Intraindividual Crossover Comparison of Gadoxetic Acid Dose for Liver MRI in Normal Volunteers

抄録

Purpose: We performed a quantitative intraindividual comparison of the performance of 0.025- and 0.05-mmol/kg doses for gadoxetic acid-enhanced liver magnetic resonance (MR) imaging.
Materials and Methods: Eleven healthy volunteers underwent liver MR imaging twice, once with a 0.025- and once with a 0.05-mmol/kg dose of gadoxetic acid. MR spectroscopy and 3-dimensional gradient-echo T₁-weighted images (3D-GRE) were obtained before and 3, 10, and 20 min after injection of the contrast medium to measure T₁ and T₂ values and signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) performance. During the dynamic phase, highly time-resolved 3D-GRE was used to estimate the relative CNR (CNR_rel) of the hepatic artery and portal vein (PV) to the liver. We used paired t-tests to compare the results of different doses.
Results: During the hepatobiliary phase, we observed shorter T₁ values and higher SNRs of the liver (P < 0.001) and higher liver-to-PV and liver-to-muscle CNRs (P < 0.002) using 0.05 mmol/kg compared to 0.025 mmol/kg. Increasing the dose to 0.05 mmol/kg yielded a greater T₁-shortening effect at 10 min delay even compared with 0.025 mmol/kg at 20 min (P < 0.001). During the dynamic phase, the peak CNR_rel for the hepatic artery and portal vein were higher using 0.05 mmol/kg (P = 0.007 to 0.035).
Conclusion: Use of gadoxetic acid at a dose of 0.05 mmol/kg leads to significantly higher SNR and CNR performance than with 0.025 mmol/kg. Quantitatively, a 10-min delay may be feasible for hepatobiliary-phase imaging when using 0.05 mmol/kg of gadoxetic acid.