Vascular Enhancement in Early Dynamic Liver MR Imaging in an Animal Model: Comparison of Two Injection Regimen and Two Different Doses Gd-EOB-DTPA (Gadoxetic Acid) With Standard Gd-DTPA

Objectives: To investigate the influence of 2 different closes and injection rates oil the enhancement of liver vasculature in Gd-EOB-DTPA enhanced liver MRI compared with the standard dose Gd-DTPA. Materials and Methods: This animal experimental study has been approved by the local authorities. In 5 pigs, a time-resolved T1w 3D GRE sequence, and in a second experiment, a single-slice turbo FLASH T1w sequence with 3 frames/s were started each with contrast agent application of Gd-EOB-DTPA trod Gd-DTPA. Three sets with different doses were performed with an injection rate of 1 and 2 mL/s which are as follows: A, Standard dose: 25 mu mol Gd-EOB-DTPA/kg body-weight (bw); B, Double dose: 50 mu mol Gd-EOB-DTPA/kg bw: and C, Standard dose: 100 mu mol Gd-DTPA/kg bw. Signal intensities were measured in aorta, vena cava inferior, portal vein, and liver parenchyma, and time-signal-to-noise (SNR)-curves were generated. The increase in SNR from baseline and several perfusion parameters were calculated. Statistical significance was tested with the Wilcoxon rank test at a significance level of P = 0.05. Results: Mean peak enhancement (SNR) in the aorta was 'not significantly different for set A, B, and C with the wine injection rate. Mean peak enhancement in the aorta was significantly higher for set A at 1 mL/s than at 2 mL/s (159.1 vs. 144.4, P = 0.043). Mean peak enhancement in the PV. the vena cava inferior, and the liver parenchyma was significantly lower for set A compared with set B and set C, at both injection speeds. The full width at half max was significantly longer for injection protocols with 1 as compared with 2 mL/s for sets A and set B. Set A with 1 mL/s reached similar values as compared with set C with 2 mL/s for the full width at half alas (8.92 vs. 9.40; P = 0.35), for the area-under-the curve (1736.64 vs. 1912.74: P = 0.69) and the maximal signal-to-noise ratio (25.21 vs. 25.37; P = 0.69). Conclusion: Despite the lower amount of gadolinium ill the standard close of Gd-EOB-DTPA, the results showed that the arterial enhancement in Gd-EOB-DTPA-enhanced dynamic liver MRI was comparable to Gd-DTPA. This result can be explained mainly by the higher relaxivity. Choosing a lower injection rate additionally supported to compensate for the lower injection volume by stretching the bolus without decreasing the peak. fit this respect, an injection rate of 1 mL/s showed better results with regard to the arterial enhancement compared with 2 mL/s.