Basic Research On The Application Of Contrast Material At MSCT

Part 1 Different injection rate and different dose of the contrast material on TDC parametersObjective:To provide theoretical foundation for optimization of the contrast material by comparison of different dose and different flow rate of contrast material at multi-slice spiral computed tomography (MSCT) angiography.Materials and Methods:Sixty patients were randomly divided into three groups (group A, group B and group C; each group including 20 patients). The patients of group A were administrated intravenously 80mL of 300mgI/mL at a flow rate of 3.0mL/s, group B were 80mL,300mgI/mL,4.0mL/s, and group C were 100mL, 300mgI/mL,4.0mL/s. All underwent dynamic scanning at pulmonary trunk level with 64-slice computed tomography (CT). The pulmonary arterial peak time (PT), peak value (PV), the beginning time of more than 200Hu (Tb200) and duration time (T200) were analyzed.Results:To PT, Tb200 and PV, there were significant differences between group A and group B;To T200, there were no significant differences between group A and group B. To PV, PT and Tb200, there were no significant differences between group C and group B;To T200, there were significant differences between group B and group C.Conclusion:At MSCT, when the same dose and concentration of contrast material were administrated, the faster flow rate was used, the higher PV and the earlier PT of the artery were obtained. However, there were no significant differences of the duration of PT. Therefore, in order to obtain the better quality image, the faster flow rate should be used under the condition of no side effects. When the same concentration and flow rate of contrast material were administrated, the more dose of contrast material was used, the longer duration of peak time of the artery was obtained. However, there were no significant differences of PV and PT. Therefore, at MSCT, blind using the more dose of contrast material should be prohibited. However, the dose of the contrast material could not deduce without controled. The dose of contrast material should at least meet finishing the scan target organ duration of the peak time.Part 2 Different concentration of the contrast material on TDC parametersObjective:To provide theoretical foundation for optimization of the contrast material by comparison of different concentration of the contrast material on TDC paramenters at multi-slice spiral computed tomography (MSCT) angiography.Materials and Methods:Forty patients were randomly divided into two groups (group A and group B). The patients of group A were administrated intravenously 100mL of 300mgI/mL; the patients of group B were administrated 60mL of 400mgI/mL. All patients were injected at a rate of 4.0mL/s and underwent dynamic scanning at pulmonary trunk level with 64-slice spiral CT. The pulmonary arterial peak time (PT), peak value (PV), the beginning time of more than 200Hu (Tb200) and duration time (T200) were analyzed.Results:To PV, PT and Tb200, there were significant differences between group A and those of group B. To PV, group B was higher than group A; to PT and Tb200, group B was earlier than group A. To T200, there were significant differences between group A and group B, group A was longer than group B.Conclusion:At MSCT, when the same flow rate was administrated, the higher concentration of the contrast material was used, the higher peak value of the artery and the earlier peak time were obtained. However, the duration of peak time was connects with the dose of the contrast material, the more dose was used, the longer duration of peak time of the contrast material was obtained. Therefore, at MSCT, using the higher concentration of contrast material may deduce the dose, but the quality of the enhanced images can not decrease.Part 3 Comparative study on TDC of the different artery enhancementObjective:To comparative study on the parameters of time-density curve (TDC) of the different artery (take the pulmonary artery and the aorta for example), and to analyze the characteristics of the pulmonary artery and the aorta enhancement, so as to provide theoretical basis for multi-slice spiral computed tomography (MSCT) angiography.Materials and Methods:Fifty patients underwent dynamic scanning at pulmonary trunk level with 64-slice computed tomography (CT). All were administrated intravenously 80mL of 300mgI/mL at a rate of 4.0mL/s. The peak time (PT), peak value (PV) of pulmonary artery and aorta, the beginning time of more than 200Hu (Tb200) and duration time (T200) were analyzed.Results:The pulmonary arterial peak value was higher than that of aorta; The pulmonary arterial peak time and Tb200 were significantly earlier than that of aorta; To T200, there was no significant difference between the f pulmonary artery and aorta. The difference of the pulmonary artery and the aorta was (8.2±3.1)s. Conclusion:To the different cycle specificity of the artery, there were significant differences of peak value and peak time between the different arteries; to master the laws of the different artery is an important foundation for optimization of the contrast material at MSCT enhanced scanning and angiography.Part 4 Comparative study on TDC of the normal vascular and the abnormal tumor vascularObjective:To prospectively assess the TDC characteristics of the normal vascular (aorta) and the abnormal tumor vascular (take hepatocellular carcinomas for example). To analyze the relationship between the peak time of HCC and that of the aorta by using 64-slice computed tomography (CT).Materials and Methods:The study prospectively included 43 patients with known HCC. All underwent abdominal CT imaging by using BodyPerfusion CT model. The CT data acquisition was initiated delay 10-15 seconds from the beginning of the contrast material administered. The density-time curves (TDC) of the HCC and the aorta were drawn. The peak time of the HCC enhancement and that of the aortic enhancement were recorded, and the correlation between the peak time of the HCC and that of the aorta was analyzed.Results:The mean time to peak value of the aorta and the HCC was 23.38 seconds and 30.04 seconds, respectively. There were significant differences between the peak time of the aorta and that of the HCC. The peak time of the HCC was positively and linearly correlated with the peak time of the aortic enhancement (r=0.662, P<0.05). There were three tendencies of TDC of the HCC enhancement, only 23.3% of them were similar to that of the aorta.Conclusion:There were significant differences between the peak time of the aorta and that of the HCC. The peak time of the HCC was positively and linearly correlated with the peak time of the aortic enhancement. The result may potentially allow scan delay optimization at contrast material-enhanced CT image in the detection of HCC according to interindividual variability. At MSCT, selecting more reasonable delay time is of great significance because it can improve the detection rate of tumor lesions and their diagnostic accuracy.