Study Of256-Slice CT Whole Organ Perfusion Imaging In Pancreatic Adenocarcinoma

To access the whole organ perfusion characteristics of normal pancreas and pancreatic adenocarcinoma using a256-slice CT perfusion and to find out the value of whole pancreatic perfusion CT imaging in the application of pancreatic carcinoma. Furthermore, the expression of microvascular density was measured in pancreatic adenocarcinoma. And the relation between CT perfusion and angiogenesis of pancreatic carcinoma was discussed.Part I Whole Organ CT Perfusion Imaging for Normal PancreasObjective:To explore the whole organ perfusion characteristics of normal pancreas using a256-slice CT perfusion and to find out the normal range of perfusion parameters, which is the baseline for following study.Materials and Methods:Whole pancreas CT perfusion imaging was performed in26patients without pancreatic diseases from January2011to March2013using a256-silce CT scanner (Brilliance iCT, Philips Medical Systems, USA),100kVp,100mAs,5mm slice thickness, field-of-view350mm,512X512pixels. Using a high pressure syringe,50mL of nonionic contrast agent (Iopamidol,370iodine/mL) was administered at a flow rate of5mL/s through a21-gauge intravenous catheter, followed by a saline flush of30mL (5mL/s) serving as a bolus chaser. The protocol for whole pancreas CT perfusion contained of a total of13intermittent volume acquisitions, which were acquired over a time period of85seconds. A volume acquisition was performed every7seconds:2seconds of scanning time and5seconds of interval time. The raw data were reconstructed using the iDose4algorithm (Philips Healthcare). Images data were processed using a workstation with professional perfusion software (MIStar, Version3.2), and the mean values of BF, BV, PS and MTT were measured and statistically analyzed in normal pancreas.Results:The mean values of BF, BV, PS and MTT of normal pancreas were114.08±20.62mL/100g/min,19.34±2.45mL/100g,29.01±4.10mL/100g/min,7.12±2.19s respectively, and without significantly difference in the head, body and tail (P>0.05). Conclusions:Whole pancreas CT perfusion imaging shows that the normal pancreas displayed as an organ with symmetrical blood volume, blood flow, permeability surface area product and mean transit time.Part II Whole Organ CT Perfusion Imaging for Pancreatic AdenocarcinomaObjectives To measure the whole organ perfusion parameters of normal pancreatic adenocarcinoma and to explore the characteristic of CT pancreatic adenocarcinoma using a256-slice CT.Materials and Methods:Whole pancreas CT perfusion imaging was performed in36patients with pancreatic adenocarcinoma from January2011to March2013. Images data were processed using a workstation with professional perfusion software (MIStar, Version3.2), and the mean values of BF, BV, PS, MTT and PS/BF were measured and statistically analyzed in pancreatic adenocarcinoma.Results:The mean values of BF, BV, PS, MTT and PS/BF of pancreatic adenocarcinoma were30.59±9.46mL/100g/min,6.59±2.41mL/100g,15.56±4.29mL/100g/min,7.69±3.11s and0.533±0.189respectively. Comparing with the normal pancreas, pancreatic adenocarcinoma had significantly difference in BV, BF, PS and PS/BF, while MTT was no significant difference.Conclusions:The characteristic of pancreatic adenocarcinoma CT perfusion imaging is significant decrease of blood flow, blood volume, permeability surface area product and remarkable increase of PS/BF.Part Ⅲ Correlations of Microvessel Density of Pancreatic Adenocarcinoma and Whole Pancreas CT Perfusion ParametersObjective:To explore the correlations of microvessel density of pancreatic adenocarcinoma and the whole organ CT perfusion parameters, in order to evaluate the angiogenesis of the pancreatic adenocarcinoma.Materials and Methods:19pancreatic adenocarcinoma specimen and paracarcinoma pancreatic tissues were studied. Microvascular density is measured by CD31staining with mean of19microvessel views in pancreatic adenocarcinoma, peritumoral tissues and normal pancreatic tissues. Data were analyzed statistically by spearman correlations.Results:The mean values of microvessel density of pancreatic adenocarcinoma, peritumoral tissues and normal pancreatic tissues were122.25±40.21,245.85±40.17, 311.35±52.03respectively. The mean MVD of pancreatic carcinoma is obviously lower than normal pancreatic tissues, and positive correlated with BF values (P<0.0001,r=0.874).Conclusions:The microvessel density of the pancreatic adenocarcinoma is correlated with CT perfusion parameter BF. And CT perfusion can be used as an imaging method to evaluated tumor angiogenesis in vivio.