| Objective: This research was based on animal experiments. To investigate the optimal dose of contrast medium and the optimal scan delay time in computed tomographic during arterial portography (CTAP) by using time-density curves, accordingly to provide the theoretical evidence in clinical application.Methods: 10 healthy crossbreeding dogs were involved in this study. Firstly, the catheter was sent into the superior mesenteric artery of each dog. Secondly, CT scanning was performed at the liver of the dog, defining the level of the first liver hilus. Thirdly, ionic contrast medium was injected six times at each dog, according to six doses of A,B,C , D, E, F ( concentration 306mgI/ml, injection rate 2m1/s) . CTAP and single-level dynamic CT scanning were performed at the level of the first liver hilus. Finally, the average maximum enhancement value and the time for peak enhancement of the liver were calculated by drawing the time-density curves.Results: The average maximum enhancement value of the liver (CT.)in A, B, C, D, E, F six doses were 47.01±11.44HU, 106.67±11.96HU, 160.41±24.72HU, 167.87±12.57HU, 194.38 ±34.63HU, 204.96±37.88HU respectively (P<0. 05) .The difference between C and D, E and F were insignificant (P> 0.05) and there was significant difference among the other doses (P<0. 05). The average time for peak enhancement of the liver (T.) were 39. 96±10. 42s, 28. 22±5. 79s, 31.72 ±4. 69s, 33.02±4. 53s,35. 54±3. 67s, 36. 23±11.68s, respectively (P<0. 05) . The differences between A and B, C, D, B and A, E were significant (P<0. 05) and there was no difference among the other doses (P>0. 05) .Conclusion: (1) In CTAP of dog, the liver could reach the optimal enhancement when contrast medium was injected in the dose of 2. 5ml/kg (concentration 306mgI/ml, injection rate 2ml/s) , scanning starting at 35. 54±3. 67s. (2) The liver of human could reach significant enhancement in this injection plan. |
