| Objective:To investigate the value of intravoxel incoherent motion?IVIM?in preoperative evaluation of rectal adenocarcinoma.Methods:A total of 54 patients with rectal adenocarcinoma who planned to undergo radical surgery at Shengjing Hospital without anti-tumor treatment such as radiotherapy and chemotherapy were enrolled.All patients underwent routine rectal 3.0T MRI scan within 1 week before surgery,including T2WI Axial,Coronal,Sagittal imaging and axial IVIM sequences,including 10 different b values 0,10,20,50,100,200,400,600,800,1000s/mm2,patients with pre-scanning fasting 4-6 hours and Clean the intestines.Extract the original images of the IVIM sequence and import it into the IVIM post-processing software,select the appropriate ROI,and perform image processing analysis to obtain quantitative parameters:standard apparent diffusion coefficient?ADC?value,simple diffusion coefficient?D?,perfusion-related diffusion coefficient?D*?.And perfusion score?f?.The ROI was selected in the largest section of the solid part of the tumors.The shape of the ROI was manually selected according to the shape of the lesion.Take care to avoid the cystic,necrotic area and the contents of the intestine.The measurements were made 3 times at different times and finally averaged.The T stage of rectal adenocarcinoma was divided into T1,T2,T3,and T4 according to the 8th edition of the tumor staging standard developed by the American Joint Committee on Cancer?AJCC?,followed by 3 cases,12 cases,36 cases,and 3 cases.According to whether the tumor breaks through the muscularis propria,the tumor is divided into the non-breaking muscular group?including 15 cases in T1 and T2?and the breakthrough muscular layer?including 39 cases in T3 and T4?.According to the postoperative pathological results,the tumors were divided into three groups:high,medium and low differentiation,15 cases,32 cases and 7 cases respectively.The comparison of IVIM quantitative parameters during different T-stage of rectal adenocarcinoma?two groups?was tested by independent sample t test.For the comparison of IVIM quantitative parameters between different degrees of differentiation of rectal adenocarcinoma?high,medium and low differentiation?,one-way analysis of variance?data satisfies the normal distribution?;if the data does not satisfy the normal distribution,a nonparametric test were used.Spearman correlation analysis was used to explore the correlation between IVIM related parameters and degree of differentiation.P<0.05 was statistically significant.Results:The ADC and f values of the non-breaking muscular group?T1,T2?were?1.026±0.070?×10-33 mm2/s,?0.358±0.038?.The ADC and f values of the broke through the muscularislayer?T3,T4?group were?0.959±0.111?×10-33 mm2/s and?0.283±0.034?.There was a statistically significant difference in ADC and f between the two groups?P<0.05?.The D and D*values of the non-breaking muscular group were?0.959±0.119?×10-33 mm2/s,?9.980±1.671?×10-33 mm2/s,respectively;The D,D*value of the broke through the muscularislayer?T3,T4?group is?0.909±0.111?×10-33 mm2/s,?9.706±1.166?×10-33 mm2/s.There were no significant differences in D andD*values between the two groups?P>0.05?.The ADC values of the low,medium and highdifferentiation groups were?0.799±0.105?×10-33 mm2/s,?0.978±0.066?×10-33 mm2/s,?1.063±0.059?×10-33 mm2/s.The values of D are?0.797±0.074?×10-33 mm2/s,?0.890±0.076?×10-33 mm2/s,?1.050±0.081?×10-33 mm2/s.The ADC and D values increased gradually with the increase of tumor differentiation degrees,and the difference between the two groups was statistically significant?P<0.05?.The ADC and D values werehighly positively correlated with the degree of differentiation(rADC=0.676,P<0.05),?rD=0.722,P<0.05?.The D*values of low,medium,high differentiation group were?9.570±1.246?×10-33 mm2/s,?9.644±1.526?×10-33 mm2/s,?10.175±0.698?×10-33 mm2/s,respectively;f values of the low,medium,and high differentiation groups were?0.269±0.020?,?0.305±0.050?,?0.317±0.049?,respectively.There was no significant difference in D*and f values between the three groups?P>0.05?.Conclusions:The ADC and f values help to identify the breakthrough muscularis propria group and the unbroke muscular group;ADC and D values are highly positively correlated with the differentiation of rectal adenocarcinoma,which is helpful for preoperative evaluation of the differentiation of rectal adenocarcinoma.IVIM has a certain value in the evaluation of preoperative T stage and differentiation of rectal adenocarcinoma,which can provide valuable information for treatment options and prognosis evaluation. |
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