Diffusion-weighted magnetic resonance imaging in the depiction of gastric cancer: initial experience

The aim of the study was to explore the feasibility of diffusion-weighted magnetic resonance imaging (DW-MRI) in the depiction of gastric cancer and to investigate the signal characteristics and apparent diffusion coefficient (ADC) of gastric cancer. An institutional review board-approved protocol was developed for this prospective study. DW-MRI was performed on 101 patients with gastric cancer that was detected by gastroscopy biopsy. The optimal number of excitations (NEX) for DW-MRI was determined, and the signal characteristics of gastric cancer on DW-MRI were analyzed. The ADC of gastric cancer was measured by two experienced radiologists independently, and the reproducibility of measurement was investigated by the Bland-Altman analysis. When DW-MRI was used with four NEXs, areas of gastric cancer showed a good contrast and contrast-to-noise ratio. Four kinds of signal characteristics of gastric cancer were observed on DW-MRI: uniformly high signal, inner high signal, and outer low signal (two-layer type), high-low- high signal (three-layer sandwich type), and mixed type. The mean ADC of gastric cancer measured by two observers was (1.18 +/- 0.29) 9 10(-3) mm(2)/s and (1.20 +/- 0.31) x 10(-3) mm(2)/s respectively, which showed good agreement with Bland-Altman analysis (95% limits of agreement: -0.16 to +0.19 x 10(-3) mm(2)/s). Gastric cancers have various signal characteristics on DW-MRI and the reproducibility of ADC measurement is satisfactory. DW-MRI is helpful in the depiction of gastric cancer.