58例直肠癌病例,常规MRI结合DWI检查T分期准确率为91.4%,N分期准确率为75.9%。T分期与病理结果一致性好,Kappa值0.82。N分期与病理结果一致性中等,Kappa值0.63。直肠癌MRI T分期各级征象与病理分期呈正向线性相关,相关性强(rs=0.874,P<0.01)。壁外索条影、肌层信号中断、肿瘤结节样外凸、系膜脂肪间隙模糊等征象对T3期的准确率分别为67.2%、93.1%、84.5%、72.4%；敏感度分别为64.5%、93.5%、70.9%、77.4%；特异度分别为70.4%、92.6%、100%、66.7%。仅单一阳性征象存在时,壁外索条影和肌层信号中断的准确率分别为37.9%、48.3%。壁外索条影与脂肪模糊征象联合诊断的敏感度为48.3%、特异度77.7%、准确率62.1%；肌层信号中断与脂肪模糊联合诊断的敏感度为77.4%、特异度为92.6%、准确率84.5%；壁外索条与肌层信号中断联合诊断的敏感度为58.1%、特异度为96.3%、准确率为75.8%。壁外索条影、肌层信号中断以及脂肪模糊三征象联合诊断的敏感度为48.4%、特异度为96.3%、准确率为70.7%。直肠癌分化程度提高,所测瘤体ADC值及rADC值随之提高,不同分化程度组间差异有统计学意义(P=0.000)。瘤旁良性纤维增生组与恶性浸润组ADC值及rADC值存在统计学差异,肿瘤浸润组织的ADC及rADC值低于瘤旁反应性纤维组织(P分别为0.016、0.007)。良性淋巴结组的ADC值及rADC值高于转移性淋巴结组,差异均有统计学意义(P=0.001)。结论常规MRI结合DWI检查预测直肠癌术前T分期效果好,预测N分期效果一般。ADC值的测量对不同分化程度直肠癌瘤体、以及瘤旁纤维、淋巴结良恶性的鉴别有一定帮助,同时rADC值对ADC值在以上方面是有用的补充。更多还原

【Abstract】 Objective To study the value of conventional MRI combined with diffusion weighted imaging(DWI)(b=800s/mm2) in preoperative staging of rectal cancer, as well as the value of MRI signs and ADC value for T staging.Materials and methods During Jun.2010 to Feb.2011, Sixty-eight patients with rectal cancer confirmed by the colonoscopy were studied. All patients underwent conventional MRI and DWI examination. Inclusion criterias:no radiotherapy or Neoadjuvant therapy were performed before examination. Operated successfully and obtained specimens within two weeks. MR images were clear enough for assessment. Fifty-eight patients met the standards and enrolled in this study. Among them,30 males,28 females, aged 26 to 78 years, averaged 54.4 years.MR scan were performed in PHILIPS Achieval 1.5T superconductical scanner with 8 channel phased-array surface coil pairs. Feet-first way were applied and all sequences were as follows:axial TSE-T1WI, T2WI, and T2WI SPAIR (FOV: 210x210mm, matrix:349×333, slice thickness:4mm); sagital TSE-T2WI; axial small-FOV T2WI (FOV:210×210mm, matrix:349×333, slice thickness:4mm); coronal small-FOV T2WI(FOV:200×200mm, matrix:286×264, slice thickness: 4mm); axial small-FOV DWI (FOV:210×210mm, matrix:128×128, slice thickness: 4mm, b=800s/mm2).The accuracy, sensitivity, specificity, positive predictive value(PPV), negative predictive value(NPV) and the consistency with pathological results of preoperative rectal cancer prognosised by MRI of all datas were statistical analysed.The correlation between MRI T3 rectal cancer signs and pathological results, accuracy, specificity, sensitivity of all datas were statistical analysed.The ADC values of tumor, paratumor fiber and lymph node were measured, while measured the ADC value of gluteal muscle at the same slice to calculate the rADC values of all of above. The ADC and rADC values for tumor of different differentiated group were analyzed by Analysis of variance(ANOVA) anlysis. The ADC values differences between benign and malignant paratumor fiber, benign and metastatic lymph nodes were compared, respectively. All datas applied Independent sample t test, significance level a=0.05, there were statistically differences when P <0.05 (a=0.05, P<0.05).Results Conventional MRI combined with DWI diagnosing rectal cancer revealed 91.4% accuracy in T staging, 75.9% accuracy in N staging. The consistency between T staging and pathological results were perfect (Kappa=0.82). The consistency between N staging and pathological results were moderate (Kappa=0.63). The relationship between the MRI signs of rectal cancer and the pathological T staging was strong positive(rs=0.874,P<0.01).The total T3 stagging accuracy of lateral rectal wall fiberal strip,disrupted rectal muscular layer, tumor node-like evagination and blurry mesenterium were 67.2%,93.1%,84.5%,72.4%, the sensitivity were 64.5%, 93.5%,70.9%,77.4%, the specificity were 70.4%,92.6%,100%,66.7%, respectively. The accuracy of lateral rectal wall fiberal strip and disrupted rectal muscular layer were 37.9%and 48.3%respectively, when only single sign exist. The sensitivity, specificity and accuracy of Lateral rectal wall fiberal strip combined with blurry mesenterium were 48.3%,77.7%and 62.1%respectively, that of disprupted rectal muscular layer combined with blurry mesenterium were 77.4%,92.6%and 84.5%. while that of lateral rectal wall fiberal strip combined with discontinued hypointensity muscular layer were 58.1%,96.3%, and 75.8%. When three signs above coxisted, that were 48.4%,96.3%and 70.7%.ADC and rADC values varied among different differented tumors as the tumor, and the discrepancies of the ADC values between different tumor degrees were statistically different(P=0.000). The discrepancies of ADC values between benign and malignant paratumor fibers were statistically different(P=0.016,0.007). The ADC and rADC values of benign lymph nodes were larger than malignant lymph nodes, and the discrepancies were statistically different(P=0.001).Conclusions Conventional MRI combined with DWI had a agreat role in preoperative T stagging of rectal cancer, on the contrary, had an unsatisfied role in N stagging. The measurement of ADC value was useful for differentiating the degrees of rectal cancer and judge the malignancy of peritumoral fibers and lymph nodes, while the rADC values were effective supplement for ADC values.更多还原