Feasibility study of using air as a contrast medium in MR colonography

AIM: To evaluate the feasibility of using air as intraluminal contrast medium in magnetic resonance (MR) colonography. MATERIALS AND METHODS: Twenty-two patients underwent MR colonography (MRC) using air before colonoscopy. All patients were imaged in prone and supine positions. Each colon was divided into five segments. Two radiologists reviewed the images for the degree of colonic distension, image quality and colonic lesions. The colonic lesions identified using MR were compared with those identified on colonoscopy. RESULTS: Eight men and 14 women with mean age of 55.5 years were studied. All patients completed the MR examination. One hundred and five out of 110 (95.5%) colonic segments were well distended in both prone and supine positions. Image quality was good in all cases. Colonoscopy detected 16 lesions: three greater than or equal to1 cm, one 7 mm lesion and 12 lesions less than or equal to5 mm. All lesions 1 cm or larger were detected by MRC. CONCLUSION: MRC using air and the single-shot half-Fourier rapid acquisition with refocused echos (RARE) technique is feasible. But in this small pilot study, it had low sensitivity for the detection of polyps less than 1 cm in diameter. (C) 2003 The Royal College of Radiologists. Published by Elsevier Science Ltd. All rights reserved.