The Value Of 3.0 T Magnetic Resonance Diffusion Weighted Imaging To Evaluate The Efficacy Of Rectal Cancer After Preoperative Neoadjuvant Chemoradiation

Objective:To explore the preliminary application value of 3.0 T magnetic resonance diffusion weighted imaging(DWI) in evaluating the effect of preoperative neoadjuvant chemoradiation therapy to rectal cancer.Materials and methods:30 cases of Shanxi Province tumor hospital collected from October 2012 to December2014 were clearly suffering from rectal cancer(confirmed by pathological results), whose MR examination showed a clear lesions, and these patients would be treated with preoperative neoadjuvant chemoradiation, all of them would do routine MR examination and DWI scaning before and after neoadjuvant chemoradiation. According to the compare of preoperative MRI clinical T stage before neoadjuvant therapy and postoperative tumor pathological T stage after treatment, which on the basis of whether the period was droped,these patients were assigend to the tumor downstaged group of 18 cases(18/30, 60 %) and non-downstaged group of 12 cases(12/30, 40%). Thickness, length and ADC values of each group lesions’ maximum level were measured before and after treatment to rectal lesions, then calculated each group’s difference of thickness,length and ADC value before and after the treatment and the rate of change, by the end,compared these differences of two groups.Data were analyzed by paired sample t test and two independent sample t test statistical methods.Results:(1) These values including lesions’ thickness, length and ADC values before and after neoadjuvant chemoradiation to the preoperative rectal cancer were significantly different(P<0.05).(2) These values including lesions’ thickness, length and ADC values for preoperative rectal cancer before neoadjuvant chemoradiation between tumor downstaged group and non-downstaged group were not significantly different(P>0.05).(3) These values including lesions’ thickness difference and change rate, length difference and change rate before and after neoadjuvant chemoradiation for preoperative rectal cancer between tumor downstaged group and non-downstaged group were not significantly different(P>0.05). These values of ADC value difference and change rate before and after neoadjuvant chemoradiation for preoperative rectal cancer were significantly different(P<0.05). If the ADC value difference gotten by using ROC curve can reach 0.207×10-3mm2/s or its change rate reach 0.2066, it can be diagnosed that rectal cancer after preoperative neoadjuvant were therapied to T stage down, its sensitivity was 88.9%and specificity was 83.3%.Conclusion:DWI examination and ADC values measure has important clinical follow-up observation value for rectal cancer patients with preoperative neoadjuvant chemoradiotherapy, through the analysis, can reflect:(1) Through comparing of lesions’ thickness, length and ADC values before and after neoadjuvant chemoradiation to the preoperative rectal cancer, we can conclude that neoadjuvant chemoradiotherapy in the treatment of tumor has a certain effect.(2) Through the quantitative analysis of tumor downstaged group and non-downstaged group’s ADC values change of lesions before and after neoadjuvant chemoradiation, showing that DWI and ADC values of measurement can be used to assess the treatment of rectal cancer preoperative neoadjuvant chemoradiation,which can provide the reference for clinical further treatment of rectal cancer.