VEGETABLE OIL AS AN MR CONTRAST AGENT FOR RECTAL APPLICATIONS

The purpose of the study was to evaluate the feasibility of pure veget able oil as an MR contrast agent for rectal applications. The hypothes is was that vegetable oil highlights the lumen of the rectum after rec tal application as a positive contrast medium and offers additional co ntrast qualities using fat suppression techniques. Eleven MRI examinat ions were performed on 11 subjects (five healthy volunteers, all males , mean age 35 yr; and six patients, three males, three females, mean a ge 49 yr). Peanut oil, 200 mi, was applied rectally. In addition, 0.1 mmol/kg GD-DTPA was administered intravenously to the six patients onl y. Conventional T-1-weighted SE sequences and and T-1-weighted SE imag es with fat suppression were obtained. Criteria for image evaluation w ere: overall image quality; uniformity of contrast distribution; chemi cal shift artifact; and delineation of the rectal wall. Side effects w ere assessed. There were no complaints reported by the 11 subjects. Th e image quality was sufficient in all studies. In all five of the volu nteers and five of the six patients, the distribution of oil was unifo rm. Chemical shift artifacts did not deteriorate image quality. After rectal application of vegetable oil, the delineation of the rectal wal l was sufficient with and without fat suppression techniques. Vegetabl e oil highlights the lumen of the rectum in MRI studies and offers add itional contrast qualities with fat suppression techniques, acting as a positive as well as a negative contrast agent, depending on the chos en sequence.