Purpose: To correlate the role of MRI in staging gastric carcinoma in comparison with high resolution multidetector-row spiral CT.
Methods and Materials: 35 patients with gastric carcinoma underwent preoperative MRI and multislice CT of the abdomen, after drug induced hypotonia and water filling. MRI was performed at 1.5 Tesla using FLASH fat suppressed and non fat suppressed, pre and post Gadolinium enhancement (TR/TE/acq.time:140 msec/5,3 msec/20 sec; thick: 6mm; 0,10mm gap); HASTE (TR infinite/TE 90 msec, ETL 104, thickness 6mm, 0,10mm gap, FOV 350-400, matrix 192x256, acq.time:20 sec) and true-FISP (TR/TE/acq.time:4,8 msec/2,3msec/14 sec; thick:5mm) sequences. Post gadolinium images were acquired in the arterial, portal and late phase. Precontrast multislice CT was acquired at the level of the upper abdomen with 5 mm slice thickness (2.5mm collimation, 5mm reconstruction interval); after i.v. administration of 150 ml of iodinated contrast media at 4 ml/s, arterial (30 sec delay) and venous (60 sec delay) phases were acquired at 1.25 of slice thickness (1mm collimation; 1mm reconstruction interval). The pelvis was then scanned with 5mm thickness (2.5mm collimation, 5mm reconstruction interval). All images were analyzed with multiplanar reconstructions.
Results: The detection rate of early gastric cancer (ECG) was 80% (4/5) for CT and 60% (3/5) for MRI; the detection rate of advanced gastric cancer (AGC) was 100% (30/30) for both modalities. Regarding the T stage, in 25/35 (71.4%) for CT and 27/35 (77.1%) for MRI there was a good correlation with histological results. Regarding the N stage a good correlation with pathologic results occurred in 26/35 (74.2%) for CT and in 20/35 (57.1%) for MRI. Regarding the M factor CT was concordant with surgical and pathological findings in 32/35 patients (91.4%), MRI in 33/35 (94.2%).
Conclusion: T and M staging of gastric cancer with current MRI techniques is comparable with multislice CT. MRI is suboptimal for the N staging and further improvements are necessary.