MR Imaging of Advanced Gastric Cancer: Comparison between T1-weighted FLASH, T2-weighted TSE, and TrueFISP

ABSTRACT

PURPOSE: To compare the usefulness of three MR sequences for the depiction and staging of advanced gastriccancer (AGC). MATERIALS AND METHODS: MR imaging was performed in 20 patients in whom AGC was proven by endoscopy.Axial scans with T1-weighted fast low-angle shot (FLASH), T2-weighted turbo spin-echo (TSE), and true fast imagingwith steady state precession (TrueFISP) MR sequences were obtained. We measured the signal-to-noise ratio (S/N) ofgastric cancer and signal difference-to-noise ratio (SD/N) between cancer and intraluminal fluid, cancer and thepancreas, and cancer and perigastric fat in each MR sequence. We also graded lesion conspicuity (poor, fair, orgood), and the degree of serosal invasion in each sequence. All results were correlated with histopathologicfindings. RESULTS: TrueFISP was superior to FLASH or TSE in lesion conspicuity, and showed the highest value ofSD/N between cancer and intraluminal fluid. FLASH showed the highest value of SD/N between cancer and thepancreas, and cancer and perigastric fat. The accuracy of T-staging of AGC with MRI was 75% using FLASH, 70% usingTrueFISP, and 60% using TSE. FLASH sequence understaged in three cases(15%) and overstaged in two (10%). In Usingthe TrueFISP sequence, six cases(30%) were overstaged. CONCLUSION: TrueFISP showed the best lesion conspicuity,but tended to overstage the lesion. T1-weighted FLASH sequence showed the highest value of SD/N on theextraluminal side of the gastric wall, and was better than T2-weighted TSE or TrueFISP for T-staging of AGC.