Application of Magnetic Resonance Images in Gastrointestinal Malignancies

Thirty three patients, who were previously documented to have gastric, duodenal or colorectal malignancies by endoscopy and biopsy, underwent magnetic resonance imaging (MRI) to evaluate the clinical usefulness of MRI on assessing depth of invasion, regional lymphadenopathy and hepatic metastasis. Most of these patients had undergone either barium or computed tomgraphy (CT) studies within one week before the MR imaging. The MRI, CT, and operative findings including tumor extension, extraserosal invasion, regional lymph nodes and regional or distant metastases were compared. The results showed that MRI provided advantages over CT for determining local invasion because of high tissue contrast and multiplanar imaging capacity. In addition, MRI provided high quality images in the patient with gastric outlet or colonic obstruction that the retained barium might prohibit subsequent CT scan. In such situations, barium studies only showed the obstruction; however, the lesion would be better depicted by MRI. Furthermore, MRI was comparable to CT in showing regional lymphadenopathy and hepatic metastasis. As a result, it is suggested that MRI has the potential to replace the combination of barium study and CT for preoperative staging of gastrointestinal malignancies in the situation when the latters may not be performed optimally.