Junghee Yoon

Seoul National University, Sŏul, Seoul, South Korea

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Publications (51)55.76 Total impact

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    ABSTRACT: Differentiating hepatocellular disease versus biliary obstruction can be challenging in dogs presented for icterus. The purpose of this prospective study was to determine the feasibility of percutaneous contrast ultrasound-guided cholecystography in dogs. Ten normal dogs weighing 7.6–13.0 kg (median 9.8 kg) were recruited. All dogs were considered normal based on complete blood count, serum chemistry profile, ultrasound examination, and percutaneous radiographic cholecystography. Percutaneous contrast ultrasound-guided cholecystography was performed using 0.5 ml of commercially available contrast agent and two conventional ultrasound machines for simultaneous scanning at two different locations. Two observers independently evaluated the time to initial detection of contrast in the proximal duodenum and duration of contrast enhancement via visual monitoring. Dynamic contrast enhancement was calculated using time-intensity curves. Mean (±SD) and median (range) of time to initial detection were 8.60 s (± 3.35) and 8.0 s (2.0–11.0), respectively, and mean and median duration were 50.45 s (±23.24) and 53.0 s (20.0 – 70.0), respectively. Mean, median, and range of peak intensity were 114.1 mean pixel value (MPV) (SD ± 30.7), 109.2 MPV, and 79.7–166.7, respectively, and mean, median, and range of time to peak intensity were 26.1 s (SD ± 7.1 s), 24.0 s, and 19.0–41.0 s, respectively. Findings indicated that percutaneous contrast ultrasound-guided cholecystography is a feasible technique for detecting and quantifying patency of the bile duct in normal dogs. Future studies are needed to assess the diagnostic utility of this technique for dogs with biliary obstruction.
    Veterinary Radiology &amp Ultrasound 11/2014; · 1.41 Impact Factor
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    ABSTRACT: To evaluate the volume effect of local anesthetic solution on thoracic epidural analgesia in dogs.
    Veterinary Anaesthesia and Analgesia 10/2014; · 1.34 Impact Factor
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    ABSTRACT: Objective This study was performed to evaluate the relationship between cataract and vitreous degeneration on ultrasonography (VDU) in dogs.Materials and methodsMedical records of dogs were retrospectively reviewed. The dogs presented at the Veterinary Medical Teaching Hospital of Seoul National University from January 2009 to December 2011 for ocular ultrasonography to investigate the suitability of the patient for cataract surgery. A total of 97 dogs (179 eyes) were included in this study. Data collected included age, gender, ophthalmic examination, and ultrasonographic examination. Cataract was classified into five grades by ophthalmic examination (0: normal, 1: incipient, 2: immature, 3: mature, and 4: hypermature). VDU was classified into 4 grades (0: no degeneration, 1: mild vitreous degeneration, 2: moderate vitreous degeneration, and 3: marked vitreous degeneration).ResultsThe mean rank of VDU grades increased with the progression of cataracts, and statistical significant differences were shown between cataracts grade 0 and 2 (P = 0.010), between 0 and 3 (P < 0.001), between 0 and 4 (P = 0.010), between 1 and 3 (P = 0.03), between 1 and 4 (P = 0.02), and between 2 and 4 (P = 0.04). There were no significant differences in age and gender according to the cataract grades. There was no statistical significant difference in the mean rank of VDU grades between cataractous eyes with lens-induced uveitis (LIU) and those without LIU.Conclusions The results indicated that increased VDU was associated with more severe cataract grades in dogs.
    Veterinary Ophthalmology 10/2014; · 0.96 Impact Factor
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    ABSTRACT: An 8-month-old cat was presented with bilateral hydronephrosis. Bilateral ureteral obstructions were identified by diagnostic imaging and confirmed by necropsy. Histopathologic findings revealed polypoid transitional epithelial hyperplasia with chronic lymphoplasmacytic inflammation. This report documents congenital ureteral strictures as a cause of ureteral obstruction in a young cat.
    The Canadian veterinary journal. La revue vétérinaire canadienne. 09/2014; 55(9):841-4.
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    ABSTRACT: A 10-year-old castrated Shih-Tzu male dog was referred for examination of acute right exophthalmos, protrusion of the third eyelid and soft tissue swelling ventral to the globe. Ultrasonography revealed echogenic fluid around the right globe. Computed tomography (CT) showed an enlarged right zygomatic salivary gland compared with the left zygomatic gland and an amorphous cystic mass ventral to the right globe. Hyperattenuated material, which we suspected to be a sialolith, was identified in the right zygomatic gland. The zygomatic gland and the cystic lesion were removed, and a zygomatic sialocele with sialolith and ductal obstruction were found by histopathological examination. CT was a useful diagnostic tool for zygomatic sialolithiasis.
    Journal of Veterinary Medical Science 06/2014; · 0.88 Impact Factor
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    ABSTRACT: Diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) are functional magnetic resonance (MR) imaging techniques that detect the water diffusion. DWI and ADC were applied to the intracranial lesions in two dogs with non-infectious inflammatory disease and brain tumor using low field magnet. Cavitated lesions showed hypointense center with hyperintense periphery on DWI and hyperintense signal on ADC maps in necrotizing leukoencephalitis case. In metastatic sarcoma case, masses including necrotic region showed hypointense on DWI and hyperintense on ADC map with perilesional edema characterized by high signal on DWI and ADC map. As DWI and ADC depend on the altered molecular motion of water by pathologic condition, it is considered that they could provide additional information at molecular level for lesions.
    Journal of veterinary science (Suwŏn-si, Korea) 03/2014; · 0.89 Impact Factor
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    ABSTRACT: Objective To determine the effect of injection speed on epidural pressure (EP), injection pressure (IP), epidural distribution (ED) of solution, and extent of sensory blockade (SB) during lumbosacral epidural anesthesia in dogs.Study designProspective experimental trial.AnimalsTen healthy adult Beagle dogs weighing 8.7 ± 1.6 kg.Methods General anesthesia was induced with propofol administered intravenously and maintained with isoflurane. Keeping the dogs in sternal recumbency, two spinal needles connected to electrical pressure transducers were inserted into the L6-L7 and the L7-S1 intervertebral epidural spaces for EP and IP measurements, respectively. Bupivacaine 0.5% diluted in iohexol was administered epidurally to each dog via spinal needle at L7-S1 intervertebral space, at two rates of injection (1 and 2 mL minute−1 groups), with a 1-week washout period. Epidural distribution was verified with computed tomography, and SB was evaluated after arousal by pinching the skin with a mosquito hemostatic forceps over the vertebral dermatomes. The results were analyzed according to each injection speed, using paired t- and Wilcoxon signed-rank tests.ResultsMean ± SD of baseline EP and IP values were 2.1 ± 6.1 and 2.6 ± 7.1 mmHg, respectively. Significant differences were observed between 1 and 2 mL minute−1 groups for peak EP (23.1 ± 8.5 and 35.0 ± 14.5 mmHg, p = 0.047) and peak IP (68.5 ± 10.7 and 144.7 ± 32.6 mmHg, p <0.001). However, the median (range) of the ED, 11.5 (4–22) and 12 (5–21) vertebrae, and SB, 3.5 (0–20) and 1 (0–20) dermatomes, values of the two groups were not related to injection speed.Conclusions and clinical relevanceThe EP profile during injection was measured by separating the injection and pressure monitoring lines. The increase in epidural injection speed increased the EP, but not the ED or the SB in dogs.
    Veterinary Anaesthesia and Analgesia 03/2014; · 1.34 Impact Factor
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    ABSTRACT: Cholecystectomy is the current standard recommended treatment for dogs with gallbladder mucoceles. However, medical management with monitoring has also been recommended for asymptomatic dogs. The purpose of this retrospective study was to compare ultrasonographic patterns of gallbladder mucoceles with clinical disease status in a group of dogs. For each included dog, the ultrasonographic pattern of the mucocele was classified into one of six types: type 1, immobile echogenic bile; type 2, incomplete stellate pattern; type 3, typical stellate pattern; type 4, kiwi like pattern and stellate combination; type 5, kiwi like pattern with residual central echogenic bile; and type 6, kiwi like pattern. A total of 43 dogs were included. Twenty-four dogs, including 11 dogs with gallbladder rupture, were symptomatic. Nineteen dogs were asymptomatic. Cholecystectomy (n = 19), medical therapy (n = 17), or monitoring (n = 6) treatments were applied according to clinical signs and owners' requests. One dog suspected of having gallbladder rupture was euthanized. Frequencies of gallbladder mucocele patterns were as follows: type 1 = 10 (23%), type 2 = 13 (30%), type 3 = 5 (12%), type 4 = 11 (26%), type 5 = 4 (9%), and type 6 = 0. In dogs with gallbladder rupture, type 2 (8/13) was the most common. No significant correlations were found between ultrasonographic patterns of gallbladder mucoceles and clinical disease status or gallbladder rupture. Findings indicated that ultrasonographic patterns of gallbladder mucoceles may not be valid bases for treatment recommendations in dogs.
    Veterinary Radiology &amp Ultrasound 11/2013; · 1.41 Impact Factor
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    ABSTRACT: The height, width, and cross sectional area of vertebral canal and spinal cord and the ratio of spinal cord to vertebral canal in the cervical spine were evaluated in cross sectional image obtained using computed tomography (CT). The measurement was made at cranial, middle, and caudal point of each cervical vertebra in clinically normal 8 small sized dogs, 10 Beagles, and 4 German Shepherds. CT myelography facilitated the delineation of the epidural space, subarachnoid space and spinal cord except at the caudal part of C7. The spinal cord showed a tendency to have clear ventral border in the middle portion of vertebral canal and lateral borders near both end plates. The height, width, and area of the vertebral canal and spinal cord in cervical vertebra were increased as the size of dog is bigger. However, the ratio of spinal cord area to vertebral canal area in small size dogs was higher than that of large size dogs. The present study could provide basic and quantitative information for CT evaluation of pathologic lesions in cervical vertebra and spinal cord.
    Journal of veterinary science (Suwŏn-si, Korea) 10/2013; · 0.89 Impact Factor
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    Jihye Choi, Hyunwook Kim, Junghee Yoon
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    ABSTRACT: This study was performed to evaluate left ventricle (LV) function using pulsed tissue Doppler imaging (TDI) in healthy dogs and to determine the normal values of TDI parameters. Longitudinal myocardial motion at the septal mitral annulus was evaluated with pulsed TDI in 45 healthy adult dogs, and maximal myocardial velocities, isovolumic time intervals, and duration of myocardial waves were determined. The correlation between time intervals and velocity variables was investigated. All velocity profiles included 1 positive systolic wave and 2 negative diastolic waves. The mean of maximal systolic velocity was 6.92 ± 1.78 cm/sec, early diastolic velocity (Em) 6.58 ± 1.81 cm/sec, late diastolic velocity (Am) 5.10 ± 2.00 cm/sec, isovolumic contraction time (IVCT) 53.61 ± 95.13 msec, and isovolumic relaxation time (IVRT) 26.74 ± 57.24 msec. Early diastolic mitral inflow velocity (E)/Em ratio and Em/Am ratio was 10.94 ± 3.27 and 1.40 ± 0.40, respectively. There were a negative correlation between the duration of Am and the amplitude of Am, and a positive correlation between IVRT and Em/Am ratio (p < 0.05). This study investigated the pulsed TDI variables including time variables such as isovolumic time interval and duration of the major wave in a large normal dog population.
    Journal of veterinary science (Suwŏn-si, Korea) 02/2013; · 0.89 Impact Factor
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    ABSTRACT: Differential diagnoses for canine liver disease are commonly based on radiographic estimates of liver size, however little has been published on breed variations. Aims of this study were to describe normal radiographic liver size in Pekingese dogs and to compare normal measurements for this breed with other dog breeds and Pekingese dogs with liver disease. Liver measurements were compared for clinically normal Pekingese (n = 61), normal non-Pekingese brachycephalic (n = 45), normal nonbrachycephalic (n = 71), and Pekingese breed dogs with liver disease (n = 22). For each dog, body weight, liver length, T11 vertebral length, thoracic depth, and thoracic width were measured on right lateral and ventrodorsal abdominal radiographs. Liver volume was calculated using a formula and ratios of liver length/T11 vertebral length and liver volume/body weight ratio were determined. Normal Pekingese dogs had a significantly smaller liver volume/body weight ratio (16.73 ± 5.67, P < 0.05) than normal non-Pekingese brachycephalic breed dogs (19.54 ± 5.03) and normal nonbrachycephalic breed dogs (18.72 ± 6.52). The liver length/T11 vertebral length ratio in normal Pekingese (4.64 ± 0.65) was significantly smaller than normal non-Pekingese brachycephalic breed dogs (5.16 ± 0.74) and normal nonbrachycephalic breed dogs (5.40 ± 0.74). Ratios of liver volume/body weight and liver length/T11 vertebral length in normal Pekingese were significantly different from Pekingese with liver diseases (P < 0.05). Findings supported our hypothesis that Pekingese dogs have a smaller normal radiographic liver size than other breeds. We recommend using 4.64× the length of the T11 vertebra as a radiographic criterion for normal liver length in Pekingese dogs.
    Veterinary Radiology &amp Ultrasound 10/2012; · 1.41 Impact Factor
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    ABSTRACT: A Yorkshire terrier (case 1) and a Miniature Schnauzer (case 2) were diagnosed with pylorogastric intussusceptions (PGIs). Both cases showed acute vomiting and had previous histories of laparotomy. In case 1, the invaginated pyloric wall was thickened unevenly containing multiple hypoechoic areas and had indistinct wall layering on ultrasonography. PGI with diffuse gastric edema and necrosis was confirmed on laparotomy. The dog recovered completely after gastrectomy and a Y-U plasty. Case 2 had uniformly thickened walls of invaginated gastric pylorus with the distinct wall layering. PGI was reduced spontaneously the next day.
    Journal of veterinary science (Suwŏn-si, Korea) 06/2012; 13(2):215-7. · 0.89 Impact Factor
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    Jihye Choi, Junghee Yoon
    Journal of Small Animal Practice 05/2012; 53(5):304. · 1.18 Impact Factor
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    ABSTRACT: Three different doses (1.0, 1.5, and 2.0 ml) of iohexol (300 mgl/ml) were injected percutaneously into the popliteal lymph node of eight adult cats under ultrasound guidance. Serial transverse CT images of five regions of interest (L3, T13, T8, T4, and T1 level) were performed at 2-min intervals, and the attenuation in Hounsfield Units (HU) of the lymphatic vessels was measured for determination of the optimal dose of iohexol and CT scan parameters. The optimal dose was 1.5 ml and helical CT acquisition is recommended to be performed as soon as possible after iohexol injection. In helical scans, the thoracic duct was characterized by variable branch numbers that formed a single trunk and entered the venous system at variable levels. CT lymphography using this protocol was performed in a cat with chylothorax. The thoracic duct was tortuous and focally dilated, and leakage of contrast medium was observed. Percutaneous CT lymphography using ultrasound-guided administration of iohexol into the popliteal lymph node appears reliable for delineation of the thoracic duct in cats.
    Veterinary Radiology &amp Ultrasound 12/2011; 53(2):174-80. · 1.41 Impact Factor
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    ABSTRACT: The objective of our study was to determine individual and global glomerular filtration rates (GFRs) using dynamic renal computed tomography (CT) in Beagle dogs. Twenty-four healthy Beagle dogs were included in the experiment. Anesthesia was induced in all dogs by using propofol and isoflurane prior to CT examination. A single slice of the kidney was sequentially scanned after a bolus intravenous injection of contrast material (iohexol, 1 mL/kg, 300 mgI/mL). Time attenuation curves were created and contrast clearance per unit volume was calculated using a Patlak plot analysis. The CT-GFR was then determined based on the conversion of contrast clearance per unit volume to contrast clearance per body weight. At the renal hilum, CT-GFR values per unit renal volume (mL/min/mL) of the right and left kidneys were 0.69 ± 0.04 and 0.57 ± 0.05, respectively. No significant differences were found between the weight-adjusted CT-GFRs in either kidney at the same renal hilum (p = 0.747). The average global GFR was 4.21 ± 0.25 mL/min/kg and the whole kidney GFR was 33.43 ± 9.20 mL/min. CT-GFR techniques could be a practical way to separately measure GFR in each kidney for clinical and research purposes.
    Journal of veterinary science (Suwŏn-si, Korea) 12/2011; 12(4):393-9. · 0.89 Impact Factor
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    ABSTRACT: To examine the spread of solution in the epidural space of sternally recumbent dogs. Prospective experimental trial. Animals  Ten healthy adult Beagle dogs weighing 7.6 ± 1.1 kg. Dogs were anaesthetized with total intravenous propofol infusion, and placed in sternal recumbency. A volume of 0.2 mL kg(-1) contrast medium (CM) containing 1% new methylene blue (MB) dye was administered into the lumbosacral epidural space. Left to right lateral radiographs using a horizontal beam were taken every 5 minutes for 45 minutes. The perpendicular height (PH) between floor of the epidural canal of the highest vertebra and that of lumbosacral spinal canal was measured on radiographs. The angle of slope from the injection point toward the highest vertebral floor was measured. Immediately after taking the last radiographic image, dogs were euthanized and a laminectomy was performed from the cervical to lumbar vertebrae for visual evaluation of MB spread. The spread of CM and of MB as counted in number of stained vertebra were compared, and each of these data sets were further compared to PH and angle, using linear regression analyses. The PH and angle were (mean ± SD) 3.8 ± 0.8 cm and 14.8 ± 2.8° respectively. The most cranial spread of CM was at 12.7 ± 5.7 (range: C6-L3) vertebrae, and at 14.0 ± 5.4 (range: C6-L2) vertebrae for MB staining. There were no significant correlations between PH and spread of CM (R(2)  = 0.08) or MB (R(2)  = 0.13), between angle and spread of CM (R(2)  = 0.05) or MB (R(2)  = 0.02), respectively. CM and MB demonstrated proportional relationship (R(2)  = 0.82, p < 0.001). No significant inhibitory effect of upward slope on cranial epidural spread of the solution was observed. Other factors may have greater effect on epidural spread in sternally recumbent dogs.
    Veterinary Anaesthesia and Analgesia 09/2011; 38(5):510-5. · 1.34 Impact Factor
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    ABSTRACT: A modified double contrast barium enema using carboxymethylcellulose was evaluated in beagle dogs and compared with dogs receiving a conventional barium enema. The experimental group was divided into three groups (1, 2, and 3) and given 30 ml/kg of different volume ratios of a barium vs. carboxymethylcellulose mixture. Each group underwent sonography following radiography. The volume ratio of one part barium to three parts carboxymethylcellulose was judged to be the optimal mixture, resulting in a general distribution of contrast and bowel radiolucency on radiographs and adequate postradiography sonography. The modified barium enema using carboxymethylcellulose is useful for assessing the general morphology and mucosal layers of the colon simultaneously on radiographs and ultrasonographs.
    Veterinary Radiology &amp Ultrasound 07/2011; 52(6):648-52. · 1.41 Impact Factor
  • Jihye Choi, Hyunwook Kim, Junghee Yoon
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    ABSTRACT: Ultrasonography is a sensitive and specific screening method for assessing the adrenal glands. The upper limit of the normal adrenal gland width is used as 7.5 mm. It is not known if adrenal gland width remains consistent with body weight. A reliable criterion of adrenal gland width in small breed dogs should be established. Small breed dogs with body weights of less than 10 kg were divided into two groups: 189 normal dogs and 22 dogs with pituitary-dependent hyperadrenocorticism (PDH). A retrospective study was conducted on dogs seen between January 1, 2006, and February 10, 2008. One hundred eighty-nine dogs of 14 different small breeds were enrolled in the normal adrenal gland group; the median gland width was 4.20 mm. Twenty-two dogs were in the PDH group; the median gland width was 6.30 mm. The cut-off value between normal adrenal glands and PDH was 6.0 mm. This figure gave a sensitivity and specificity of 75 and 94%, respectively, for detecting PDH. The adrenal gland appeared as a peanut shape with homogeneous hypoechoic parenchyma in normal dogs and in most dogs with PDH as well. This study was performed in a large population of small breed dogs and suggests that the normal adrenal gland size in small breed dogs is smaller than previously reported. We believe that a cut-off of 6.0 mm may be used as the criterion for differentiating a normal adrenal gland from adrenal hyperplasia.
    Journal of Veterinary Medical Science 04/2011; 73(8):985-9. · 0.88 Impact Factor
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    ABSTRACT: A 5-year-old male neutered Siamese cat was referred because of nasal swelling, nasal discharge, and oral respiration. Computed tomography and necropsy following euthanasia revealed a firm tan mass in the nasopharynx, occluding the nasal passage. Histologically, the nasopharyngeal mass was composed of solid nests, anastomosing cords, and closely packed glands separated by a delicate fibrovascular stroma. Individual neoplastic cells were cylindrical to polyhedral in shape, had distinct cell borders, and contained moderate amounts of finely granular eosinophilic cytoplasm and round to oval nuclei. The cytoplasmic granules were positive on phosphotungstic acid-hematoxylin staining. Immunohistochemically, the neoplastic cells were positive for cytokeratin and negative for chromogranin A, neuron-specific enolase, and vimentin. Ultrastructurally, the neoplastic cells contained numerous mitochondria.
    Journal of veterinary diagnostic investigation: official publication of the American Association of Veterinary Laboratory Diagnosticians, Inc 03/2011; 23(2):391-4. · 1.18 Impact Factor
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    ABSTRACT: To determine computed tomography (CT) delay times by use of a sequential scan and identify the normal enhancement pattern in each phase of a triphasic CT scan of the kidneys in dogs. 14 healthy Beagles. A sequential CT scan was used for investigating delay time, and a triphasic helical CT scan was used for identifying the normal enhancement pattern and determining Hounsfield unit values in the kidneys of dogs. In the cine scan (single-slice dynamic scan), the optimal delay times were 10 seconds in the corticomedullary phase and 44 seconds in the nephrographic phase, after contrast medium injection. By use of triphasic CT images, Hounsfield unit values were acquired in each phase. Triphasic CT of the kidneys in clinically normal dogs was established by acquisition of delay times in a cine scan and may become an important imaging modality in the diagnosis of renal diseases and in treatment planning in dogs.
    American Journal of Veterinary Research 03/2011; 72(3):345-9. · 1.35 Impact Factor

Publication Stats

103 Citations
55.76 Total Impact Points

Institutions

  • 2002–2014
    • Seoul National University
      • College of Veterinary Medicine
      Sŏul, Seoul, South Korea
  • 2011–2013
    • Chonnam National University
      • College of Veterinary Medicine
      Gwangju, Gwangju, South Korea
  • 2010
    • IDEXX Laboratories
      Warszawa, Masovian Voivodeship, United States