Model Study On Iodine-based Image Spectral CT In Quantitative Diagnosis Of Small Intestinal Active Bleeding

Objective To explore the value of quantitative analysis of the small intestinal active bleeding by the iodine-based image spectral CT so that estimate the blood loss more accurate in patients with acute active small intestinal bleeding.Methods Made by in vitro pig small intestine hemorrhage model, with a 24 g venous indwelling needle trace syringes are connected at one end, and to the other end of the needle through the intestinal wall and should be fixed on the intestinal wall, then adjust trace syringes, respectively 0.1 ml/min, 0.2 ml/min, 0.3 ml/min, 0.4 ml/min, 0.5 ml/min inside the injection flow rate to the model of injection of contrast medium. The configuration of the contrast medium was by 300mg/ml Omnipaque made 1:45proportion with physiological saline and CT value is about 280HU~300HU.For each rate,a GE Discovery HD750 CT scanner was used in GSI scan mode and 64 slice CT was performed,with a delay of 15 s and 40 s simulated the arterial phase and portal venous phase,respectively.The iodine-based image of energy spectrum CT was used to select the levels of arterial and portal venous phase which the iodine can be observed and calculate the amount of iodine in the arterial and portal venous phase, then calculated the difference of the arterial and portal phase iodine content(△ IC = IC portal- IC arterial).Determined by formula V = Δ IC/(Δ t * ρI), and calculate the rate of blood flow(Δ t between the arterial phase and portal phase scanning time interval, ρI unit iodine content of iodine contrast agent), V is the determination of the unit is ml/min, to a preliminary estimate intestinal active blood loss. Using correlation analysis and t test analysis the relationship between the actual flow rate and the measured flow rate.Results The actual injection flow rate were 0.1, 0.2, 0.3, 0.4, 0.5 ml/min and the experimental flow rate were 0.0712, 0.2566, 0.3587, 0.4685, 0.5594 ml/min. Measured error rate between flow rate and the actual flow rate were 28.77%, 28.30%, 19.57%,28.30%, 11.88%, with the increase of the injection flow rate measurement error became smaller, and the measured flow rate with the increase of the injection flow rate gradually close to the actual flow rate. The two has significant correlation through the regression analysis(r = 0.984, P < 0.05) and there is no statistically significant difference between two groups(P > 0.05).Conclusion It is feasible by using the iodine iodine-based image of energy spectrum CT to estimate the blood flow rate of the small intestine active bleeding.