Preoperative apparent diffusion coefficient value of gastric cancer by diffusion‐weighted imaging: Correlations with postoperative TNM staging

Background To determine if the apparent diffusion coefficient (ADC) values of gastric cancers on the preoperative diffusion weighted imaging (DWI) correlate with the postoperative TNMs of the lesions. Methods In a retrospective clinical study, seventy patients with gastric cancers were enrolled and each underwent a MRI before surgery. DWI was obtained with a single‐shot, echo‐planar imaging sequence in the axial plane (b values: 0 and 1000 s/mm 2 ). The mean and minimum ADC values of the gastric cancers were calculated and compared among various postoperative TNM staging. Results Both mean and minimum ADC values of the gastric cancers correlated with the postoperative T staging (r = −0.464, −0.476; both P < 0.001), N staging (r = −0.402, −0.397; P = 0.001, 0.002) and TNM staging (r = −0.446, −0.437; both P < 0.001). The areas under the receiver operating characteristic (ROC) curves for the differentiating lymph node metastasis were 0.788 for the mean ADC values ( P = 0.001) and 0.778 for the minimum ADC values ( P = 0.001). Conclusion The preoperative ADC values of gastric cancers can help to assess the postoperative TNM staging. J. Magn. Reson. Imaging 2015;42:837–843.