The Value Of Diffusion-weighted MRI In Judging The Aggressiveness And Prognosis Of Rectal Cancer

Background and Aims: Rectal cancer is one of the most common malignant tumor.DW-MRI plays a great role in finding and diagnosing rectal cancer.This study explore the value of DWI and ADC in the relationship between the malignant degree, aggressiveness and prognosis of rectal cancer,in order to provide an imaging basis for the clinical treatment.Materials and Methods:Between March 2014 and December 2014, 32 consecutive patients were considered for inclusion in this retrospective study.Inclusion criteria were(1) histologically(biopsy) proven rectal carcinoma,(2) treatment by surgical resection.28 cases were malignant lesions,4 cases were benign lesions.Patients were imaged in a 3.0Tesla(T) MR magnet.The imaging protocol consisted of standard protocol,DCE imaging and diffusion-weighted imaging,b-vale use:0,800 s/mm2.Describing the morphological features of the lesions such as morphology and edge,measuring the short diameter of the lymph node.The ADC measurements were performed in the adw 4.4 workstation.Results:The mean ADC values are statistically significant between the benign and malignant lesions in rectal cancer.The mean tumor ADC is 1.378±0.098×10-3mm2/s for the benign lesions,0.938±0.151×10-3mm2/s for the malignant lesions.The mean ADC values are also statistically significant in different differentiation degree in rectal cancer(1.153±0.077×10-3mm2/s for high,0.966±0.09×10-3mm2/s for medium,and0.774±0.038×10-3mm2/s for low differentiation).In evaluating of CRM invasion,the sensitivity, specificity,accuracy,PPV and NPV is 76.9%,80%,78.5%,76.9%,and 80%respectively.In the CRM(+) cases,The mean tumor ADC is 0.876±0.112×10-3mm2/s,and it is 0.992±0.163×10-3mm2/s in the CRM(-) cases(P<0.05).The average short diameter of the malignant and benign nodes has no statistical differences(6.0±1.6mm,range:3-8mm vs. 6.2±2.9mm,range 4-17mm).The mean ADC of the malignant and benign nodes did differ(0.919±0.142×10-3mm2/s vs. 1.04±1.86×10-3mm2/s),(P=0.014. AUC 0.705).The sensitivity, specificity,NPV,PPV and accuracy is 71.7%,66.7%,42.3%,84%,and 69%respectively.Conclusions:DWI and the mean ADC values of tumor and lymph nodes can help judging the T- and N-stage,and evaluating CRM invasion.Which has a certain significance for predicting the prognosis of the patients.