• Journal of radiological science and technology
• /
• v.41 no.2
• /
• pp.123-128
• /
• 2018

Recently, the use of contrast agents has been increasing as a broader range of tests and dynamic tests have become common due to the development of equipment and imaging techniques such as Multi-Detector CT. However, the side effects of using contrast agents have been reduced by the development of non-ionic contrast agents, but they are still occurring often. The purpose of this study was to propose a method to minimize the side effect of contrast agent by using the amount of contrast agent injected to the brain angiography test to suppress excessive use of contrast agent and analyze the amount of contrast agent. Patients who were prescribed Brain Angiography due to cerebrovascular disease, According to the results of the comparison of the results obtained by dividing into 4 groups of 10ml each according to the amount of contrast medium injected with contrast agent according to the BMI of the patient, BA and SNR were not different between groups, and even if the amount of contrast injection was reduced, there was no problem in the evaluation of CT angiography through 3D reconstruction. This result shows that even if the contrast medium is injected into the blood vessels of the patient first and then the contrast medium is used as the physiological saline solution, the contrast medium is reduced by 40% it can be expected to minimize.

• Investigative Magnetic Resonance Imaging
• /
• v.15 no.2
• /
• pp.139-145
• /
• 2011

Purpose : To assess the frequency and severity of acute adverse reactions to intravenous administration of gadolinium-based contrast agents using computerized reporting system at a single large academic institution. Materials and Methods : We assessed data from electronic hospital information system from October 2008 to December 2010. Reactions were classified as mild, moderate, or severe. We compared the frequency of adverse reactions among three contrast agents (Gd-BT-DO3A, Gd-DTPA and Gd-EOB-DTPA). Results : The total number of administrated contrast agents was 33,600, and the number of administration of Gd-BT-DO3A, Gd-DTPA and Gd-EOB-DTPA were 20,824 (62%), 10,417 (31%) and 2,359 (7%), respectively. Total 39 adverse reactions were reported accounting for 0.1161% of all administrations. The incidences of adverse reactions were 0.1248% (26/39, 67%) for Gd-BT-DO3A, 0.0768% (8/39, 21%) for Gd-DTPA, and 0.2120% (5/39, 13%) for Gd-EOB-DTPA. The difference of frequencies of adverse reaction among three contrast agents was not significant. Most cases of the adverse effect were mild (35/39, 89.7%). Moderate and severe adverse reactions were encountered in two patients, respectively. Conclusion : Among Koreans, adverse effects were rare, and especially, moderate to severe adverse reactions were much rarer. There was no difference among the frequencies of adverse reactions caused by three different contrast agents.

• Journal of the Korean Society of Radiology
• /
• v.11 no.7
• /
• pp.589-595
• /
• 2017

This study evaluated the effect of gadolinium contrast agents on the spectrum of metabolites during $^1H-MRS$ of brain and to investigate whether the contrast agents injected before MR spectroscopy significantly affect the estimated peaks of MRS. From January to May 2017, brain MR spectroscopy was performed on 30 patients to compare the spectrum before and after contrast injection of the brain white matter tissue. As a result, the spectrum of metabolites decreased after the paramagnetic contrast agents injected. However, it was not statistically significant which indicated that the use of contrast agent did not meaningfully affect the spectrum of metabolites. In conclusion, the use of the paramagnetic contrast before the acquisition of the spectroscopy may aid voxel positioning especially when it is difficult to determine the exact location of the lesion or the contrast is low.

• Journal of Radiopharmaceuticals and Molecular Probes
• /
• v.1 no.2
• /
• pp.130-136
• /
• 2015

We evaluate the influence of MR contrast agent on positron emission tomography (PET) image using phantom, animal and human studies. Phantom consisted of 15 solutions with the mixture of various concentrations of Gd-based MR contrast agent and fixed activity of [$^{18}F$]FDG. Animal study was performed using rabbit and two kinds of MR contrast agents. After injecting contrast agent, CT or MRI scanning was performed at 1, 2, 5, 10, and 20 minutes. PET image was obtained using clinical PET/CT scan, and attenuation correction was performed using the all CT images. The values of HU, PET activity and MRI intensity were obtained from ROIs in each phantom and organ regions. In clinical study, patients (n=20) with breast cancer underwent sequential acquisitions of early [$^{18}F$]FDG PET/CT, MRI and delayed PET/CT. In phantom study, as the concentration increased, the CT attenuation and PET activity also increased. However, there was no relationship between the PET activity and the concentration in the clinical dose range of contrast agent. In animal study, change of PET activity was not significant at all time point of CT scan both MR contrast agents. There was no significant change of HU between early and delayed CT, except for kidney. Early and delayed SUV in tumor and liver showed significant increase and decrease, respectively (P<0.05). Under the condition of most clinical study (< 0.2 mM), MR contrast agent did not influence on PET image quantitation.

• Investigative Magnetic Resonance Imaging
• /
• v.4 no.1
• /
• pp.27-33
• /
• 2000

Purpose: To determine the electronic spin relaxation times, $T_{le}$, of three commercially available Gd-chelated MR contrast agents, Gd-DTPA, Gd-DTPA-BMA and Gd-DOTA, using Electron Paramagnetic Resonance(EPR) technique. Material and Methods: The paramagnetic MR contrast agents, Gd-DTFA(Magnevist) , Gd-DTFA-BMA(OMNISCAN) and Gd-DOTA(Dotarem), were used for this study, The EPR spectra of these contrast agents, which were prepared 2:1 methanol/water solution, were obtained at low temperatures, from $-160^{\circ}C~20^{\circ}C$. The glassy-state EPR spectra for these contrast agents were then fitted by the simulation spectra generated with different zero-field splitting (ZFS) parameters by a computer simulation program 'GEN', which generates the EPR powder spectrum using a given ZFS in $3{\times}3$ tensor. Finally, the spin relaxation times of the contrast agents were then determined from the $T_{2e}$, D, and E values of the best simulation spectra using the McLachlan's theory of average relaxation rate. Results: The electronic transverse spin relaxation times, $T_{2e}'s$, of Gd-DTPA, Gd-DTPA-BMA and Gd-DOTA were 0.113ns, 0.147ns and 1.81ns respectively. The g-values were 1.9737, 1.9735 and 1.9830 and the electronic spin relaxation times, $T_{1e}'s$, were 18.70ns, 33.40ns and $1.66{\mu}s$, respectively. Conclusion: The results of these studies reconfirm that the paramagnetic MR contrast agents with larger ZFS parameters should have shorter $T_{1e}'s$. Among three contrast agents used for this study, Gd-DOTA chelated with cyclic ligand structure shows better electronic property then the others with linear structure. Thus, it is concluded that the exact determination of ZFS parameters is the important factor in evaluating relaxation enhancement effect of the agents and in developing new contrast agents.

• The Journal of the Acoustical Society of Korea
• /
• v.28 no.1E
• /
• pp.1-8
• /
• 2009

Primary radiation force on ultrasound contrast agents (UCA) in a propagating and standing acoustic field was explored. A specific ultrasound contrast agent $Albunex^{(R)}$ and $Optison^{(R)}$ were chosen for simulation. The model was developed based on a shelled bubble model proposed by Church. The numerical simulation suggests that bubble translational motion is more significant in therapeutic ultrasound due to higher intensity and long pulse duration. Even a single cycle of a propagating wave of 4 MPa at 1 MHz can cause a bubble translational motion of greater than $1{\mu}m$ which is approximately one tenth of capillary. Hence, UCA characteristics can be significantly changed in therapeutic ultrasound without rapid bubble collapses.

• Korean Journal of Radiology
• /
• v.22 no.5
• /
• pp.677-687
• /
• 2021

Microvascular ultrasound (US) techniques are advanced Doppler techniques that provide high sensitivity and spatial resolution for detailed visualization of low-flow vessels. Microvascular US imaging can be applied to breast lesion evaluation with or without US contrast agents. Microvascular US imaging without a contrast agent uses a sophisticated wall filtering system to selectively obtain low-flow Doppler signals from overlapped artifacts. Microvascular US imaging with second-generation contrast agents amplifies flow signals and makes them last longer, which facilitates hemodynamic evaluation of breast lesions. In this review article, we will introduce various microvascular US techniques, explain their clinical applications in breast cancer diagnosis and radiologic-histopathologic correlation, and provide a summary of a recent radiogenomic study using microvascular US.

• KIPS Transactions on Software and Data Engineering
• /
• v.4 no.7
• /
• pp.297-300
• /
• 2015

In medical ultrasonography, transit time and contrast enhancement patterns are considered as important parameters to analyze liver diseases. In many recent researches, time-intensity curves(TIC) have been used for calculating the transit time of the contrast agents. However, the intensity curve may include the variations which are caused by the micro-bubble effect of contrast agents. In this paper, we propose a complementary approach to diagnostic parameter extraction which utilizes a density information as well as the intensity data. The proposed technique improves the accuracy in extraction of the transit time and velocity of contrast agents for detection and characterization of focal liver lesions. Through the experiments using a set of clinical data, we show that the proposed methods can improve the reliability of the parametric image data.

• Journal of the Korea Safety Management & Science
• /
• v.16 no.4
• /
• pp.427-431
• /
• 2014

The purpose of this study is to monitor the current adverse reactions in administering CT contrast agents at general hospitals and also to suggest the practical guidelines to minimize the risk and to show the successful patient management. At four Dajeon city general hospitals, the contrast agents were administered in 646,828 cases and the overall prevalence of adverse reactions was 4,110 cases from January 2010 to December 2013. However, we excluded the two hospitals' 3,658 cases because the patients' data was inadequate. Consequently, the case surveys on the rest of 452 cases have been studied and submitted. After comparing the patients with a control group, we evaluated that the key factors of the adverse reactions were the gender and age difference of the patients, the examination period, the examination method, the quantity and administrating speed of the contrast agents. Even though the four general hospitals have their own management systems on adverse reactions, but their systems were not satisfying. To improve the quality of the management systems and to investigate further cases, some hospital administration procedures on the subject should be systemized and general hospitals should follow the recommended procedures. Moreover, the existing three-year-term evaluation should not only judge the adverse reaction management but also conclude some details on the sub criteria of the evaluation. The details on the sub criteria include the contrast agent characters, the quantity and administrating speed of the drug, the incidents' occurred time, an anamnesis; a case history, the medical history of the patients and the reaction occurring body parts, and the examination title. The details of the medical examiners are also added to the sub criteria.

• Ultrasonography
• /
• v.32 no.1
• /
• pp.59-65
• /
• 2013

Purpose: The purpose of this study is to establish the methodology regarding synthesis of ultrasound contrast agent imaging, and to evaluate the characteristics of the synthesized ultrasound contrast agents, including size or degradation interval and image quality. Materials and Methods: The ultrasound contrast agent, composed of liposome and SF6, was synthesized from the mixture solution of $21{\mu}mol$ DPPC (1, 2-Dihexadecanoyl-sn-glycero-3-phosphocholine, $C_{40}H_{80}NO_8P$), $9{\mu}mol$ cholesterol, $1.9{\mu}mol$ of DCP (Dihexadecylphosphate, $[CH_3(CH_2)_{15}O]_2P(O)OH$), and chloroform. After evaporation in a warm water bath and drying during a period of 12-24 hours, the contrast agent was synthesized by the sonication process by addition of buffer and SF6 gas. The size of the contrast agent was controlled by use of either extruder or sonication methods. After synthesis of contrast agents, analysis of the size distribution of the bubbles was performed using dynamic light scattering measurement methods. The degradation curve was also evaluated by changes in the number of contrast agents via light microscopy immediate, 12 hours, 24 hours, 36 hours, 48 hours, 60 hours, 72 hours, and 84 hours after synthesis. For evaluation of the role as an US contrast agent, the echogenicity of the synthesized microbubble was compared with commercially available microbubbles (SonoVue, Bracco, Milan, Italy) using a clinical ultrasound machine and phantom. Results: The contrast agents were synthesized successfully using an evaporation-drying-sonication method. The majority of bubbles showed a mean size of 154.2 nanometers, and they showed marked degradation 24 hours after synthesis. ANOVA test revealed a significant difference among SonoVue, synthesized contrast agent, and saline (p < 0.001). Although no significant difference was observed between SonoVue and the synthesized contrast agent, difference in echogenicity was observed between synthesized contrast agent and saline (p < 0.01). Conclusion: We could synthesize ultrasound contrast agents using an evaporation-drying-sonication method. On the basis of these results, many prospective types of research, such as anticancer drug delivery, gene delivery, including siRNA or microRNA, targeted molecular imaging, and targeted therapy can be performed.