Preoperative T and N staging of gastric cancer: magnetic resonance imaging (MRI) versus multi detector computed tomography (MDCT).

BACKGROUND AND AIM: Multi Detector Computed Tomography (MDCT) is widely used in the preoperative staging of gastric cancer. MRI has an emerging role in the evaluation of intestinal diseases, although its role in the staging of gastric cancers is still to be defined. The aim of our study was to compare the diagnostic accuracy of MDCT and Magnetic Resonance Imaging (MRI) in the diagnosis and preoperative staging of gastric cancer, in comparison with histopathology.

MATERIALS AND METHODS: Twenty-five patients with an endoscopic diagnosis of gastric cancer underwent preoperative contrast-enhanced MDCT and MRI, blind to the results of endoscopy. MDCT (64 slices) was performed after oral administration of 800-1000 mL of tap water and scopolamine injection five minutes before the examination. The scan was performed in the axial plane before and after intravenous injection of iodinate contrast medium. Multiplanar reconstruction images were obtained on coronal and sagittal planes. MRI was performed with a 1.5 T Magnet, using the same patient's preparation, by acquiring T2-weighted HASTE sequences, with or without fat saturation (FS), True FISP (True fast imaging with steady state precession) and T1-weighted VIBE (Volumetric interpolated breath-hold examination) sequences, with and without FS, before and after contrast agent (gadolinium) i.v. injection. Gold standards (GS) were surgical and histopathological findings. Two groups of radiologists, blind each other, analyzed MRI images and MDCT findings, and related to GS results.

RESULTS: Detection rate of gastric lesions and T staging for gastric cancer were similar for MRI and MDCT (92%); MRI imaging was superior than MDCT in staging the T parameter (60% versus 48%); the accuracy of MRI imaging and 64-MDCT did not differ significantly in the evaluation of N staging (68% versus 72%).

CONCLUSIONS: Both MRI and MDCT were comparable in staging gastric cancer. MRI was more accurate in evaluation of T stage than MDCT, although both imaging modalities showed low accuracy in detection of early gastric cancer and in differentiation of T2 from T3 stage.