• Journal of the Korean Society of Radiology
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• v.5 no.3
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• pp.143-148
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• 2011

The purpose of this study was to examine the usefulness of SPIO contrast agent in Magnetic Resonance Cholangiopancreatography (MRCP) by performing a quantitative comparative analysis in patients undergoing MRCP for gallbladder stones with and without oral injection of SPIO (Superparamagnetic iron oxide) contrast agent. The subjects were 36 patients undergoing MRCP for suspected gallbladder stones between January 2009 and February 2010 and they were divided into halves to compare the two groups of with and without SPIO agent. For each subject in both the injected and non-injected group, T2-weighted images on a 1.5T MR scanner were obtained, using both the breath-holding and respiratory-triggered methods, respectively. The following regions were measured; for breath-hold T2-weighted images, the measurement regions were located at the central part of the gallbladder, and the areas 15 mm away from its center, toward the front and back, respectively, which were chosen to include surrounding tissues, while for respiratory-triggered T2-weighted images, at the central part of the gallbladder, and segment 5 and 6 of liver. In a quantitative analysis, average signal to noise ratio (SNR) in each of regions of interest (ROI) for each group were calculated and then average contrast to noise ratio (CNR) in each of ROI were obtained by using the SNR in the gallbladder as the basis to compare and analyze the values between the two groups. The CNR were higher for the injected group in those regions.

• Investigative Magnetic Resonance Imaging
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• v.19 no.3
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• pp.191-195
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• 2015

We present a 53-year-old woman with a large chest wall mass in the interpectoral space, which was eventually confirmed as a lipogranuloma resulting from hydrogel implant rupture. Ultrasonography (US) showed reduced implant volume with surrounding peri-implant fluid collection, suggesting the possibility of implant rupture. A heterogeneously hypoechoic mass was found between the pectoralis major and minor muscles adjacent to the ruptured implant. On magnetic resonance imaging (MRI), there was a large mass in the left interpectoral space of the upper inner chest wall. The mass showed slightly high signal intensity (SI) on pre-contrast T1-weighted image (WI) with mixed iso and high SI on T2-WI. The signal of the mass was suppressed using the water suppression technique but not with the fat suppression technique on T2-WI. The mass showed diffuse enhancement upon contrast enhancement. The enhancing kinetics showed persistent enhancement pattern. US-guided core needle biopsy revealed a lipogranuloma and removal confirmed a ruptured PIP hydrogel implant.

• Nuclear Medicine and Molecular Imaging
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• v.40 no.3
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• pp.186-187
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• 2006

A 64-year-old female with glioblastoma multiforme (GBM) was assigned to our department for whole body PET/CT scan. She ingested 1 liter of pure water as negative oral contrast just before PET/CT examination. FDG-PET/CT images showed a very intense hypermetabolic, focal lesion in the abdominal cavity around descending colon. The SUVmax of the lesion was 17.2. But there was no abnormal lesion corresponded to the area of PET scan in the combined contrast enhanced CT scan. We suggested considering a malignant lesion due to very intense glycolytic activity. Conventional abdominal CT scan & colonoscopy were accomplished within one week after PET/CT evaluation. There was no abnormality in both examinations. We executed follow-up PET/CT evaluation after 1 month and couldn't find any abnormality around the corresponding area. So we concluded the hypermetabolism was colonic physiologic uptake. A colonic physiologic uptake is a well known cause of false positive finding. Nuclear physicians should be considered the possibility of malignancy when interpret focal colonic uptake, especially incidental finding. There are a few reports that using of negative oral contrast is able to reduce gastrointestinal physiologic uptakes. But as we can see in this case, although we used negative oral contrast, intense physiologic uptake is detected and maxSUV is able to up to 17.2. So, it is important to keep a fact in mind. Even though there is a colonic physiologic uptake in PET/CT image, it may be able to show very intense hypermetabolism regardless of using negative oral contrast.

• Bulletin of the Korean Chemical Society
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• v.30 no.4
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• pp.849-852
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• 2009

The work describes EPR and 17O NMR measurements followed by theoretical calculation of the rotational correlation time $({\tau}_R)$, the water residence time $({\tau}_m)$, and the longitudinal electronic spin relaxation time $(T_{le})$(T_1e) for two new gadolinium complexes 1 and 2 of the type [$Gd(L)(H_2O)$] (L = tranexamic esters) in order to investigate their efficiency as a paramagnetic contrast agent (PCA). Of three correlation times, τR plays a major and predominant role to the unusually high relaxivity of 1 and 2 as compared with that of clinically approved MR CAs such as [$Gd(DTPA)(H_2O)]2‐ (Magnevist${\circledR}$), [Gd(DTPA-BMA)(H2O)] (Omniscan${\circledR}$), and $[Gd(DOTA)(H_2O)]^-$ (Dotarem${\circledR}$). The presence of bulky tranexamic ester in the ligand seems to be responsible for the conformational rigidity, which in turn causes such great an increase in ${\tau}_R$.

• Progress in Superconductivity
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• v.10 no.2
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• pp.123-127
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• 2009

NaFeAs recently observed superconductivity with the maximum $T_c{\approx}25$ K is investigated using first principles approach. We will address briefly the electronic structure and contrast other superconducting pnictides. This system shows strong two-dimensionality and reduction of flatness in the Fermi surfaces undermines tendencies of magnetic or charge instabilities. As observed in other superconducting pnictides, $Q_M=(\pi,\pi,0)$ antiferromagnetic ordering, which has not been observed clearly yet in this compound, is energetically favored. However, contrast to other superconducting pnictides, the density of states in this ordering shows considerable electron-hole asymmetry, implying efficiency of hole-doping than electron-doping to enhance $T_c$.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.12
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• pp.131-138
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• 2016

In this study, we tried to analyze the influence of ICM(Iodinated Contrast Media) in MR imaging compare to GBCA(Gadolinium Based Contrast Agent), and as this result we discussed whether resonable or not the protocol which is MRI scan after enhanced CT scan without proper time interval in clinical field. For this research, we assembled two phantoms. which one was iodine and another one was gadolinium. We did test two phantoms in conventional MRI scan which is T1, T2, T2 FLAIR and 3D angio. After that, quantitative analysis was progressed. The results of study were as follow : SSI(Saline's Signal Intensity) was shown as each sequences 175, 1231, 333, 37 [a.u] at iodine. and 1297, 123, 757, 232 [a.u] was recorded at gadolinium. BDEPS(the Biggest Difference of EPS) was shown as each sequences 1297, 123, 757, 232 [a.u] at iodine and 793, 6, 1495, 365 [a.u] was recorded at gadolinium. At this time, EPS(Enhancement Percentage to Saline) was shown 641.1, -90.0, 127.3, 527% at iodine and 685.1, 99.4, 365.7, 1077.4% was recorded at gadolinium. BP(BDEPS's point) was shown 900, 900, 477, 900 mmol at iodine and 4, 0.2, 0.2, 40 mmol was recorded at gadolinium. CPSS(Change Point of SI to SSI) was shown 63, 423, 63, 29 mmol at iodine and each [50, 30], [4, 0.2], [4, 1], 0.2 mmol was recorded at gadolinium. According to this research, we could not only discover the fact that was iodine could effect on MR signal, but also the pattern is different as various sequences compare to gadolinium. Therefore, we expect useful diagnostic MR image in clinical field with this quantitative data for deciding protocol regarding MRI and CT scan order.

• Journal of Veterinary Clinics
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• v.26 no.1
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• pp.104-108
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• 2009

Global cerebral ischemia occurs commonly in patients who have a variety of clinical conditions including cardiac arrest and shock. Cerebral ischemia results in a rapid depletion of energy stores that triggers resulting in excitotoxic death. Imaging studies of the brain with computed tomography(CT) or magnetic resonance imaging(MRI) are necessary to confirm the clinical neurolocalization, identify any associated mass effect, and rule out other causes of focal brain disorders. Cardiopulmonary arrest was occurred by propofol anesthesia in a 1 year old, intact female Beagle dog. After successful cardiopulmonary resuscitation was performed within 5 minutes, clinical signs such as vocalization, paddling, opisthotonus and seizure were represented. At the 12th day, CT and MRI examinations of the brain were performed to evaluate the brain. After euthanasia, histopathologic examination was performed. On transverse image of CT, lesions appeared as a hypodense in the right dorsal surface of the frontal lobe and level of optic canal, and dorsomedial surface of occipital lobe of cerebrum. No contrast enhancement was represented following intravenous contrast administration. On MR images of brain, the lesions were seen as a hyperintense on T2-weighted(T2W) images and a isointense or mild hypointense on T1-weighted(T1W) images. Hyperintense lesions both T2W and T1W images were observed at the surrounding cerebral sulcus. There was no significant signal changes on contrast T1WI. Histopathologic examination after euthanasia revealed that the lesion was necrosis of the cerebral cortex caused by cerebral ischemia.

• Nuclear Engineering and Technology
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• v.56 no.5
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• pp.1803-1812
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• 2024

The attractive properties of gadolinium-based nanoparticles as a positive contrast agent for magnetic resonance imaging (MRI) have piqued the interest of both researchers and clinicians. Nonetheless, due to the biotoxicity of gadolinium (III) ions' free radicals, there is a need to address this issue. Therefore, this research aimed to develop a biocompatible, dispersible, stable, hydrophilic, and less toxic cellulose nanocrystals/gadolinium oxide nanocomposite as contrast agent properties for MRI purposes. This study aimed to synthesize gadolinium oxide nanoparticles coated with cellulose nanocrystals with polyethylene glycol and sodium hydroxide (CNCs-PEG/NaOH)/Gd₂O₃ using the gamma irradiation method to reduce the particle size. The results showed that using a gamma irradiation dose of 10 kGy, quasi-spherical morphology with a size of approximately 5.5 ± 0.65 nm could be produced. Furthermore, the cytocompatibility of (CNCs-PEG/NaOH)/Gd₂O₃ nanocomposite synthesized was assessed through MTT assay tests on Hep G2 cells, which demonstrated good cytocompatibility without any cytotoxic effects within a concentration range of (10 ㎍/mL - 150 ㎍/mL) and had sufficient cellular uptake. Moreover, the T₁-weighted MRI of (CNCs-PEG/NaOH)/Gd₂O₃ nanocomposite revealed promising results as a positive contrast agent. It is envisaged that the gamma irradiation method is promising in synthesizing (CNCs-PEG/NaOH)/Gd₂O₃ nanocomposite with nanoscale for different applications, especially in the radiotherapy field.

• Investigative Magnetic Resonance Imaging
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• v.6 no.1
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• pp.35-40
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• 2002

Purpose : To evaluate the NMR relaxation properties and imaging characteristics of tissue-specificity for a newly developed macromolecular MR agent. Materials and methods : Phthalocyanine (PC) was chelated with paramagnetic ion, Mn.2.01g (5.2 mmol) of Phthalocyanine was mixed with 0.37g (1.4 mmol) of Mn chloride at $310^{\circ}C$ for 36 hours and then purified by chromatography (CHC13/CH3OH 98/2 v/v, Rf, 0.76) to obtain 1.04g (46%) of MnPC (molecular weight= 2000d). The $T1}T2$ relaxivity of MnPC was measured in 1.5T(64 MHz) MR using 0.1 mM MnPC. The MR image characteristics of MnPC was evaluated using spin-echo (TR/TE=500/14 msec) and gradient-echo (FLASH) (TR/TE=80/4 msec, flip angle=60) techniques in 1.57 MR scanner. The images of rabbit liver were obtained every 10 minutes up to 4 hours. To study the effect of concentration on image, 20 mM, 50 mM, 100 mM of MnPC were tested. Results : The relaxivities of MnPC at 1.5T(64MHz) were Rl=7.28 $mM^{-1}S^{-1},{\;}R2=55.56mM^{-1}S^{-1}$. Compared to the values of Gd-DTPA (Rl[=4.8 $mM^{-1}S^{-1})$], R2[=5.2 $mM^{-1}S^{-1}])$]), both T1/T2 relaxivities of MnPC were higher than those of Gd-DTPA. For both of SE and FLASH techniques, the contrast enhancement reached maximum at 10 minutes after bolus injection and the enhancement continued for more than 2 hours. When compared with small molecular weight liver agents such as Gd-EOB-DTPA, Gd-BOPTA and MnDPDP, MnPC was characterized by more prolonged enhancement time. The time course of MR images also revealed biliary excretion of MnPC. Conclusion : We developed a new macromolecular MR agent, MnPC. The relaxivities of MnPC were higher than those of small molecular weight Gd-chelate. Hepatic uptake and biliary excretion of MnPC suggests that this agent is a new liver-specific MR agent.

• Korean Journal of Radiology
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• v.22 no.9
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• pp.1514-1524
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• 2021

Objective: To develop a radiomics risk score based on dynamic contrast-enhanced (DCE) MRI for prognosis prediction in patients with glioblastoma. Materials and Methods: One hundred and fifty patients (92 male [61.3%]; mean age ± standard deviation, 60.5 ± 13.5 years) with glioblastoma who underwent preoperative MRI were enrolled in the study. Six hundred and forty-two radiomic features were extracted from volume transfer constant (K^trans), fractional volume of vascular plasma space (V_p), and fractional volume of extravascular extracellular space (V_e) maps of DCE MRI, wherein the regions of interest were based on both T1-weighted contrast-enhancing areas and non-enhancing T2 hyperintense areas. Using feature selection algorithms, salient radiomic features were selected from the 642 features. Next, a radiomics risk score was developed using a weighted combination of the selected features in the discovery set (n = 105); the risk score was validated in the validation set (n = 45) by investigating the difference in prognosis between the "radiomics risk score" groups. Finally, multivariable Cox regression analysis for progression-free survival was performed using the radiomics risk score and clinical variables as covariates. Results: 16 radiomic features obtained from non-enhancing T2 hyperintense areas were selected among the 642 features identified. The radiomics risk score was used to stratify high- and low-risk groups in both the discovery and validation sets (both p < 0.001 by the log-rank test). The radiomics risk score and presence of isocitrate dehydrogenase (IDH) mutation showed independent associations with progression-free survival in opposite directions (hazard ratio, 3.56; p = 0.004 and hazard ratio, 0.34; p = 0.022, respectively). Conclusion: We developed and validated the "radiomics risk score" from the features of DCE MRI based on non-enhancing T2 hyperintense areas for risk stratification of patients with glioblastoma. It was associated with progression-free survival independently of IDH mutation status.