Evaluation Of Preoperative Histopathological Features Of Rectal Cancer By Incoherent Motion Magnetic Resonance Imaging In Voxel

Chapter 1 A pilot study on correlations between preoperatiive intravoxel incoherent motion MR imaging and postoperative TNM staging of rectal cancersObjectiveTo explore the role of intravoxel incoherent motion(IVIM)magnetic resonance(MR)imaging in preoperatively predicting the postoperative TNM staging of rectal cancers.Material and MethodsForty-six patients with a diagnosis of rectal cancer through endoscopic biopsy were prospectively enrolled and underwent IVIM MR imaging(12 b values:0-1200 s/mm2)before surgery.Apparent diffusion coefficient(ADC),pure diffusion coefficient(D),perfusion-related incoherent microcirculation(D*)and perfusion fraction(f)values of the lesions were obtained and compared among different postoperative TNM stages.ResultsThere were no significant differences of the IVIM relative parameters among rectal cancers with different TNM stages.ConclusionWe demonstrated that the IVIM relative parameters did not differ among different TNM stages of rectal cancers,which required further confirmation in a larger cohort.Chapter 2 A pilot study on correlations between preoperative intravoxel incoherent motion MR imaging and postoperative histopathological features of rectal cancersObjectiveTo explore the role of intravoxel incoherent motion(IVIM)magnetic resonance(MR)imaging in predicting the histopathological features of rectal cancers preoperatively.Material and MethodsForty-six patients with a diagnosis of rectal cancer through endoscopic biopsy were prospectively enrolled and underwent IVIM MR imaging(12 b values:0-1200 s/mm2)before surgery.Apparent diffusion coefficient(ADC),pure diffusion coefficient(D),perfusion-related incoherent microcirculation(D*)and perfusion fraction(f)values of the lesions were obtained and compared among rectal cancers with different histopathological features,including maximum diameter,pathological type,differentiation degree,lymphovascular and neural invasion status.ResultsThe f and D*values of rectal cancers with lymphovascular invasion(LVI)were significantly higher than those without LVI(P=0.034,0.037,respectively).And.the LVI rate differed significantly among rectal cancers with different pN stages(P=0.003).ConclusionWe demonstrated that the f value derived from IVIM MR imaging might be useful to predict LVI status of rectal cancers preoperatively,which required further confirmation in a larger cohort.Chapter 3 Role of intravoxel incoherent motion MR imaging in preoperative evaluation of DNA mismatch repair(MMR)status in rectal cancersObjectiveTo investigate the role of intravoxel incoherent motion(IVIM)magnetic resonance(MR)imaging in evaluating DNA mismatch repair(MMR)status of rectal cancers preoperatively.Material and MethodsSeventy-six patients of rectal cancers confirmed by endoscopic biopsy were prospectively enrolled and received 3 Tesla MR examination,including IVIM MR imaging(12 b values:0-1200 s/mm2)before any treatment.Apparent diffusion coefficient(ADC),pure diffusion coefficient(D),perfusion-related incoherent microcirculation(D*)and perfusion fraction(f)values of the lesions were obtained.MMR proteins(MMRP),Ki-67,EGFR,VEGF and VEGFR2 expression levels of rectal cancers were confirmed through immunohistochemical staining and microsatellite instability testing on resected specimens.IVIM parameters,Ki-67,EGFR,VEGF and VEGFR2 expression were compared between rectal cancers with different MMRP expression levels.Receiver-operating characteristic(ROC)analysis was performed to evaluate the diagnostic performance of IVIM relative parameters in predicting MMRP expression levels preoperatively.ResultsThe f values of MMRP positive rectal cancers were significantly higher than negative ones(median,0.19(inter-quartile range,0.01)vs.median,0.18(inter-quartile range,0.05),P=0.005).The VEGF and VEGFR2 expression rates of positive MMRP rectal cancers were significantly higher than negative ones(both 57.1%vs.36.8%,P=0.017).The f values could differentiate MMRP positive rectal cancers from negative ones with an area under the ROC curve(AUC)of 0.695(P=0.005).ConclusionsThe f values differed significantly between rectal cancers with different MMRP expression levels,which might be involved with different VEGF and VEGFR2 expression rates.