| Objective To investigate the application value of monochromatic energy image and iodine(water)-based image spectral CT in qualitative and quantitative diagnosis of active small intestinal hemorrhage without intestinal preparation,in order to estimate the blood loss in patients with active small intestinal hemorrhage relative accurately in a non-ideal state.Materials and Methods 5 New Zealand white rabbits,one 24 G venous indwelling needle,one micro pump and one micro pump extension tube are prepared.The two ends of the venous indwelling needle are connected with the micro pump delay tube and the intestinal wall respectively,the needle tubing should penetrate the intestinal wall and be fixed on it,then the micro pump is adjusted,set 0.1ml/min,0.2ml/min,0.4ml/min,0.6ml/min,0.8ml/min,1.0ml/min,1.2ml/min,1.4ml/min,1.6ml/min,1.8ml/min injection flow rate respectively to the rabbit colon of contrast agent injection,simulating intestinal bleeding.The configuration of the contrast agent was by two kinds of solution composition,300 mg I/ml iohexol and saline respectively,both according to the proportion of preparation about 1:45,to simulate contrast-enhanced blood.The different bleeding rates of the animal models were scanned by GE discovery HD750 64 row CT GSI mode,simulated the arterial phase and portal venous phase respectively with a delay of 15 s and 40 s.Each flow rate scanned 1 times,using GSI reconstruction to obtain 7 single energy images of 40 kev,50kev,60 ke V,70 kev,80kev,90 kev,100kev and the iodine-based image,selecting the best single energy 60 ke V to observe.To select all the levels of arterial and portal venous phase which the iodine can be observed in the iodine-based image of energy spectrum CT and measure the amount of iodine in the exudative area in the arterial,portal venous phase and the difference in the area of exudates between two periods of contrast,then the difference of iodine content between the arterial and portal phase was calculated(? IC = IC portal-IC arterial-IC background).Using the formula V determination= ? IC/(? t × ? I),and calculated the blooding flow rate(the unit of V determination is ml/min,? t is the interval time for arterial and portal phase scanning,the unit is s;? I is the concentration of iodine contrast agent,the unit is u g/cm3),using this method to estimate the blood volume of active small intestinal bleeding without intestinal preparation preliminarily.Through the paired t test and correlation analysis to analyze the relationship between the measured flow rate and the actual flow rate,and linear regression analysis was conducted.Results The real injection rate were 0.1,0.2,0.4,0.6,0.8,1.0,1.2,1.4,1.6,1.8 ml/min,corresponding to the experimental determination of flow rate were 0.132,0.23,0.456,0.688,0.928,1.176,1.40,1.614,1.846,2.062ml/min,respectively.Measured error rate between measured flow rate and the real flow rate were 32%,15%,14%,14.67%,16%,17.60%,16.67%,15.29%,15.38%,14.56%,respectively.With the increasing of real injection rate,when the real rate reaches a certain value(0.2ml/min),the measurement error between the real bleeding flow rate and the actual measurement of bleeding flow rate gradually decreases and tends to be stable,in other words,the difference between the actual measured flow rate and the real set flow rate decreases.The two groups of data between the real flow rate(0.910 ± 0.5896)and the measured flow rate(1.0532 ± 0.6773)has strong correlation through the regression analysis(r=1.000,P < 0.0001),reaching the regression equation of V true flow rate =0.871 V measured flow rate-0.007.Paired t test(t=4.897,P=0.001 < 0.05),the difference between the two values was statistically significant.Conclusion It is of certain value by using monochromatic energy image and iodine(water)-based image of spectral CT to calculate the active bleeding rate of the small intestine without intestinal preparation and to evaluate small intestinal active bleeding volume in a non-ideal state. |
PDF Full Text Request