Determination of cystic duct patency using hepatobiliary MRI with gadoxetate disodium: Is T1 precontrast imaging necessary?

Abstract

To determine the need for precontrast T1-weighted imaging in determining cystic duct patency using hepatobiliary phase imaging with gadoxetate disodium-enhanced magnetic resonance imaging (MRI). MRI exams using gadoxetate disodium from October 4, 2008 to April 14, 2010 were reviewed in a retrospective fashion. Two reviewers independently reviewed only the 20-minute T1-weighted delayed postcontrast images to determine the presence of excreted contrast in the gallbladder lumen. Contrast was deemed present if hyperintense signal material was seen in the antidependent portion of the gallbladder lumen. The actual presence of contrast in the gallbladder was determined by directly comparing the pre- and postcontrast T1-weighted images using consensus review. In all, 187 cases were included. Three (1.6%) were deemed indeterminate due to complete homogeneous opacification of the gallbladder. All three cases were identified as indeterminate by both reviewers. Of the remaining 184 cases, 136 filled (74%) and 48 did not fill (26%). Both reviewers correctly identified 136/136 cases of gallbladder filling. Reviewer A identified 47/48 cases of nonfilling and reviewer B identified 46/48 cases of nonfilling. Sensitivity and specificity were 100% and 98% for reviewer A and 100% and 96% for reviewer B, respectively. The presence of excreted contrast in the gallbladder lumen can be determined using gadoxetate disodium-enhanced MRI without precontrast T1-weighted imaging.