An Experimental Study On Hepatic CT Perfusion Of The Superior Mesenteric Vein And The Splenic Vein Before And After Hepatic Fibrosis

PrefaceCT Perfusion Imaging, as a kind of functional imaging, can reveal the he-modynamic state of tissue and organs. Quantitation of hepatic perfusion proves a wide horizon of clinical application for its detection of hepatic lesions before the appearance of morphological changes. Nowadays, the contrast medium for hepatic CT Perfusion Imaging is usually injected intravenously and the portal perfusion is computed by simulating the splenic time - density curve with Blomley modified slope method.PurposeThis study aims to investigate the feasibility of intubation in the superior mesenteric artery (SMA) and the splenic artery (S_pA) to measure the portal purfusion with CT Perfusion Imaging and to observe the changes of hepatic perfusion and proportion of the superior mesenteric vein ( SMV) and the splenic vein (S_pV) before and after hepatic fibrosis respectively.Materials and methodsI Model building of hepatic fibrosisNine healthy adult dogs were selected at an average weight of 16. 5kg without the limitation of sex. They were injected with carbon tetrachloride in the abdomen and the diet was restricted but the free drink of alcohol. The course formodel building was 17. 6 weeks on average.II Methods for CT perfusionThe dogs for the experiment (9, but 5 remained after the model building) were fixed in the upper abdomen with a broad pressurizing belly band after anesthesia. After the femoral arteriopuncture, the catheter was intubated into the SMA and the splenic artery selectively. On the multiplayer spiral CT machine of Philips MX8000, the region of interest (ROI) was chosen with the SMV and the SPV in and also a good manifestation of the right hepatic lobe. The flow rate of the contrast agent was 2ml/s, and the total volume was 10ml.III Image postprocessingThe automatic analysis of softwares and the artificial measurement were combined during the imaging postprocessing. The maximal intensification value of the SMV and the SPV vein depended on the artificial measurement. The time - density curve was drawn and the superior mesenteric venous perfusion (SMVP) and the splenic venous perfusion (SPVP) were got from the automatic analysis of softwares. Thus the portal venous perfusion (PVP) and their proportion to the portal perfusion were calculated out. Meanwhile, the increment value of the liver parenchyma after intensification (increment = intensification peak density plain scan density,INC), the peak time (TTP) and the initial time of a-orta intensification were in hand.IV Statistical analysisThe data were analyzed with SPSS 11.5 paired t - test were done between groups. P value < 0.05 was considered of significant difference.Results5 models were built among which 3 were for early hepatic cirrhosis and 2 were for hepatic fibrotic hyperplasia. The perfusion studies were done on all the dogs (8 were normal, and 5 were in hepatic fibrosis) with ductus arteriosus technique. The results of some dogs in the SPV group were corrected by taking the spleen as the blood - supply vessel with computer softwares because of the severe influence of breath movements.