3.0T MRI Diffusion Weighted Imaging Sequences Compare And Correlation Of Apparent Diffusion Coefficient Value With The Histological Differentiation In Gastric Cancer

Objective To evaluate the qualitative image quality of three diffusion weighted imaging sequences in 3.0T MRI;To evaluate the correlations between histological differentiation of gastric cancer and the apparent diffusion coefficient(ADC)value,and to evaluate the ability of diffusion weighted imaging(DWI)sequence in predicting the malignant degree of gastric cancer.Subjects and Methods Two hundred and thirty-five patients(166 males,69females;mean age,62.5±9.5 years)with gastric cancer were collected,who underwent magnetic resonance(MR)scans at 3.0 T,including conventional diffusion weighted imaging(DWI),reduced FOV DWI(r FOV DWI)and integrated slice-by-slice shimming DWI(i Shim DWI).Two observers subjectively evaluated image quality for conventional DWI,r FOV DWI and i Shim DWI sequences regarding the anatomic details,distortion,lesion conspicuity,artifacts,and overall image quality.An ADC map containing the largest slice of the tumor was adopted,in which Mean ADC values were were calculated for each gastric cancer by two obser-vers.Mean ADC values of gastric cancers with different degrees of differentiation were compared,and the diagnostic performance of the three sets of DWI were evaluated.The Dunnett-t test,paired samples t test,chi-square test and receiver operating characteristic(ROC)curve were used.Results the qualitative image analysis demonstrated significant differences in image quality in terms of anatomic details,distortion,lesion conspicuity,artifacts and overall image quality between conventional DWI and the other two DWI sequences(r FOV DWI and i Shim DWI);i Shim DWI yielded significantly better scores in image quality in terms of lesion conspicuity and overall image quality than r FOV DWI,but there were no significant differences in image quality in terms of anatomic details,distortion,and artifacts.In the quantitative analysis,the patients were divided into moderately differentiated group(n = 25),poorly differentiated group(n = 37)and low adhesive carcinoma(n = 19),according to the degrees of differentiation.The univariate analysis showed that the ADC values in the degrees of differentiation had no correlations with gender,tumor site,intensive modalities,age and tumor long dia-meter(P > 0.05,respectively).However the degrees of differentiation showed sig-nificant differences with conventional ADC,r FOV ADC and i Shim ADC.The area under curve(AUC),sensitivity,specificity and accuracy of The i Shim DWI was 0.829,96%,55.4%,81.5% respec-tively,which behaved as the better diagnostic threshold than the conventional DWI and r FOV DWI.Conclusion Among the three DWI,r FOV DWI and i Shim DWI had better image quality.Whereas,the image qualityi of shim DWI was superior to r FOV DWI.ADC value was associated with the histological differentiation of gastric cancer,and the i Shim ADC had the highest diagnostic efficiency and higher accuracy for moderately differentiated gastric adenocarci-noma(compared with conventional ADC),which is expected to improve the clinical value of ADC as a noninvasive biological index to help judge the histological differentiation of gastric cancer.