• Journal of the Korean Society of Radiology
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• v.13 no.6
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• pp.879-887
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• 2019

The purpose of this study is to establish a physiological injection protocol according to body weight, in order to minimize amount of contrast medium and optimize contrast enhancement in pediatric patients performing thoracic CT examinations. The 80 pediatric patients under the age of 10 were studied. Intravenous contrast material containing 300 mgI/ml was used. The group A injected with a capacity of 1.5 times its weight, and groups B, C and D added 5 to 15 ml of normal saline with a 10% decrease in each. The physiologic model which can be calculated by weight about amount of injection of contrast medium and normal saline, flow rate and delay time were applied. To assess image quality, measured average HU value and SNR of superior vena cava, pulmonary artery, ascending and descending aorta, right and left atrium, right and left ventricle. CT numbers of subclavian vein and superior vena cava were compared to identify the effects of reducing artifacts due to normal saline. Comparing SNR according to the contrast medium injection protocol, significant differences were found in superior vena cava and pulmonary artery, descending aorta, right and left ventricle, and CT numbers showed significant differences in all organs. In particular, B group with a 10% decrease in contrast medium and an additional injection of saline showed a low degree of contrast enhancement in groups with a decrease of more than 20%. In addition, the group injected with normal saline greatly reduced contrast enhancement of subclavian vein and superior vena cava, and the beam hardening artifact by contrast medium was significantly attenuated. In conclusion, the application of physiological protocol for injection of contrast medium in pediatric thoracic CT examinations was able to reduce artifacts by contrast medium, prevent unnecessary use of contrast medium and improve the effect of contrast enhancement.

• Journal of the Korean Society of Radiology
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• v.15 no.5
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• pp.575-584
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• 2021

The aim of this study was to achieve optimal portal phase while reducing contrast medium by applying weight-based dose protocol compared to standard fixed dose protocol to performing of pediatric abdominal CT examination. Discovery 750HD (General Electric Medical Systems, Milwaukee, USA) was used, and a total of 167 children consisting of 85 men and 82 women under the age of 18 were studied. The group in which the 300 mgI/ml(Xenetix, Guerbet, France) contrast medium was fixedly injected at twice body weight and the group injected with physiological saline while gradually decreasing the injection amount by 10% while applying the weight-based protocol were distinguished. Also, the CT number and SNR of abdominal organs were compared and evaluated while changing the scan delay time. Subjective image quality of enhancement and beam-hardening artifacts of around the heart was assessed with five-point criterion. The group adapted weight-based protocol with 20% reduction in contrast medium was most similar in contrast enhancement in the group with fixed injection at twice body weight. Furthermore, the group with a delay time of 20% had the highest contrast enhancement effect, and the difference in CT attenuation coefficient from the group scanned immediately after injection of the contrast media. Therefore, the appropriate delay time after injection of the contrast agent increased the contrast enhancement of the parenchymal organ. In addition, the weight-based injection protocol with normal saline reduced artifacts around the heart, and the effect of contrast enhancement could be maintained. In conclusion, it is possible to reduce dosage of contrast media through the application of weight-based injection protocols and appropriate latency, and to characterize optimal portal phase imaging on pediatric abdominal CT.

• Journal of the Korean Society of Radiology
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• v.5 no.2
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• pp.51-58
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• 2011

This research compared and analyzed the heart rate of the patient in which the LVEF value is 40% less than and normal patient. When as for LVEF 40% or less becomes to each heart rate and LVEF in a relation, we can know that the time to reach 100HU hangs long. Therefore, in patients, that is 40% less than, when setting up the Premonitoring delay, we could know to could give 5 primary solid phrases. It is seen that subsequently an addition injected 40cc as to Saline, to all patients by 4cc/sec speeds after injecting the capacity of Scan time ${\times}$ 4cc + 30cc with 4cc/sec speeds. And HR excludes 80 or greater in 40% less than, the contrast agent shows the large-scale difference. In addition, in 40% less than, it could predict that the time difference was big and the contrast agent was already out in the Left ventricle Wash- when the contrast agent reached 100HU and Scan was started There is a wide difference between under 40% LVEF and normal. when starting scan from low LVEF patients. So, Injection contrast media protocol Should be determined to CCTA. And then In case of low LVEF is recommended to more low Pitch than routine Pitch because we should reduce scan failed in accordance with low LVEF.

• Journal of Biomedical Engineering Research
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• v.20 no.2
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• pp.173-182
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• 1999

Contrast-enhanced CT has an important role in assessing liver lesions, the optimal protocol to get most effective result is not clear. The mein goal when deciding injention protocol is to optimize lesion detectability with rapid scanning when lesion to liver contrast is maximum. For this purpose, we developed a physiological model of the contrast medium enhancement based on the compartment modeling and pharmacokinetics. Blood supply to liver is achieved in two paths. This dual supply characteristic distinguishes the CT enhancement of liver from that of the other organs. The first path is by hepatic artery and to second, by portal vein. However, it is assumed that only gepatic artery can supply blood to hepatocellular carcinoma(HCC) compartment, thus, the difference of contrast enhancement is resulted between normal liver tissue and hepatic tumor. By solving differential equations for each compartment simultaneously using the computer program Matlab, CT contrast-enhancement curves were simulated. The simulated enhancement curves for aortic, hepatic, portal vein, and HCC compartments were compared with the mean enhancement curves from 24 patients exposed to the same protocols as the simulation. These enhancement curves showed a good agreement. Furthermore, we simulated lesion-to-liver curves for various injection protocols, and the effects were analyzed. The variables to be considered in the injection protocol were injection rate, dose, and concentration of contrast material. These data may help to optimize scanning protocols for better diagnosis.