• Journal of Korean Neurosurgical Society
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• v.50 no.5
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• pp.472-474
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• 2011

Cortical laminar necrosis appears as hyperinense lesions with a laminar pattern on T1 weighted magnetic resonance (MR) imaging, without signs of hemorrhage or calcification on T2 weighted MR imaging or computed tomography. It has been reported to be associated with hypoxia, metabolic disturbances, drugs, and infections. We present a 12 month-old male infant who suffered diffuse brain injuries following car accident and showed laminar necrosis of cortex.

• Korean Journal of Radiology
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• v.25 no.9
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• pp.843-850
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• 2024

Radiation recall pneumonitis is an inflammatory reaction of previously radiated lung parenchyma triggered by systemic pharmacological agents (such as chemotherapy and immunotherapy) or vaccination. Patients present with non-specific symptoms such as cough, shortness of breath, or hypoxia soon after the initiation of medication or vaccination. Careful assessment of the patient's history, including the thoracic radiation treatment plan and timing of the initiation of the triggering agent, in conjunction with CT findings, contribute to the diagnosis. Once a diagnosis is established, treatment includes cessation of the causative medication and/or initiation of steroid therapy. Differentiating this relatively rare entity from other common post-therapeutic complications in oncology patients, such as recurrent malignancy, infection, or medication-induced pneumonitis, is essential for guiding downstream clinical management.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.1 no.2
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• pp.123-129
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• 2015

$^{64}Cu$-labeled diacetyl-bis($N^4$-methylthiosemicarbazone) is a promising agent for internal radiation therapy and imaging of hypoxic tissues. In the study, we confirmed hypoxia regions in VX2 tumor implanted rabbits with injection $^{64}Cu$-ATSM and $^{18}F$-FDG using positron emission tomography (PET)/computed tomography (CT). PET images with $^{18}F$-FDG and $^{64}Cu$-ATSM were obtained for 40 min by dynamic scan and additional delayed PET images of $^{64}Cu$-ATSM the acquired up to 48 hours. Correlation between intratumoral $O_2$ level and $^{64}Cu$-ATSM PET image was analyzed. $^{64}Cu$-ATSM and $^{18}F$-FDG were intravenously co-injected and the tumor was dissected and cut into slices for a dual-tracer autoradiographic analysis. In the PET imaging, $^{64}Cu$-ATSM in VX2 tumors displayed a specific uptake in hypoxic region for48 h. The uptake pattern of $^{64}Cu$-ATSM in VX2 tumor at 24 and 48 h did not match to the $^{18}F$-FDG. Through ROI analysis, in the early phase (dynamic scan), $^{18}F$-FDG has positive correlation with $^{64}Cu$-ATSM but late phase (24 and 48 h) of the $^{64}Cu$-ATSM showed negative correlation with $^{18}F$-FDG. High uptake of $^{64}Cu$-ATSM in hypoxic region was responded with significant decrease of oxygen pressure, which confirmed by $^{64}Cu$-ATSM PET imaging and autoradiographic analysis. In conclusion, $^{64}Cu$-ATSM can utilize for specific targeting of hypoxic region in tumor, and discrimination between necrotic- and viable hypoxic tissue.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.9 no.2
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• pp.101-105
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• 2023

Cu(II) diacetyl-di(N⁴-methylthiosemicarbazone), also known as Cu(II)-ATSM, is a popular copper-complexed thiosemicarbazone derivative that has been widely studied for hypoxia. [⁶⁴Cu]Cu-ATSM has emerged as an effective tracer for positron emission tomography imaging to functionally characterize hypoxic tumors. However, understanding the precise mechanism of cellular uptake and metabolism of Cu(II)-ATSM remains a controversial task in which different hypotheses have been proposed. Herein, we will elucidate the current findings regarding the hypoxic uptake mechanism of Cu(II)-ATSM. Particularly, we will investigate the cell internalization mechanism and intracellular reduction of Cu(II)-ATSM.

• Proceedings of the Optical Society of Korea Conference
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• 2006.02a
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• pp.359-360
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• 2006

Functional photoacoustic tomography is a new non-invasive imaging modality, and it is emerging as a very practical method for imaging biological tissue structures by means of laser-induced ultrasound. Structures with high optical absorption, such as blood vessels, can be imaged with the spatial resolution of ultrasound, which is not limited by the strong light scattering in biological tissues. By varying wavelengths of the laser light and acquiring photoacoustic images, optical absorption spectrum of each image pixel is found. Since the biochemical constituents of tissues determine the spectrum, useful functional information like oxygen saturation ($SO_2$) and total haemoglobin concentration (HbT) can be extracted. In this study, as a proof-of-principle experiment, hypoxic brain tumor vasculature and traumatic brain injury (TBI) of small animal brain are imaged with functional photoacoustic tomography. High resolution brain vasculature images of oxygen saturation and total hemoglobin concentration are provided to visualize hypoxic tumor vasculature, and hemorrhage on the cortex surface by the TBI.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.5 no.1
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• pp.18-25
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• 2019

2-Nitroimidazole derivatives have been reported to accumulate in hypoxic tissue. We prepared a novel $^{99m}Tc-MAG_3$-2-nitroimidazole and evaluated the feasibility for hypoxia imaging agent. $Bz-MAG_3$-2-nitroimidazole was synthesized by direct coupling of $Bz-MAG_3$ and 2-nitroimidazole using dicyclohexylcarbodiimide. $Bz-MAG_3$-2-nitroimidazole was labeled with $^{99m}Tc$ in the presence of tartaric acid and $SnCl_2-2H_2O$ at $100^{\circ}C$ for 30 min. And the reaction mixture was purified by $C_{18}$ Sep-pak cartridge. The labeling efficiency and the radiochemical purity were checked by ITLC-SG/acetonitrile. The tumor was grown in balb/c mice for 8~13 days after the subcutaneous injection of tumor cells, CT-26 (murine colon adenocarcinoma cell). Biodistribution study and tumor autoradiography were performed in the xenografted mice after i.v injection of 74 kBq/0.1 mL and 19 MBq/0.1 mL of $^{99m}Tc-MAG_3$-2-nitroimidazole, respectively. In vivo images of $^{99m}Tc-MAG_3$-2-nitroimidazole in tumor bearing mice were obtained 1.5 hr post injection. The labeling efficiency was $45{\pm}20%$ and the radiochemical purity after purification was over 95%. Paper electrophoresis confirmed negative charge of $^{99m}Tc-MAG_3$-2-nitroimidazole. $^{99m}Tc-MAG_3$-2-nitroimidazole was very stable at room temperature and its protein binding was 53%. The $^{99m}Tc-MAG_3$-2-nitroimidazole exhibited high uptake in the liver, stomach and intestine. In biodistribution study using tumor bearing mice, the uptakes (% ID/g) of the tumor were $0.5{\pm}0.1$, $0.4{\pm}0.0$, $0.2{\pm}0.1$ and $0.1{\pm}0.1$ at 5, 15, 30 min and 4 hrs. Tumor/muscle ratio were $1.4{\pm}0.1$, $2.2{\pm}0.83$, $3.0{\pm}0.9$, and 3.7 (n=2) for 5, 15, 30 min and 4 hrs. The uptake in hypoxic area was found higher than in non-hypoxic area of tumor tissue by autoradiography. In vivo images showed the relatively faint uptake to the hypoxic tumor region. $^{99m}Tc-MAG_3$-2-nitroimidazole was successfully synthesized and found feasible for imaging hypoxia.

• Korean Journal of Radiology
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• v.20 no.5
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• pp.830-843
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• 2019

Objective: To examine the potential of intravoxel incoherent motion (IVIM) and blood oxygen level-dependent (BOLD) magnetic resonance imaging for detecting renal changes after iodinated contrast-induced acute kidney injury (CI-AKI) development in a diabetic rabbit model. Materials and Methods: Sixty-two rabbits were randomized into 2 groups: diabetic rabbits with the contrast agent (DCA) and healthy rabbits with the contrast agent (NCA). In each group, 6 rabbits underwent IVIM and BOLD imaging at 1 hour, 1 day, 2 days, 3 days, and 4 days after an iohexol injection while 5 rabbits were selected to undergo blood and histological examinations at these specific time points. Iohexol was administrated at a dose of 2.5 g I/kg of body weight. Further, the apparent transverse relaxation rate (R2^*), average pure molecular diffusion coefficient (D), pseudo-diffusion coefficient (D^*), perfusion fraction (f) were calculated. Results: The D and f values of the renal cortex (CO) and outer medulla (OM) were significantly decreased compared to baseline values in the 2 groups 1 day after the iohexol injection (p < 0.05). A marked reduction in the D^* values for both the CO and OM was also observed after 1 hour in each group (p < 0.05). In the OM, a persistent elevation of the R2^* was detected for 4 days in the DCA group (p < 0.05). Histopathological changes were prominent, and the pathological features of CI-AKI aggravated in the DCA group until day 4. The D, f, and R2^* values significantly correlated with the histological damage scores, hypoxia-inducible transcription factor-1α expression scores, and serum creatinine levels. Conclusion: A combination of IVIM and BOLD imaging may serve as a noninvasive method for detecting and monitoring CI-AKI in the early stages in the diabetic kidney.

• The Korean Journal of Nuclear Medicine
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• v.33 no.3
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• pp.289-297
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• 1999

Purpose: Misonidazole is a radiosensitizer that binds in hypoxic cells. The purpose of this study was to find out the feasibility of I-131-Iodomisonidazole (IMISO) for imaging of tumor hypoxia. Materials and Methods: Tosyl precursor was dissolved in acetonitrile and I-131-NaI was added to synthesize IMISO. Balb/c mice inoculated with CT-26 adenocarcinoma were injected with IMISO. Mice were sacrificed at 1, 2, 4, 24 hr and % of injected dose per gram of tissue (%ID/g) was determined. For scintigraphy and MRI, mouse bearing CT-26 adenocarcinoma was administered with IMISO and imaging was performed 4 hr after. Then, mouse body was fixed and microtomized slice was placed on radiographic film for autoradiography Results: %ID/g of tumor was 1.64 (1h), 0.98 (2h), 0.85 (4h) and 0.20 (24h), respectively. At 24h, %ID/g of tumor was higher than that of all other tissues except thyroid. Tumor to muscle ratio increased with time and tumor to blood ratio also increased with time and reached 1.53 at 24 hr. On autoradiogram, tumor was well visualized as an increased activity in central hypoxic area of the tumor which corresponds to the area of high signal intensity on T2-weighted MR image. On scintigraphy, tumor uptake was visualized. Conclusion: This results suggest that IMISO may have a potential for tumor hypoxia imaging in mouse model. However, further study is needed to improve it's localization in tumor tissue and to achieve acceptable images of tumor hypoxia.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.9 no.2
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• pp.81-85
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• 2023

Hydrogen sulfide (H₂S), recognized as the third gasotransmitter with specific implications for inflammation and hypoxia, exhibits affinity for ⁶⁴Cu immobilization. This study explores the viability of ⁶⁴Cu-labeled PET tracers in detecting endogenous H₂S. In vitro reactivity experiments involved evaluating the interaction between various concentrations of NaHS and ⁶⁴Cu-labeled chelators at 37℃ in a shaking incubator. In vivo molecular PET imaging studies were conducted using two distinct mouse models. An acute inflammation model, induced with carrageenan, involved administering 2.22 MBq/100 µL of [⁶⁴Cu]Cu-ATSM or [⁶⁴Cu]Cu-Cyclen intravenously 4 hours post-inflammation induction, with subsequent PET imaging in static 5 min mode. For the NaHS implantation model, NaHS dissolved in Matrigel was subcutaneously injected into the right dorsal region of BALB/c mice, followed by intravenous injection of radiotracers (2.22 MBq/100 µL) 1 hour later, and subsequent PET imaging. The optimized labeling condition involved dissolving 10 ㎍ of chelators in ammonium acetate buffer and reacting at 60℃ for 20 minutes. Both [⁶⁴Cu]Cu-Cyclen and [⁶⁴Cu]Cu-ATSM reacted with various concentrations of NaHS to form insoluble ⁶⁴CuS. High uptake of [⁶⁴Cu]Cu-ATSM and [⁶⁴Cu]Cu-Cyclen in acute inflammatory lesions in the mouse right footpad and the NaHS implantation model suggests their potential as imaging agents for inflammation and H₂S in vivo. In conclusion, optimized [⁶⁴Cu]Cu-ATSM and [⁶⁴Cu]Cu-Cyclen labeling conditions for endogenous H₂S imaging were established, confirming insoluble ⁶⁴CuS both in vitro and in vivo. [⁶⁴Cu]Cu-ATSM and [⁶⁴Cu]Cu-Cyclen hold promise as diagnostic agents targeting endogenous H₂S in various diseases associated with inflammation and hypoxia.

• Advances in pediatric surgery
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• v.1 no.2
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• pp.204-208
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• 1995

Neonatal adrenal hemorrhage is frequently associated with birth trauma or perinatal hypoxia. Hemorrhagic necrosis of the adrenal glands is often found at autopsy and many small lesions are usually asymptomatic. A palpable abdominal mass and jaundice are the usual presenting signs. Ultrasound is very useful in the diagnosis of this lesion; however, if the mass has mixed echoic pattern, magnetic resonance imaging (MRl) is helpful for the differential diagnosis from neuroblastoma. We present the case of a female newborn who was found to have a abdominal mass on physical examination. The patient showed anemia and hyperbilirubinemia. An ultrasonogram disclosed a $3.8{\times}3.0$ cm suprarenal mass with mixed echoic pattern. The mass was initially suspected to be neuroblastoma. An abdominal computed tomogram was not able to differentiate the mass. Magnetic resonance imaging revealed markedly increased signal intensity on T1 and T2-weighted sequences. This finding was consistent with adrenal hemorrhage. Serial sonogram demonstrated the mass that resolved completely by 12 weeks of age.