High Spatial Resolution T1-Weighted MR Imaging of Liver and Biliary Tract During Uptake Phase of a Hepatocyte-Specific Contrast Medium

Abstract

The hypothesis for this prospective study was that T1-weighted respiratory triggered high spatial resolution images of the liver acquired during the uptake phase of a hepatobiliary contrast medium are technically feasible and provide significantly improved image quality compared with breath-hold images. An inversion recovery-prepared spoiled gradient echo sequence was developed that can be obtained with respiratory triggering. This sequence was acquired in 20 patients with a total of 41 focal liver lesions and compared with axial and coronal breath-hold spoiled gradient echo sequences. All 3 sequences were obtained in the hepatobiliary phase after intravenous injection of Gd-EOB-DTPA at a dosage of 0.025 mmol/kg of body weight. Quantitative evaluation measured the contour sharpness index of the common bile duct and calculated the relative contrast between liver lesions (common bile duct, respectively) and liver parenchyma. In the qualitative assessment, 2 readers independently scored the depiction of focal liver lesions and 3 segments of the biliary tract, the sharpness of hepatic vessels, and the level of artifacts. Statistical significance was assumed at P < 0.05. The respiratory-triggered sequence was technically successful in all 20 patients, revealed significantly higher liver-lesion contrast, contour-sharpness index and scores for depiction of focal liver lesions, biliary tree, and sharpness of hepatic vessels compared with the respective breath-hold sequence. The relative contrast between the common bile duct and the liver parenchyma was significantly higher for the coronal breath-hold sequence compared with the respiratory-triggered sequence. No significant difference was found with respect to the level of artifacts. The 2 readers agreed in 77.9% of the qualitative assessments. T1-weighted respiratory triggered high spatial resolution images obtained in the hepatobiliary phase are technically feasible and significantly improve the image quality compared with breath-hold images.