Rationale and objectives: The authors performed this study to quantitate the change in intrabiliary signal intensity 20 minutes after gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid (Gd-EOB-DTPA) injection and to correlate the degree of biliary visualization with changes in biliary signal intensity.
Materials and methods: Sixteen patients with known hepatic masses (without known biliary disease) who were candidates for resection were enrolled in an open-label protocol of Gd-EOB-DTPA. Three-dimensional spoiled gradient-echo magnetic resonance (MR) images obtained in the coronal plane with breath holding before and 20 minutes after Gd-EOB-DTPA made up the biliary MR cholangiogram study. Manually defined regions of interest were used to measure signal intensity in the bile ducts before and after contrast material administration. Signal-to-noise ratios (SNRs) and contrast-to-noise ratios (CNRs) were calculated. Biliary visualization was qualitatively assessed by using a five-point scale.
Results: The SNR and CNR significantly increased (P < .0002) after the administration of contrast material. Average biliary visualization ratings were excellent, with moderate to excellent interobserver agreement. There was no correlation between measured SNR or CNR and visualization ratings.
Conclusion: A 20-minute delay after Gd-EOB-DTPA administration appears to be sufficient for adequate biliary enhancement. Residual hepatic enhancement does not appear to interfere with biliary visualization.