A Study Of Applicational The Value Of Small Field-of-view T2WI And DCE-MRI In Rectal Adenocarcinoma

Background Rectal cancer is a common types of malignant cancer with high incidence and mortality.With the improvement of living standards,diet and lifestyle changes.the incidence and mortality of rectal cancer in China are gradually increasing.Magnetic resonance imaging(MRI)is widely used in preoperative diagnosis of rectal cancer due to its advantages in soft tissue resolution,multi-location and multi-sequence imaging.Conventional magnetic resonance imaging scan technology can well show the scope and depth of the tumor,but can only analysis rectal lesions from morphological,that can not evaluate internal microenvironment of rectal lesions with functional methods.Dynamic contrast-enhanced magnetic resonance imaging(DCE-MRI)is a non-invasive functional examination method magnetic resonance imaging,based on the evaluation of tumor microcirculation perfusion status,combining the hemodynamic changes and histomorphology,so as to realize the tumor pathological characteristics of evaluation.Part1 Clinical application of small field-of-view T2 WI in rectal carcinoma T stagingObjective To investigate the value of small field-of-view T2 weighted imaging(T2WI)in rectal carcinoma T staging.To provide more information for the selection of individualized treatment options for rectal cancer.Materials and methods 90 cases with rectal adenocarcinoma patients confirmed by colonoscopy biopsy underwent 3.0T MRI examination,including conventional T2 weighted imaging and small field-of-view,thin-section T2 weighted imaging.Their clinicopathologic data were collected.All original data were send to GE ADW 4.6 workstation.Small field-of-view T2 weighted imaging were used to perform T staging of rectal cancer,and Kappaanalytical method was used to analyze the consistency between T staging by small field-of-view T2 weighted imaging and pathological stage.Results Small field of view T2 weighted imaging for T stage were highly consistent with pathological stage(Kappa=0.771).The diagnostic accuracy in predicting T stage was 84.44%.The accuracy,sensitivity and specificity for tumor of T1~T2 stage were 90.00%、86.67%、91.67%,respectively.the accuracy,sensitivity and specificity for tumor of T3 stage were86.67%、82.05%、90.20%,respectively.the accuracy,sensitivity and specificity for tumor of T4 a stage were96.67%、95.24%、97.10%,respectively.Conclusion Small field-of-view T2 WI has relatively high application value in rectal carcinoma T staging,as well as in the tumor T staging evaluation before surgery and the selection of therapeutic schedule.Part2 The Study of Applicational value of DCE-MRI perfusion Parameters in rectal CarcinomaObjective To explore the applicational value of DCE-MRI quantitative parameters and semi-quantitative parameters in staging and differentiation of rectal carcinoma.Materials and Methods 49 cases with rectal adenocarcinoma patients confirmed by colonoscopy biopsy underwent 3.0T MRI examination,including conventional T2 weighted imaging andDCE-MRI examination.Their clinicopathologic data were collected.All data obtained from the DCE-MRI sequences were sent to the Omni Kinetce workstation for post-processing,using the Tofts pharmacokineticmodel for quantitative parameters,including volume transfer constant from the plasma compartment to the extravascularextracellular space(Ktrans),rate constant for transferbetween the extravascular extracellular space and the bloodcompartment(Kep),volume of extravascular extracellularspace per unit volume of tissue(Ve),and semi-quantitative parametersthe initial areaunder the enhancement curve(i AUC),using the analysis of variance(ANOVA).And compare various perfusion parameters in colorectal carcinoma between different T staging and differentiation,the difference of the DCE-MRI of each parameter value between the presence of lymph node metastasis and compare the Mann-Whitney Uanalysis,and the parameters of the statistically significant between ROC curve drawing and analysis.Results(1)the quantitative parameter of Ktrans and Kep T staging and differentiation in rectal adenocarcinoma in different degree,the difference had statistical significance between the colorectal carcinoma T2 ~ T4 a Ktrans values respectively(0.379±0.062)min-1,(0.571±0.133)min-1,(0.743±0.111)min-1,Kep value respectively(0.745±0.152)min-1,(1.022±0.170)min-1,(1.294±0.259)min-1,Ve value differences between different T stage has no statistical significance(P> 0.05).High-low differentiation Ktrans values respectively:(0.398 ± 0.055)min-1,(0.522±0.152)min-1,(0.755±0.112)min-1.Kep value respectively:(0.693 ± 0.092)min-1,(0.966±0.166)min-1,(1.302±0.268)min-1,Ve value differences between T stage and differentiation degree has no statistical significance(P> 0.05),value of N0 stage Ktrans,Kep,Ve,respectively(0.434 ± 0.107)min-1,(0.794±0.231)min-1,(0.580 ± 0.140)%,the value of N1 ~ 2 Ktrans,Kep,Ve,respectively(0.646 ± 0.156)min-1,(1.167±0.216)min-1,(0.618 ± 0.184)%,Ktrans value between N0 and N1 ~ 2 difference was statistically significant.Kep and Ve values were not statistically significant between the two.(2)The semi-quantitative parameters i AUC have statistically significant difference between the different stages.The i AUC between differentdegree differentiation and lymph node metastasis in patients with or without lymph node metastasis in patients with differences was no statistical significance.Conclusion DCE-MRI quantitative and semi-quantitative parametersnot only could reflect the T stages and differentiation degree of rectal adenocarcinoma to a certain extent,but also in the aspect of identification with or without lymph node metastasis has a certain value,and Ktrans diagnosis efficiency is higher than i AUC diagnostic efficiency.Therefore,DCE-MRI sequences can be used as complementary sequences of conventional morphological magnetic resonance imaging to provide more information for the selection of individualized treatment options for patients with rectal adenocarcinoma.