Clinical Study of The Optimal Scan Delay Time in Multislice Spiral CT Portography of Cirrhosis

Objective To explore the optimal scan delay time for MSCT portography(MSCTP) in normal individuals and liver cirrhosis patients. Methods 15 normal individuals,18 patients with compensated hepatic cirrhosis and 30 patients with decompensated hepatic cirrhosis were involved in this study. Single-level dynamic CT scanning were performed at the level of slightly below the first liver hilus,the contrast dose was 1.5ml/kg and injection speed was 3ml/s,starting scan from 25s to 100s at 2.5s intervals,CT values of the portal vein and liver parenchyma were calculated at identical slice and the time-density curves were drawn. Results The average maximal value of the portal vein and the time for peak enhancement in normal group,compensated group and decompensated group were 205.5HU(49.0s)、186.7HU(51.3s)、169.2HU(62.9s),respectively. And the same measurements of hepatic parenchyma in three group were 118.8HU(60.4s)、112.4HU(64.8s)、102.4HU(75.4s),respectively. The average density differences between the portal vein and hepatic parenchyma(P-L) in three group were 87.3HU、74.3HU、67.0HU,respectively. Compare with normal group or compensated group,there were obvious statistical differences in decompensated group for the average maximal value and the time for peak enhancement of the portal vein and hepatic parenchyma(P0.05),there also had obvious statistical differences betwween normal group and conpensated group except the time for peak enhancement of the portal vein(P0.05). Conclusion When contrast dose was 1.5ml/kg and injection speed was 3ml/s in MSCTP,the optimal scan delay time in normal individuals or compensated hepatic cirrhosis patients should be 50s and decompensated hepatic cirrhosis patients should be 62s.