• Clinical Endoscopy
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• v.56 no.2
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• pp.229-238
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• 2023

Background/Aims: Shear wave elastography (SWE) is used for liver fibrosis staging based on stiffness measurements. It can be performed using endoscopic ultrasound (EUS) or a transabdominal approach. Transabdominal accuracy can be limited in patients with obesity because of the thick abdomen. Theoretically, EUS-SWE overcomes this limitation by internally assessing the liver. We aimed to define the optimal technique for EUS-SWE for future research and clinical use and compare its accuracy with that of transabdominal SWE. Methods: Benchtop study: A standardized phantom model was used. The compared variables included the region of interest (ROI) size, depth, and orientation and transducer pressure. Porcine study: Phantom models with varying stiffness values were surgically implanted between the hepatic lobes. Results: For EUS-SWE, a larger ROI size of 1.5 cm and a smaller ROI depth of 1 cm demonstrated a significantly higher accuracy. For transabdominal SWE, the ROI size was nonadjustable, and the optimal ROI depth ranged from 2 to 4 cm. The transducer pressure and ROI orientation did not significantly affect the accuracy. There were no significant differences in the accuracy between transabdominal SWE and EUS-SWE in the animal model. The variability among the operators was more pronounced for the higher stiffness values. Small lesion measurements were accurate only when the ROI was entirely situated within the lesion. Conclusions: We defined the optimal viewing windows for EUS-SWE and transabdominal SWE. The accuracy was comparable in the non-obese porcine model. EUS-SWE may have a higher utility for evaluating small lesions than transabdominal SWE.

• Progress in Medical Physics
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• v.21 no.4
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• pp.348-353
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• 2010

The purpose of this study was to explore the potentials of a clinical 3T MRI in mouse brains and technical adaptation and optimization. T1-weighted images (T1WI), T2-weighted images (T2WI), FLAIR (Fluid Attenuated Inversion Recovery) images, Gadolinium enhanced T1-weighted images (Gd-T1WI), Diffusion weighted images (DWI) were acquired in brain of 2 mice (weight 20~25 g) with cerebral infarction by occlusion of right middle cerebral artery, 1 hour, 24 hours, 72 hours after infarction and 1 normal mouse brain using clinical 3T MRI scanner. We analyzed differentiation of striatum, ventricle, cerebral cortex, and possibility of detection of acute cerebral infarction. We could differentiate the striatum, ventricle, cerebral cortex on T2WI and on DWI, FLAIR, T1WI, the differentiation of each anatomy of brain was not definite, but acute cerebral infarction was detected on DWI of 1 hour, 24 hours, 72 hours after infarction and on T2WI, FLAIR of 24 hours, 72 hours after infarction. Clinical 3T MRI can be used in differentiation of anatomy of mouse brains and DWI can be helpul in detection of acute cerebral infarction in acute phase. With technical adaptation and optimization clinical 3T MRI can be useful tool for provide preclinical and clinical small animal studies.

• Journal of Veterinary Clinics
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• v.30 no.1
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• pp.32-35
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• 2013

Six English Bull dogs from the same dog training camp were referred with main complaints of stridor, gagging and coughing. Diagnostic imaging studies on these dogs revealed hypoplastic trachea with/without bronchopneumonia. The mean age of affected dogs was $4.83{\pm}2.63$ months, while the mean body weight was $9.03{\pm}5.30$ kg. The mean ratio of the tracheal diameter to the thoracic inlet distance (TD/TI) was $0.085{\pm}0.022$ (normally 0.16 or greater), whereas the mean ratio tracheal diameter to the width of the third rib (TD/W3R) was $1.36{\pm}0.36$ (normally 2 or greater). All dogs had marked inspiratory dyspnea with variable degree of coughing. Of 6 dogs, 4 dogs had either bronchitis or bronchopneumonia. Treatment with antibiotics and bronchodilators made improvement on clinical signs on these dogs. Although some dogs still had mild inspiratory dyspnea (especially after exercise or excitement), most dogs live normally.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.2 no.2
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• pp.113-117
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• 2016

As a neurotransmitter, serotonin plays important roles in brain. It relates various neuropsychiatric disorders such as anxiety, depression, schizophrenia. [$^{11}C$]DASB is a well-known PET tracer for serotonin transporter imaging. In this study, we synthesized [$^{11}C$]DASB in HPLC loop for simple and rapid production. Total synthesis time was about 40 minutes and the radiochemical purities were over 99%. The specific activity was $51.4GBq/{\mu}mole$ (n=16). [$^{11}C$]DASB showed highest uptake in mid-brain that serotonergic nerves are abundant and lowest uptake in cerebellum. In conclusion, we used HPLC loop method for [$^{11}C$]DASB labeling and this method is useful for production of $^{11}C$ labeled PET tracers.

• Journal of Veterinary Clinics
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• v.28 no.4
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• pp.408-414
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• 2011

This study was carried out to analyze the utilization of ultrasound machines in animal hospitals and focused on surveying the present condition of diagnostic ultrasound on veterinary medicine in South Korea. Total 279 veterinary hospitals were surveyed with e-mail questionnaires or telephone survey. E-mail questionnaires consist of 17 items of questions including existence of ultrasound machine, types of ultrasound machine, ultrasound examination costs, frequency, purposes, other diagnostic imaging equipments, and referring system of ultrasound. Telephone surveys asked about the existence of the ultrasound machine and types of the ultrasound machine to 279 animal hospitals. Two hundred and seventy-one out of 279 animal hospitals holds ultrasound machine. Seventy-two percents clinics purchased used ultrasonographic machines and mean years after the date of manufacture is 7.5 years and the proportion of superannuated machines are relatively high. Also many clinicians prefer single organ scanning rather than general scan technique and more than 60% of clinics perform ultrasonographic examination less than 5 times a week. Clinics located in Seoul area tend to have more expensive and brand-new ultrasonographic machines and the distribution of radiology specialist are higher in this area. Problems associated with the present condition were oversupply of machines, unequal distribution of the medical equipment in different localities, ineffective use of the medical equipment, and high percentage of old poor-quality medical equipments. There should be a viable alternative proposal to control amount and quality of the ultrasound machines. Also, the improved management system for the ultrasound machine is required.

• Journal of Veterinary Clinics
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• v.32 no.3
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• pp.243-246
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• 2015

A 9 month-old female Chihuahua (weighing 1.5 kg) was referred with loud left basal murmur and exercise intolerance. Diagnostic imaging studies revealed the elongation of left ventricle (LV) with classic triple bumps on the main pulmonary artery, aorta and left atrium on the dorsoventral view of radiograph. Echocardiography revealed patent ductus arteriosus (PDA) duct and continuous turbulent shunt flow (maximal velocity 5.73 m/s) between the aorta and pulmonary artery with left to right direction. The PDA in this dog was successfully closed though femoral vein (transvenous approach) using an Amplatzer$^{(R)}$ vascular plug. To the best of author's knowledge, this is the first case of PDA occlusion treated with vascular plug through femoral vein.

• Journal of Veterinary Clinics
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• v.30 no.4
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• pp.320-323
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• 2013

Spinal cord infarction is becoming recognized as an important cause of acute myelopathy in cats. Although the definitive diagnosis is confirmed through postmortem histopathologic examination, MR imaging features provide valuable informations for the diagnosis of spinal cord infarction. The aim of this report is to describe MR findings of acute spinal cord infarction in two cats and to evaluate usefulness of low field MRI (0.3Tesla) as a potential diagnostic tool of acute spinal cord infarction. A cat (unknown age, neutered male mixed breed cat) was referred one day after the acute onset of non-ambulatory spastic tetraparesis and the other cat (a 9-year-old, neutered female domestic short hair cat) was presented due to the acute onset of non-ambulatory paraparesis and one day later paraplegia. The lesions of the MR images were shown on the spinal cord parenchyma over C2 to C6 in case 1 and L2 to L5 in case 2. The MR images in these two cases were characterized by focal intramedullary lesions, mainly involving grey matter which were hyperintense T2 weighted and FLAIR images and hyperintense on DWI and hypointense on ADC map. The MR findings in both cases were highly suggestive of acute spinal cord infarctions, based upon previous reported small animal cases and human cases. In conclusion, based on MR features, together with the history and clinical examination findings, MRI modality can be used as an antemortem tool for the diagnosis of acute spinal cord infarction in cats.

• Journal of the Korean Physical Society
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• v.73 no.11
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• pp.1764-1773
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• 2018

A-PET is a quad-head PET scanner developed for use in small-animal imaging. The dimensions of its volumetric field of view (FOV) are $46.1{\times}46.1{\times}46.1mm^3$ and the gap between the detector modules has been minimized in order to provide a highly sensitive system. However, such a small FOV together with the quad-head geometry causes image quality degradation. The main factor related to image degradation for the quad-head PET is the mispositioning of events caused by the penetration effect in the detector. In this paper, we propose a precise method for modelling the system at the high spatial resolution of the A-PET using a LOR (line of response) based ML-EM (maximum likelihood expectation maximization) that allows for penetration effects. The proposed system model provides the detection probability of every possible ray-path via crystal sampling methods. For the ray-path sampling, the sub-LORs are defined by connecting the sampling points of the crystal pair. We incorporate the detection probability of each sub-LOR into the model by calculating the penetration effect. For comparison, we used a standard LOR-based model and a Monte Carlo-based modeling approach, and evaluated the reconstructed images using both the National Electrical Manufacturers Association NU 4-2008 standards and the Geant4 Application for Tomographic Emission simulation toolkit (GATE). An average full width at half maximum (FWHM) at different locations of 1.77 mm and 1.79 mm are obtained using the proposed system model and standard LOR system model, which does not include penetration effects, respectively. The standard deviation of the uniform region in the NEMA image quality phantom is 2.14% for the proposed method and 14.3% for the LOR system model, indicating that the proposed model out-performs the standard LOR-based model.

• Journal of Veterinary Clinics
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• v.32 no.1
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• pp.49-55
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• 2015

This study was retrospectively investigated the clinical features, diagnostic imaging, treatment, and prognosis of foreign bodies according to alimentary site and type of foreign body, in 143 dogs. Among 28 breeds, Maltese, Shih Tzu, and terriers including the Yorkshire terrier were presented with high prevalence. Bone was the most commonly identified (33%) foreign body regardless of alimentary site. Approximately 76% of foreign bodies were in the stomach and small intestine. All esophageal foreign bodies were diagnosed on survey radiography, with the most common location being the caudal thoracic esophageal segment. Further diagnostic examinations including ultrasonography or contrast studies were additionally performed to detect radiolucent foreign bodies and perforation or leakage in the stomach and intestine. However, most seeds could be identified based on the characteristic features such as hyperdense thin double lines and inner gas on survey radiography. In conclusion, complications such as peritonitis and intestinal perforation were mainly observed in cases with seeds and linear foreign bodies. Especially, fabric foreign bodies could be induce peritonitis and re-perforation with high prevalence after surgical correction.

• Journal of Veterinary Clinics
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• v.36 no.5
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• pp.278-281
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• 2019

A 12-year-old castrated male Maltese dog was presented with a small-sized mass at the left fifth mammary gland. The dog had concurrent poorly responsive pruritus affecting the feet, pinnae, and trunk, a cystolith, and biliary sludge. Serum chemistry revealed elevated liver enzymes. The mammary gland mass was cytologically diagnosed as an early-stage mammary simple carcinoma and was surgically excised. Nine months after the diagnosis of the mammary carcinoma, hyperadrenocorticism was confirmed by adrenocorticotropic hormone stimulation test. This report describes the clinical signs, diagnostic imaging findings, and prognosis in a castrated male Maltese dog with mammary carcinoma.