| Objective:To explore the diagnostic value of Magnetic Resonance Imaging?MRI?in the preoperative staging of gastric cancer,and to analyze the relationship between Apparent Diffusion Coefficient?ADC?,Ki67 expression index and Lauren classification of gastric cancer tissues.The aim is to provide more prognostic information for clinicians to further improve clinical outcomes and better the quality of patients' life.Methods:A retrospective analysis of preoperative MRI and postoperative pathological data from 76 patients with pathologically confirmed gastric cancer from July 2015 to December 2019.The preoperative MRI stage and postoperative pathological stage were compared,and Kappa test was used to observe the consistency of T and N staging between MRI and pathology,and use Chi-square test to evaluate the diagnostic efficacy of different sequences on T staging;meanwhile,applying MR Diffusion post-processing software based on diffusion weighted imaging?DWI?to measure the ADC of gastric cancer tissues.The T-test was used to compare the ADC differences between gastric cancer tissues and normal gastric wall tissues.The ANOVA and SNK test were used to compare the ADC and Ki67 expression index differences of different Lauren types of gastric cancer tissues.The Pearson was used to analyze the correlation between ADC and Ki67 expression index in gastric cancer tissues.Results:1.MRI results in preoperative T-stage of gastric cancer were as follows:1 cases are classified to T1 stage,4 cases are classified to T2 stage,36 cases are classified to T3 stage and 35 cases are classified to T4 stage.The T-stage results of pathological diagnosis were as follows:1 cases were in T1 stage and 10 cases were in T2 stage,26 cases were in T3 stage and 39 cases were in T4 stage.The preoperative T-stage of MRI was compared with the postoperative pathological results:the total accuracy of T is 63.2%?48/76?,the accuracy of T1 is 0.0%?0/1?,the accuracy of T2 is 10.0%?1/10?,the accuracy of T3 is 73.1%?19/26?and the accuracy of T4 is 71.8%?28/39?.Through the consistency test with pathological results,the Kappa coefficients were 0.479?p<0.05?.The T-stage diagnostic accuracy of conventional magnetic resonance imaging?T1WI and T2WI?,conventional scanning combined with DWI,conventional scanning combined with DWI and dynamic contrast enhanced-MRI?DCE-MRI?were 40.8%?31/76?,52.6%?40/76?and 63.2%?48/76?,respectively?p<0.05?.2.The results of MRI on preoperative N-stage of gastric cancer were as follows:15 cases were in N0 stage,31 cases were in N1 stage,14 cases were in N2 stage and 16 cases were in N3 stage.The results of pathological diagnosis of N-stage were as follows:15 cases were in N0 stage,25 cases were in N1 stage,17 cases were in N2 stage and 19 cases were in N3 stage.MRI preoperative staging and postoperative pathological results were compared:the total accuracy of N is 67.1%?51/76?,the accuracy of N0 is 60.0%?9/15?,the accuracy of N1 is 76.0%?19/25?,the accuracy of N2 is 52.9%?9/17?,the accuracy of N3 is 73.7%?14/19?.Through the consistency test with pathological results,the Kappa coefficients were 0.534?p<0.05?.3.The ADC of gastric cancer tissues was?0.92±0.11?×10-3mm2/s,and the normal gastric wall tissue ADC was?1.06±0.09?×10-3mm2/s,the difference was statistically significant?p<0.05?,the area under the ROC curve of ADC determined the normal gastric wall tissue and gastric cancer tissues was 0.807,when the critical value is 0.952×10-3mm2/s,the sensitivity is 61.0%,the specificity is 90.5% and the accuracy is 71.0%.The ADC of intestinal,diffuse and mixed gastric cancer tissues were?1.00±0.07?×10-3mm2/s,?0.84±0.10?×10-3mm2/s and?0.94±0.06?×10-3mm2/s,the ADC of diffuse type was lower than intestinal and mixed type?p<0.05?,the ADC was no significant difference between mixed and intestinal type?p>0.05?;the area under the ROC curve of ADC determined intestinal and diffuse type was 0.891,when the critical value is 0.920×10-3mm2/s,the sensitivity is 76.5%,the specificity is 85.7% and the accuracy is 80.6%.4.The expression index of Ki67 in intestinal,diffuse and mixed gastric cancer tissues was?38.43±12.62?%,?59.12±14.60?% and?50.40±11.00?%,and the diffuse and mixed gastric cancer Ki67 expression index was higher than that of intestinal type?p<0.05?,the Ki67 expression indexes was no significant difference between the diffuse and mixed type?p>0.05?.5.Correlation analysis between Ki67 expression index and ADC value showed that ki67 expression index was negatively correlated with ADC?the r is-0.886?,and ki67 expression index decreased with the increasing of ADC?p<0.05?.Conclusion:MRI can play an important role in the preoperative evaluation of gastric cancer.It has a good consistency in the diagnosis of T and N staging of gastric cancer with pathological results,especially combined with DWI and DCE-MRI,which can improve the accuracy of T staging diagnosis.ADC can be used as a non-invasive prognostic bio-marker for gastric cancer,assisting in the choice of individualized treatment options and prognosis. |
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