Functional CT Imaging For Quantifying Normal Hepatic Tissue And VX2 Tumor Perfusion In A Rabbit Model

Objective To study the influence of various doses and injection rates of contrast agent and slice thickness on hepatic perfusion CT with a deconvolution mathematical model. To establish the model of hepatic VX2 tumor in rabbits with an improved method, and to evaluate the advantage of multi-slice CT in the monitoring of tumor growth. To quantify liver VX2 tumor perfusion on various time points and detemine the histologic basis of perfusion parameters measured by fuctional CT and explore the correlation between perfusion and angiogenesis features evaluated by immunohistochemical microvascular staining.Materials and Methods 40 normal New Zealand rabbits were used in this study, of which, 8 rabbits were randomly enrolled into the first experiment. Randomized block design was adopted. The treatment factor - contrast medium injection rate was classified into 0.5,1.0,1.5ml/s; the subjects were divided into 3 blocks by contrast medium injection dose: 0.5,1.0, and 1.5ml / kg. Besides, an additional scan group with 2.5mm slice thickness was taken in the group of 1.5ml/s and 1.5 ml/kg. The data obtained at perfusion CT imaging were then transferred to the workstation. Absolute values of seven perfusion parameters—hepatic arterior fraction, blood flow, blood volume, permeability surface, mean transmit time, hepatic artery perfusion and portal vein perfusion were measured by using perfusion software (Liver Tumor Perfusion 3;GE Medical systems). The remain 32 rabbits were used to establish 29 VX2 liver tumor models and 3 as tumor carrier. Micro-pieces of VX2 tumor excised from the carrier rabbit were implanted onto hepatic lobe with the outer cannula of a 5F angiocatheter via laparotomic route. Every model was randomly enrolled into four groups according to the time of tumor implantation (7d, 10d, 15d, 21d). The models...