MR imaging of advanced gastric cancer: comparison of various MR pulse sequences using water and gadopentetate dimeglumine as oral contrast agents

Background: To evaluate clinical usefulness of oral contrast agents (gadope ntetate dimeglumine and water) and to assess proper magnetic resonance (MR) imaging in evaluating advanced gastric cancer (ACC) by comparing different MR imaging techniques. Methods: Fifteen patients with AGC were imaged with a 1.0-T MR imager and b ody-array coil. All patients underwent surgery or laparascopic biopsy. Fast low-angle shot (FLASH), half-Fourier single-shot turbo spin-echo (HASTE), and true fast imaging with steady-state precession time (FISP) images were obtained after ingestion of 900 mL tap water in each patient, followed by p ostcontrast FLASH images after additional ingestion of gadopentetate dimegl umine (Gd-DTPA). Qualitative analysis including T-staging of AGC and scorin g of imaging quality and quantitative analysis were performed prospectively . Results: In image quality and diagnostic accuracy of T-staging, FLASH imagi ng showed results slightly superior to those of other imaging modalities, a nd there was no great difference between using water and Gd-DTPA as an oral contrast agent. As for cancer-to-gastric lumen contrast-to-noise ratio (CN R), HASTE and true FISP imaging were superior to FLASH imaging with Gd-DTPA (p < 0.0001). In cancer-to-pancreas CNR, FLASH imaging without Gd-DTPA sho wed the best result. Conclusions: The use of Gd-DTPA as a positive contrast agent may not be imp erative, and T1-weighted FLASH imaging in combination with true FISP imagin g with ingestion of tap water can be very useful in evaluating AGC with MR imaging.