High-resolution Magnetic Resonance Imaging Staging Of Rectal Cancer Diagnosis And Preoperative Value

objective: to evaluate the value of high resolution MR imaging with diffusion weighted imaging in the preoperative diagnosis of rectal cancer, the clinical value of high resolution MR imaging in the T staging and the value of signal attenuation ratio and apparent diffuse coeffieient in diagnosis.Materials and methods: 60 patients with rectal cancer(confirmed by pathology)were performed with high resolution MR imaging examinations before surgical operation,and with diffusion weighted imaging(b=600.1000s/mm2). The apparent diffusion coefficient(ADC) and signal attenuation ratio(SAR)of the tumors were measured. select 15 patients without rectal cancer,ADC and SAR value of the tumors and normal rectal wall were measured .Results:(1)The areas under ROC was 0.927 for high resolution MR imaging alone and 0.996 for DWI with high resolution MR imaging,two methods of diagnosis accuracy are very high.High resolution MRI diagnosis rectal cancer sensitivity, specific degree and coincidence rate were 65%,100%,72%, High resolution MRI with DWI diagnosis colorectal cancer sensitivity, specific degree and coincidence rate were 91.7%,100%,93.3%.(2)The high resolution MRI tumor T-staging agreed with the histological stage that was 90.0%, the diagnosis of T2 stage was 78.3%,the diagnosis of T3 stage was 96.7%,diagnosis of T4 stage was 100%.The high resolution MRI tumor T-staging and postoperative pathologic T-staging have good consistency( kappa=0.835,P=0.000)(.3)The same b-valued under The ADC values and SAR values of rectal cancer tumors and the control group rectal were difference (P < 0.05);the optimal threshold for ADC of rectal cancer tumors were 1.856×10-3mm/s2 and 1.701×10-3mm/s2at different b-valued.The discrepancies in ADC values and SAR values among the rectal cancer with different differentiations were compared statistieally.There were positive correlations between SAR values and ADC values(P<0.05).(4)No statistically significant difference was found at the distance between the the lower edge of thetumor and the anal margin measured by MRI and and by operational specimen (P>0.05).Conclusion: High-resolution MRI with DWI for the rectal cancer preoperative diagnosis and T-staging has higher diagnostic accuracy,ADC values and SAR values were quantitative analysis of rectal cancer, DWI can serve as an important supplement sequence of colorectal cancer diagnosis.