Clinical Value And Study Of High-resolution MRI And Diffusion-weighted MRI In Rectal Cancer

Part one Value of high-Resolution MRI for Depicture RectalCancer-Related Anatomy StructuresObjectiveTo investigate the value of high-resolution MRI for depicture rectal cancer-relatedanatomy structure.Material and MethodsThe institutional committee of ethics approved this study and all the subjects signedinformed consent. Conventional MR imaging and high-resolution transversal and sagitalT2WI were performed in10health volunteers and46patients with histopathologicalconfirmed rectal cance. Visualization of rectal cancer-related anatomy structures wasassessed on high-resolution T2WI.ResultsHigh-resolution T2WI depicted front, back, left and right total mesorectal fascia（TheMesorectal Fascia） in73.4%,100%,97.9%and97.6%of the56subjects, respectively.The rate of visualization of the retrorectal space, the rectosacral fascia, thedenonviliiers’ fascia and the peritoneal reflection was100%,81.1%,100%and86.2%,respectively.ConclusionHigh resolution MRI can shows rectal cancer related anatomical structures legibly,which is essential for local stage. Part two Value of High-Resolution MR Imaging Plus DWI forPreoperative Local Staging of Rectal CancerObjectiveTo investigate the value of high-resolution MRI plus DWI for preoperative localstaging of rectal cancer.Material and MethodsThe institutional committee of ethics approved this study and all the subjects signedinformed consent. Forty six consecutive patients, who had surgery and pathologyconfirmed with rectal cancer and received MR imaging including high-resolution T2WIand DWI before operation, were enrolled in this study. Two experienced diagnosticradiologists reviewed two sets of MR images （high-resolution T2WI alone andhigh-resolution T2WI plus DWI） in consensus before operation. Using histopathologicalfindings as standard, accuracy was calculated and McNemar test was used to comparethe difference.ResultsThe accuracy of T stage of high-resolution T2WI plus DWI and high-resolutionT2WI alone was84.7%and68.4%, respectively. The difference was statisticalsignificant （T P=0．041）. The accuracy of N stage high-resolution T2WI plus DWI vshigh-resolution T2WI alone was82.6%vs60.9%with statistical significance（P=0．032）.ConclusionCombination Adding DWI to high resolution MRI can improve the accuracy oflocal stage of rectal cancer which provides guides for accurate staging, respectabilityassessment, and therapy plan making of rectal cancer. Part three A Study of Correlation of ADC Value andHistopathological Grading of Rectal CancerObjectiveTo evaluate the relationship of apparent diffusion coefficient （ADC） value withhistopathological type and grading of rectal cancerMaterial and MethodsThe institutional committee of ethics approved this study and all the subjects signedinformed consent. Forty six consecutive patients, who had surgery and histopathologicalconfirmed with rectal cancer and received MR imaging including high-resolution T2WIand DWI before operation, were enrolled in this study. The relationship between ADCand histopathological type was evaluated using the Mann-Whitney U test. One–wayANOVA was used to compare differences of ADC among histopathological gradings,followed by spearman rank correlation.ResultsThe46rectal caners consisted of mucinous adenocarcinoma in8patients andadenocarcinomas in35patients. The35cases of adenocarcinoma were highdifferentiation in10, medium differentiation in18, and low differentiation in7. TheADC values of adenocarcinoma and mucinous adenocarcinoma was （1.088±0.347）×10^-3mm²/s and （1.238±0.326）×10^-3mm²/s, respectively. The difference wasstatistical significant （u=141.5,p=0.032）. The ADC of high, medium andlow differentiate adenocarcinoma is （1.195±0.387）×10^-3mm²/s,（1.036±0.187）×10^-3mm²/s and （0.964±0.312）×10^-3mm²/s， respectively. Thedifference of ADC among the different differentiate adenocarcinmas was statisticalsignificant （F=3.393,P=0.039）. spearmen rank test revealed an reverse relationship ofADC value to histophathological grading （r=-0.745,p=0.013） ConclusionADC value has shown to be correlated to histopathological type and grading. It hasthe potential possibility to become a biomarker for histopathological type and gradingof rectal cancer.