.16-slice Spiral Ct Intrahepatic Portal Vein Imaging Technology Optimization And Intrahepatic Portal Vein Variation

Purpose: To optimize the portal vein(PV) scan delay-time of MSCTP(multi-slice spiral computed tomography portagraphy) by using test bolus techniques on spiral CT of sensation 16. To find appropriate dosage and concentration of contrast needed in MSCTP for patients with liver cirrhosis. To analysis variations of main branches of portal vein in healthy Chinese people. Methods: 111 healthy people and 65 patients with liver cirrhosis—Child A 30 cases, Child B 18 cases, Child C 17 cases—were adopted in this experiment. Test bolus techniques on spiral CT of sensation 16 were used , which contains three continual iso-level dynamic CT scan slightly below the liver hilus 8s after injection of Omnipaque(40ml, 5ml/s). Each scan lasted 25s with 7s between two neighboring scan. The time-density curves of the abdominal aorta(AA), the main trunk of portal vain(MTPV) and the hepatic parenchyma(HP) were generated automatically by Leonardo —a soft ware in CT. The peak time and maximum CT values of AA, MTPV and HP, showed on the time-density curves, were recorded respectively. Then , the PV scan delay-time—the peak time of MTPV was determined. 10min later , a whole liver scan was started right after this delay-time following the beginning injection of Omnipaque( 100ml or 80ml). Another liver scan was done 60s after the beginning injection of contrast. After that, MIP, VRT, SSD and MPRwere employed for 3-D reconstruction. PV branches and image quality were evaluated on MFP. According to MIP, a abirdged general view about branches—from grade one to three—of healthy people was drawn. SPSS 11.0 was used for statistics. Results: By use test bolus techniques, the time-density curves of AA, MTPV and HP were successfully obtained in each adopted case. There are no differences between the average peak time and maximum CT values of AA of healthy people and that of patients with liver cirrhosis(P>0.05). The average peak time of MTPV of healthy people and that of patients with liver cirrhosis is 42.2s and 34.5s,respectively; and there is difference between them(P<0.05). So does the maximum CT values of MTPV between healthy people(58.0HU) and patients with liver cirrhosis(49.9HU) (P<0.05). The average peak time and maximum CT values of HP of healthy people and that of patients with liver cirrhosis are 53.9s, 26.6HU and 62.5s, 24.5HU, respectively; and there are difference between them(P<0.05). Patients of ChildEK C have a longer average peak time (43.8s) and a lower average maximum CT values(48.2HU) than that of Child A ones(40.5s, 51.4HU), but there are no difference between them (P>0.05). 65 cases with liver cirrhosis were randomly divided into three groups— Omnipaque 80ml (300mg/ml) group, Omnipaque 100ml (300mg/ml) group and Iopamidol 100ml(370 mg/ml) group. Each group were received contrast at the same speed (5ml/s). During evaluation of PV branches and image quality, Iopamidol 100ml(370 mg/ml) group had higher scores than that of Omnipaque 80ml group and Omnipaque 100ml group(P<0.05). There are seven types of PV variation in 111 healthy people, and the variation rate is 33.3%. Conclusions: 1. The average peak time of MTPV of patients with liver cirrhosis is longer than that of healthy people at the same speed (5ml/s).ChildEk C have a longer average peak time (43.8s) than that of Child A ones(40.5s), but there is no difference between them (P>0.05). 2. Iopamidol 100ml(370 mg/ml) is proposed to be used in patients with liver cirrhosis. The scan delay-time can be determined by test bolus techniques or be around 43s. 3. There are seven types of PV variation in 111 healthy people, and the variation rate is 33.3%.