| Objective:To analyze the value of apparent diffusion coefficient?ADC?and relative apparent diffusion coefficient?rADC?of 1.5T magnetic resonance diffusion weighted imaging for the diagnosis of primary rectal cancer,pathological grade and T stage,and to compare the difference of ADC value of gluteus maximus and obturator internus in all patients,as well as the diagnostic efficacy of rADC value of gluteus maximus and obturator internus as reference sites for poorly differentiated rectal cancer.Materials and methods:The MRI datum of 83 cases of biopsy-pathologically confirmed rectal cancer suffers after operation?47 males and 36 famales?were collected retroactively,from July 2017 to July 2019,in China-Japan Union Hospital of Jilin University.All patients involved in the study were examined by MRI within two weeks before the operation.Conventional sagittal,axial and coronal T2WI sequences and axial T1WI sequences,cross-sectional high-resolution T2WI and DWI scans corresponding to axial T2WI were uplined at 1.5TMRI.Analysis of routine MRI and DWI imaging characteristics:?1?ADC values in the region ofinterest?ROI?of the lesion were first measured,and then compared with different normal reference tissues to calculate the relative ADC values?rADC?.The reference tissue was selected as the right gluteus maximus at the same level as the lesion and the obturator internus muscle at the right maximum diameter.To compare the ADC values of gluteus maximus and obturator internus between 83 patients with rectal cancer of different ages and genders.?2?To analyze the differences of ADC,rADCgluteus maximus and rADCobturator internus in different pathological grades of rectal cancer and the correlation between them and the differentiation degree of rectal cancer.?3?To analyze the value of ADC,rADCgluteus maximus and rADCobturator internus in the differential diagnosis of low-differentiated rectal cancer and to compare the difference of the area under the curve?AUC?among the three.?4?To compare the correlation between different T stages of rectal cancer and ADC value,rADCgluteus maximus value and rADCobturator internusbturator internus value.SPSS 22.0 and stata 13.0 software were used for statistical analysis of the obtained data.When the measurement data was normally distributed,ADC value was expressed by mean plus or minus standard deviation.The independent samples t test was used between the two groups.When the comparison data in the group were consistent with homogeneity of variance,one-way ANOVA was used to test the difference hypothesis of the three groups and above.When P<0.05,the LSD test was for pairwise comparison between groups.Non-normal distribution data were represented by median and quartile spacing,and intra-group differences were compared by non-parametric test.The sensitivity and specificity of ADC value,rADCgluteus maximus value and rADCobturator internal value in the prediction of low-differentiation rectal cancer were calculated using the ROC curve,and the differences in area under the curve were compared.ADC values measured by two radiologists were tested for consistency.P<0.05 was used as the statistically significant standard in this study.Results:?1?There was no significant difference in ADC values between the gluteus maximus and obturator internus among 83 patients with rectal cancer of different ages and genders?p>0.05?.The mean ADC values of the gluteus maximus and obturator internus were 1.43±0.11 x10-3mm2/s,and 1.34±0.10x10-3mm2/s.?2?Among the 83 patients with rectal cancer,there were 9 patients in the highly differentiated group,54 in the moderately differentiated group,and 20 in the poorly differentiated group.In the highly differentiated group,the value of the ADC,rADCgluteus maximus,and rADCobturator internus were 1.17±0.17 x10-3mm2/s,0.86±0.13,and 0.89±0.15,respectively,in the moderately differentiated group,the value of the ADC,rADCgluteus maximus,and rADCobturator internus were 0.85±0.12 x10-3mm2/s,0.60±0.10,and 0.63±0.10,respectively.In the low-differentiation group,the values of the ADC,rADCgluteus maximus and rADCobturator internus were 0.73±0.09 x10-3mm2/s,0.49±0.06 and 0.56±0.07,respectively.The values of ADC,rADCgluteus maximusluteus maximus and rADCobturator internus rectal cancer were negatively correlated with the degree of differentiation,with correlation coefficients of-0.622,-0.670 and-0.564,respectively,p<0.01.?3?The ROC curves of ADC,rADCgluteus maximusluteus maximus and rADCobturator internus values were plotted with low differentiation as the test values of variables.The sensitivity,specificity and AUC of the three indexes were ADC:80.0%,77.8%and0.815;rADCgluteus maximus:85.0%,80.9%,0.855;rADCobturator internus:65.0%,79.4%,0.766.The difference of area under the three curves was statistically significant?P<0.05?.The AUC of the three indicators is greater than 0.700.Therefore,it can be inferred that the above indicators have certain differential diagnosis efficacy for low-differentiated rectal cancer.?4?ADC values of T1-T4 stage in 85 patients with rectal cancer were 1.01?0.20?x10-3mm2/s,0.88?0.18?x10-3mm2/s,0.81?0.14?x10-3mm2/s,0.73?0.11?x10-3mm2/s,respectively.The rADCgluteus maximusluteus maximus values of T1-T4 stage were 0.73±0.18,0.61±0.12,0.58±0.11,and 0.45±0.04,respectively.The rADCobturator internus val ue T1-T4 stage was 0.69?0.34?,0.64?0.19?,0.61?0.11?,0.57?0.10?,respectively.Spearman correlation analysis showed that the mean ADC,rADCgluteus maximusluteus maximus an d rADCobturator internusbturator internus values of the lesion were negatively correlated with the T stage,and the correlation coefficients were?r=-0.396,-0.436,-0.369,P<0.01?.Conclusion:The values of ADC,rADCgluteus maximus and rADCobturator internus are all helpful in the differential diagnosis of poorly differentiated rectal cancer.Among them,rADC gluteus maximus value has a higher diagnostic efficiency,and the three were negatively correlated with the differentiation degree and T stage of rectal cancer. |
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