Evaluation of the Biliary Tree and Gallbladder With Hepatocellular MR Contrast Agents
ABSTRACT Newer hepatobiliary magnetic resonance (MR) contrast agents allow the ability to combine the anatomical information from T2-weighted magnetic resonance cholangiopancreatography with functional information derived from contrast-enhanced T1-weighted magnetic resonance cholangiography for off-label biliary imaging. Potential applications include determination of biliary anatomy, functional assessment of biliary obstruction, and evaluation for acute cholecystitis. Through MR protocol optimization, it is also possible to achieve this within the standard 30-minute imaging window of liver MR.
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ABSTRACT: Objectives To estimate the additional value of an increased flip angle of 35° in late phase Gd-EOB-DTPA-enhanced magnetic resonance cholangiography, as compared to T2w-MRCP. Methods 40 adult patients underwent Gd-EOB-DTPA enhanced MRI of the liver including a T2-weighted 3D TSE MRCP (T2w-MRCP) as well as a late phase T1-weighted THRIVE sequences applying a flip angle of 35° (fa35). Two experienced observers evaluated the images regarding the delineation of the different biliary regions using a three-point grading system. A five-point scale was applied to determine the readers' confidence in identifying anatomical variations of the biliary tree. ROI analysis was performed to compare the signal-to-noise (SNR) and contrast-to-noise (CNR) ratios. Results The quality for visualizing the biliary tree differed between T2w-MRCP and fa35 (p = <0.001). Late phase EOB-MRC was rated as good for delineating the entire biliary system, whereas T2w-MRCP received an overall poor rating. Especially the depiction of the intrahepatic bile ducts was estimated as problematic in T2w-MRCP. T2w-MRCP and fa35 revealed a discordant assessment of anatomical variations in 12.5% of the cases, comprising a generally higher confidence level for fa35 (4.0 ± 1.1 vs. 2.2 ± 1.2, p = <0.001). SNR proofed to be significantly higher in fa35 (p = <0.001), whereas T2w-MRCP revealed a significantly higher CNR (<0.001). Conclusions Gd-EOB-DTPA enhanced magnetic resonance cholangiography acquired with a flip angle of 35° revealed a better diagnostic performance compared to T2w-MRCP and might be a valuable adjunct in assessing functional bile duct abnormalities.European Journal of Radiology 10/2014; 83(10). DOI:10.1016/j.ejrad.2014.06.005 · 2.16 Impact Factor