MR imaging of the gastrointestinal tract with i.v., gadolinium and diluted barium oral contrast media compared with unenhanced MR imaging and CT

Abstract

Objective: To determine an optimal MR imaging technique and pulse sequence for evaluating mural and serosal disease of the gastrointestinal tract, we administered 2% oral barium sulfate and obtained fat-suppressed gadolinium-enhanced breath-hold fast multiplanar spoiled gradient-recalled (FMPSPGR) MR images. We then compared these images with spin-echo T1-weighted and T2-weighted fast spin-echo MR images and with CT images.

Subjects and methods: Thirty-one patients with suspected diseases of the gastrointestinal tract were imaged with spin-echo T1-weighted, fast spin-echo T2-weighted, and fat-saturated gadolinium-enhanced FMPSPGR MR imaging. Before undergoing MR imaging, all patients received 1350 ml of 2% barium sulfate oral contrast media. For CT scans, patients received 120 ml of iodinated i.v. contrast material and 2% barium sulfate oral contrast material. CT and MR images were retrospectively and independently reviewed by two radiologists for ability to see normal bowel wall, for the presence of abnormal gastrointestinal tract mural thickening or enhancement, and for overall gastrointestinal tract visualization. Findings were correlated with surgical findings, endoscopy, and barium studies.

Results: Ten patients had benign disease, 16 had malignant gastrointestinal tract disease, and five had no gastrointestinal tract abnormalities. In 94% of patients, the gadolinium- and barium-enhanced FMPSPGR MR images were superior to CT and spin-echo MR sequences for depicting the wall of the normal bowel (p < .001). For the two observers, the FMPSPGR MR images with i.v. and oral contrast material were seen as revealing 94% and 95% of bowel segments with malignant or inflammatory mural thickening or serosal tumor. In comparison, CT revealed 64% and 72% (p < .01 and p < .0001, respectively), fast spin-echo T2-weighted MR images revealed 21% and 28% (p < .0001), and T1-weighted MR images revealed 17% and 18% (p < .0001). The gadolinium- and barium-enhanced MR images were preferred for overall gastrointestinal tract visualization in 65% of patients compared with 1% for CT scans (p < .001). In 32% of patients, the enhanced MR images were equivalent to CT images.

Conclusion: MR evaluation of the gastrointestinal tract requires bowel distention with oral contrast material as well as motion reduction techniques, including glucagon and rapid gradient-echo pulses that allow breath-hold imaging. Fat-suppressed gadolinium-enhanced FMPSPGR MR imaging with diluted barium oral contrast media is effective for imaging benign and malignant mural and serosal abnormalities of the gastrointestinal tract.