Clinical Application Of Magnetic Resonanace Imaging Multiple Sequences In Preoperative Evaluation Of Rectal Carcinoma

Objective To investigation the value of clinical application in preoperative multiple sequences Magnetic Resonance Imaging(MRI)T staging of rectal cancer.Methods The MRI datum of 48 cases of rectal cancer(28 males and 20 females whose ages,62.69 on average,range from 35 to 82)were collected prospectively.A total of 48 patients underwent preoperative MR imaging with phase-array coil at 3.0T MR unit.There are 28 men and 20 women.The average age of patients is 62.69.Turbo spin echo(FS-TSE)T2-weighted sequence,Diffusion weighted imaging(DWI),and contrast enhanced T1-weighted sequence were utilized.The location of rectal cancer was detected and the distance from the inferior margin of cancer to anal verge was measured.We observed Sharpness of lesion display,estimated the infiltrating depth to the bowel wall.Meanwhile,observed the signs of local infiltration of rectal cancer which are third stage or more than it.Finaly we compered the result of MRI to pathological findings.The sensitivity and specificity of MRI in detecting the infiltrating depth to the bowel wall and the accuracy rate of diagnosis were estimated.Results 1.15 lesions located in the upper rectum,23 lesions in the middle rectum,and 10 lesions on the lower rectum.There are 24 lesions belonging to ulcer type,11 lesions belonging to nodular type and 13 lesions belonging to ring-shaped.The diameter of tumor growth following the ascending of differentiated degree of rectal carcinoma.2.The rectal carcinomas are isointense or hypointense in T2-weighted sequence,all of high signal on DWI and enhancement was obvious in contrast enhanced T1-weighted sequence.3.The accuracy of MRI in rectal cancer staging was 83.3%(40/48).The accuracy of stage 3 is 92.3%(24/26).4.In the patients of T4 stage,posterior vaginal wall,posterior uterine wall,peritoneal reflection,Donvilliers fascia and levator ani muscle were infiltrated respectively.Conclusion 1.MRI can depict the extension of the rectal cancer clearly,it can provide a fairly high accuracy rate in T staging.2.The diagnostic reference standard of MRI signs of local infiltration of T4 stage rectal cancer put forward in this study is,to some extent,valuable and helpful to the evaluation of the extent of the circumference invasions of rectal carcinoma,so that it provide envidence to choose the appropriate operations.Objective To observe the correlation of the apparent diffusion coefficient(ADC)value,exponential apparent diffusion coefficient(e ADC)value of MR diffusion weighted imaging(DWI)in differential differentiation of rectal tumor with different b values,and the correlation of ADC value and perineural invasion,peritumor-intravascular cancer emboli in tumor.Method Thirty-two patients with operable rectal cancer underwent preoperative MR imaging with single-shot echo planner imaging(EPI)diffusion-weighted sequences(b=50,500,1000s/mm2).Measure and compare the apparent diffusion coefficient(ADC)value and exponential apparent diffusion coefficient(e ADC)value of MR diffusion weighted imaging(DWI)in rectal wall and differential differentiation of rectal tumor,and the correlation of ADC value and perineural invasion,peritumor-intravascular cancer emboli in tumor.All of them were compared with pathologicstaging.Result 1.The rectal carcinomas lesions show slightly high signal or high signal in DWI.2.When b value is 50,500,1000s/mm2,the mean ADC value of tumor is(2.732±0.805)×10-3mm2/s,(1.226±0.195)×10-3mm2/s,(1.042±0.228)×10-3mm2/s,the mean e ADC value of tumor is(0.097±0.058)mm2/s,(0.304±0.055)mm2/s,(0.363±0.070)mm2/s,respectively.3.With each b values,the mean ADC values of tumor are growth following the ascending of differentiated degree of rectal carcinoma,and,the mean e ADC values are decreases.When b value is 500,1000s/mm2,the difference was statistically significant(b=500 s/mm2,P= 0.03,F= 4.123;b=1000 s/mm2 P=0.001,F=10.797).In most of group,the mean ADC values of peritumor-intravascular cancer emboli and perineural invasion were lower than the negative,and the difference was statistically significant in b=500 s/mm2 of MR diffusion weighted imaging.4.And analyze the Spearson correlation coefficient of differential differentiation of rectal tumor in different b values.The ADC values of tumor and differentiation have positive correlation(rs= 0.742,P<0.05),and have negative correlation with e ADC values(rs=-0.630,P<0.05)with b value of 1000s/mm2.ADC values have the better diagnostic efficiency for diagnosis of rectal adenocarcinoma with b value of 1000s/mm2.Conclusion 1.The diffusion-weighted imaging is a rapid and feasible method in detecting rectal cancer.With each b values,the mean ADC values of tumor are increases following the ascending of differentiated degree of rectal carcinoma,and,the mean e ADC values are decreases.The ADC values of tumor and differentiation have positive correlation,and have negative correlation with e ADC values.The correlation can be pointed out between ADC and pathological classification of each tumor,and the relationship of the ADC value and perineural invasion,peritumor-intravascular cancer emboli in tumor.2.Therefore,the ADC value should respresent a important imaging biomarker for assessing the prognose of the tumor.