Study Of Delay Time Of Hepatobiliary Phase On Gd-EOB-DTPA Enhanced MRI

Objective:To explore the optimum delay time in hepatobiliary phase Gd-EOB-DTPA enhanced MRI and its diagnostic value in clinic.Methods:68 cases (52 hepatitis and 16 health control) underwent Gd-EOB-DTPA enhanced MRI from July 2014 to January 2016 were analyzed, all cases were through intravenous contrast injection, followed by dynamic contrast phases and hepatobiliary phases at 20min, 1h,2h. ① Measured the signal intensity (SI) of the liver of hepatobiliary phase, erector muscle of spine and lesions, and calculate hepatobiliary phase liver SNR (signal to noise ratio), lesions CNR(contrast to noise ratio), liver muscle ratio, respectively. In all, we compared the differences of liver SNR, liver muscle ratio, and lesions CNR among 20min, 1h and 2h hepatobiliary phases in the two groups. ②The included 26 patients went through dynamic contrast MDCT, compare the detectable rate of focal lesion of MRI and MDCT. ③Record the time of gallbladder filled and the time of intrahepatic bile ducts showed, and intrahepatic bile ducts at hepatobiliary phase were evaluated by using a 5-point scale.Results:1.There were no statistical differences on liver SNR, liver muscle ratio after 20min, 1h, and 2h in the control group(P> 0.05), and neither hepatitis group did. After 20min delay, the liver SNR were no statistical differences in the two groups. After 1h and 2h delay, there were statistical differences in the liver SNR between two groups (P<0.05). After 20min, 1h and 2h delay, liver muscle ratio were statistical differences in the two groups. The CNR of HCC, sclerosis nodules, and angeioma were no statistical differences after 20min, 1h, and 2h.2.The detectable rate of Gd-EOB-DTPA enhanced MRI was 100%on lesions ≤1cm and 70%　for MDCT.3.According to dynamic enhanced of HCC was divided into 2 types, and the mean size of 21 typical HCC was 2.23±1.35cm, and 15 atypical HCC was 1.40±0.57cm. The mean size had statistical differences in the typical and atypical HCC.4.After 20min, 1h and 2h delay, the whole gallbladder filling were 18.8%,25.0% and 75.0%　in the control group, and its were 1.9%,32.7%　and 75.0%　in the hepatitis group. After 20min delay, there were statistical differences in the visualization rate of the bile duct between two groups. After 1h and 2h delay, there were no statistical differences in the visualization rate of the bile duct between two groups.5.The average of intrahepatic bile duct index was 2.21±0.81 in the control group, and its were 1.81±0.97,2.02±0.87 and 1.96±0.88 in the three period time of hepatitis group, there were no statistical differences.Conclusion:1. Hepatobiliary delay time of 20min, 1h and 2h after Gd-EOB-DTPA injection was sufficient for diagnosing HCC and evaluating the function of the liver.2. Detection of focal hepatic lesions≤1cm by Gd-EOB-DTPA enhanced MRI was higher than that the dynamic contrast MDCT.3. Hepatobiliary delay time of 2h after Gd-EOB-DTPA injection was better than 20min,1h on visualization of the bile duct.