Diffusion-weighted magnetic resonance imaging in evaluation of gastric cancer.

OBJECTIVE To investigate the role of diffusion-weighted magnetic resonance imaging (DW-MRI) in the diagnosis of gastric tumors and discuss the diagnostic importance and potential use of apparent diffusion coefficient (ADC) measurements. MATERIALS AND METHODS Beginning in March 2009, DW-MRI was added to the routine abdominal and pelvic MR examination for all patients imaged at our institution. A total of 21 patients (12 men and 9 women; mean age 55±6.3SD, range: 39-74 years) with known gastric malignancy were referred to our MR unit. All MRI examinations were performed using a 1.5-T MRI scanner (Magnetom Avanto, Siemens Healthcare). The evaluation of the DW-MRI examinations was made by radiologists' consensus. Changes in the signal intensity of the lesions were determined by their appearance in images at b=50, 400, and 800 s/mm(2) and in ADC maps. Results were compared with histopathological findings. RESULTS All of the gastric tumors in this study showed high signal intensity in DW-MRI and low signal intensity in ADC maps. Mean ADC values for gastric tumor and normal gastric wall were 0.892±0.23 SD mm(2)/s and 1.453±0.35 SD mm(2)/s respectively. The mean ADC values of gastric tumors were significantly lower than that of the normal gastric wall. CONCLUSION DW-MRI and ADC values together can successfully differentiate gastric tumors from normal gastric wall.