| Objective: The goal of this paper is to Study the perfusion and volume of normal liver in healthy volunteers at different altitudes by MSCT,and then to see wether they have some differences in the perfusion and volume of livers that in status of chronic hypoxia for a long time.Materials and methods: 60 Volunteers ( 37 male cases and 23 female cases ),whose average age is ( 40.3±5.7) ,The volunteers were divided into three groups named A,B,C respectively. Group A involved 22 cases,with the altitude of 2260-3260 m; Group B has 20 cases,with the altitude of 3261-4260 m; Group C has 18 cases,with the altitude of 4261-5260 m. All the volunteers are adults with normal liver function that have no hypertension , heart diseases or liver diseases and they have no hepatitis virus markers detected. They are all the natives of plateau region who have signed on the informed consent.The scanner we chose was Brilliance Philips 16 row helical CT, Japan Nemoto CT with single cylinder high-pressure syringe. Liver CT perfusion imaging scans :(1) Preparation for check: 4 hours abrosia ,intestinal canal which was filled with 750 ~1000 ml fresh water 30 minutes before checking.(2) Supine position, the first step is to scan the whole liver (including the top and the lower edge of the liver) using conventional CT, then to select the perfusion scan layer, usually made the hepatic portal area as the center, portal vein and hepatic artery showed clearly, including the layer of the spleen. (3) Perfusion scan: We chose same-layer continuous dynamic scanning model, contrast agents Ultravist show (300mgI/m1) 50ml,the injection velocity is 5ml/s, and synchronous scan after injection contrast agents. Teleporting the reconstructed image produced by CT scan to workstations, analysis and calculation by CT perfusion software, measure the hepatic artery perfusion (HAP), portal vein perfusion (PVP), total liver perfusion (TLP) and hepatic perfusion index (PHI).(4) Measurement of liver volume: using point circle method to artificial draw the outline of the edge of each layer in liver, and then use the CT perfusion software of workstation obtain the each area, and calculate the each volume by thickness of each layer, then added the each layer,s volume will be the liver volume. When you selected should be keep the main branch of blood vessel which in split liver, gallbladder, inferior vena cava and hepatic portal vein.Statistical processing with SPSS 17.0 software. Comparing the mean of parameters with in three groups, analysis the differences of them. Results: (1)The observation of each groups with liver CTmanifestations, the morphology and size of the liver are normal,and the liver crack is not wide, there is not abnormal density shadows inside liver. The morphology and size of Spleen are normal, and there is not abnormal density shadows inside spleen. (2) HAP: The values in group A,group B and grou p C are 10.50±3.62 mL / (100ml·min), 15.03±4.27 mL / (100ml·min), 18.39±7.20 mL / (100ml·min) respectively. There do not have statistically significance between group A and group B,the same between group B and group C (p>0.05), there was a statistically significance between group A and group C (p <0.05).(3)PVP:The values in group A,group B and group C are 138.78±14.29 mL / (100ml·min), 80.42±16.80 mL / (100ml·min), 63.78±7.79 mL / (100ml·min) respectively. The differences between group A and group B, group B and C , group A and group C have statistically significance (p <0.05).(4) TLP: The values in group A,group B and group C are 149.30±15.55 mL / (100ml ·min), 95.57±18.75 mL / (100ml·min), 82.19±10.56 mL / (100ml·min) respectively. The differences between group A and group B, group B and C, group A and group C have statistically significance (p<0.05).(5)HPI:The values in group A, group B and group C are 7.00±2.17,16.27±4.22, 22.05±7.90 respectively. The differences between group A and group B,group B and C, group A and group C have statistically significance (p<0.05).(6)The liver perfusion status clearly visual displayed by Perfusion color figure (red and blue stands for high perfusion area - low blood perfusion area). (7) Liver volume:The values in groupA,groupB and groupC are 1173.5±155.2cm3,1482.9±362.2cm3,1625.4±352.2cm3 respectively. The differences between group A and group C have statistically significance (p <0.05). The differences between group A and group B, group B and group C do not have statistically significance(p> 0.05).Conclusion: The paper described the perfusion and volume changes of haemodynamics in liver at different altitudes through the MSCT.The factor of altitude directly affect the liver perfusion. HAP,HPI and liver volume will gradually raise with the altitude increasing,PVP and TLP gradually decrease with the altitude increasing. The result showed that MSCT perfusion imaging of the liver may reflect the state of long-term liver hemodynamic changes in chronic hypoxia status, which proved the evidence for studing on informance of perfusion in liver at long-term hypoxia enviroment.It is also in favour of the diagnosis, treatment and functional evaluation of plateau liver diseases. MSCT can quickly scan, its high time, high spatial resolution can make the evaluation of liver hemodynamic changes rapidly, accurately and noninvasive. |
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