3D MR Colonography after exclusive intravenous administration of a hepatobiliary contrast agent

Introduction Cross-sectional imaging of the colon has been recently introduced as MR or CT colonography. All methods rely on the aboral or oral administration of a contrast agent, which does change the physiological function of the colon. While performing several clinical studies using a partially hepatobiliary excreted contrast agent, we noted substantial intraluminal colonic contrast 24 hrs post injection. Subsequently, we investigated the potential of exclusive contrasting the colon via a hepatobiliary excreted MR contrast agent for 3D MR colonography. Methods Six volunteers were enrolled in a MR angiographic study of the abdominal vasculature with gadobenate dimeglumine at 0.1 mmol/kg body weight. The volunteers were studied according to an angiographic protocol approved by the IRB and performed according to GCP. Prior written informed consent was obtained from each volunteer. Gadobenate Dimeglumine (Gd-BOPTA, Multihance, Bracco Diagnostics, Princeton, NJ) exhibits a partial hepatobiliary excretion (reported 2 4 %). Follow-up imaging using a 3D MR angiographic-(MRA) sequence (3D FLASH; TR 4.6 ms; TE 1.8 ms; a 50°; rect. FOV 390 mm (6/8); Ma: 215x512; acquisition time: 28 s; slab thickness: 120 mm; 42 partitions) was carried out at 1, 12, 24, 36, 48, 70, and 105 h post injection in all subjects. In addition to the 3D MRA-sequence, T1-weighted axial images of the liver and abdomen were obtained. The subjects were instructed to document their dietary patterns. No contrast enema nor any medication was given. All imaging was performed on a 1.5 T MRI scanner equipped with a phased array body coil. Post-processing was performed on the system work station using standard MIP software.