• Journal of Veterinary Clinics
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• v.33 no.1
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• pp.51-57
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• 2016

In this study, the features of canine lymphoma on fluorine-18 fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) were evaluated in three small breed dogs. In case 1, ultrasonography and CT indicated neoplastic involvement of the sternal, right axillary, submandibular, lower cervical, tracheobronchial, mesenteric, and sublumbar lymph nodes; spleen; and liver. However, intense FDG uptake on PET/CT images was detected only for the lymph nodes and spleen. No FDG uptake by the liver was detected for case 1 despite the confirmation of lymphoma by cytology. In case 2, ultrasonography and CT indicated neoplastic involvement of the axillary, mesenteric, and sublumbar lymph nodes and the spleen, while intense FDG uptake on PET/CT images was detected for the axillary and a few mesenteric lymph nodes, and the spleen. FDG uptake was additionally observed from popliteal lymph nodes, however there was no uptake by the sublumbar lymph nodes and some mesenteric lymph nodes. In case 3, neoplastic changes in the splenic, mesenteric, and sublumbar lymph nodes and spleen were suspected on ultrasonography, and lower cervical and popliteal lymph node involvements were additionally detected on PET/CT. Compared to ultrasonography, repeated PET/CT showed increased FDG uptake by the lymph nodes at an earlier stage after chemotherapy in case 3. This study illustrated the features of PET/CT in canine lymphomas and compared those to ultrasonography and CT findings. FDG uptakes were not detected from some lesions which were suspected to be neoplastic involvement in case 1 and 2. We could not clearly explain the reason of this result in the present study because cytological or histological examination was not performed for lesions that showed different results on ultrasonography, CT, and PET/CT. Further studies on the subclassification of canine lymphoma and the sensitivity and specificity of PET/CT for the detection of canine lymphoma are required. PET/CT data can provide useful information for predicting the therapeutic response at an early stage after treatment.

• Journal of the Korea Society of Computer and Information
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• v.24 no.3
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• pp.41-47
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• 2019

In this paper, we propose a application of conditional generative adversarial network (cGAN) for generation of contrast enhanced computed tomography (CT) image. Two types of CT data which were the enhanced and non-enhanced were used and applied by the histogram equalization for adjusting image intensities. In order to validate the generation of contrast enhanced CT data, the structural similarity index measurement (SSIM) was performed. Prepared generated contrast CT data were analyzed the statistical analysis using paired sample t-test. In order to apply the optimized algorithm for the lymph node cancer, they were calculated by short to long axis ratio (S/L) method. In the case of the model trained with CT data and their histogram equalized SSIM were $0.905{\pm}0.048$ and $0.908{\pm}0.047$. The tumor S/L of generated contrast enhanced CT data were validated similar to the ground truth when they were compared to scanned contrast enhanced CT data. It is expected that advantages of Generated contrast enhanced CT data based on deep learning are a cost-effective and less radiation exposure as well as further anatomical information with non-enhanced CT data.

• Journal of Trauma and Injury
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• v.23 no.1
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• pp.38-42
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• 2010

Purpose: The clinical utility of brain computed tomography (CT) in detecting temporal bone fracture is not well established. We performed this study to determine the utility of brain computed tomography (CT) in detecting fractures of the temporal bones in correlation with fracture patterns. We used high resolution computed tomography (HRCT) as the gold standard for diagnosing temporal bone fracture and its pattern. Methods: From January 2007 to December 2009, patients who underwent both brain CT and HRCT within 10 days of head trauma were investigated. Among them, 58 cases of temporal bone fracture confirmed by HRCT were finally included. Fracture patterns (transverse or non-transverse, otic capsule sparing or otic capsule violating) were determined by HRCT. Brain CT findings in correlation with fracture patterns were analyzed. Results: Among 58 confirmed cases of temporal bone fracture by HRCT, 14 cases (24.1%) were not detected by brain CT. Brain CT showed a significantly lower ability to detect temporal bone fracture with transverse component than without transverse component (p=0.020). Moreover, brain CT showed lower ability to detect otic capsule violating pattern than otic capsule sparing pattern (p=0.015). Among the 14 cases of temporal bone fracture that were not detected by brain CT, 4 cases lacked any objective physical findings (facial palsy, hemotympanum, external auditory canal bleeding) suggesting fractures of the temporal bones. Conclusion: Brain CT showed poor ability to detect temporal bone fracture with transverse component and otic capsule violating pattern, which is associated with a poorer clinical outcome than otic capsule sparing pattern. Routine use of HRCT to identify temporal bone fracture is warranted, even in cases without evidence of temporal bone fracture on brain CT scans or any objective physical findings suggestive of temporal bone fracture.

• Korean Journal of Radiology
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• v.21 no.8
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• pp.1018-1023
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• 2020

The coronavirus disease (COVID-19) outbreak has reached global pandemic status as announced by the World Health Organization, which currently recommends reverse transcription polymerase chain reaction (RT-PCR) as the standard diagnostic tool. However, although the RT-PCR test results may be found negative, there are cases that are found positive for COVID-19 pneumonia on computed tomography (CT) scan. CT is also useful in assessing the severity of COVID-19 pneumonia. When clinicians desire a CT scan of a patient with COVID-19 to monitor treatment response, a safe method for patient transport is necessary. To address the engagement of medical resources necessary to transport a patient with COVID-19, our institution has implemented the use of mobile CT. Therefore, we report two cases of COVID-19 pneumonia evaluated by using mobile cone-beam CT. Although mobile cone-beam CT had some limitations regarding its image quality such as scatter noise, motion and streak artifacts, and limited field of view compared with conventional multi-detector CT, both cases had acceptable image quality to establish the diagnosis of COVID-19 pneumonia. We report the usefulness of mobile cone-beam CT in patients with COVID-19 pneumonia.

• Journal of Veterinary Clinics
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• v.27 no.6
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• pp.686-692
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• 2010

Computed tomography (CT) is considered as gold standard in evaluating pancreatitis in human, but there have been only a few studies in veterinary field. Balthazar CT severity index (CTSI) used to assess the severity of acute necrotizing pancreatitis in human could be applicable to dogs, because the severity of acute pancreatitis depends on the area of pancreatic necrosis in dogs more than in human. In this study, 25 adult, clinically healthy beagle dogs were used. CT examinations was performed in normal pancreas, positive control group and acute necrotizing pancreatitis induced by autologous bile injection. Balthazar CTSI was applied to canine acute necrotizing pancreatitis in contrastenhanced CT image and compared with the result of histopathologic examination. The Hounsfield unit (HU) of normal canine pancreas was $52.44{\pm}4.58$ and the density was significantly decreased in acute necrotizing pancreatitis (P < .05). In contrast-enhanced CT examination, pancreatic density was decreased significantly and this area was compatible to pancreatic necrosis. Balthazar CTSI showed positive correlation with histopathologic evaluation with a sensitivity of 100% and a specificity of 88.89%. Balthazar CTSI can be applied to evaluate the severity of acute necrotizing pancreatitis in dogs.

• Journal of Gastric Cancer
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• v.14 no.1
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• pp.1-6
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• 2014

Aerobic glycolysis has been the most important hypothesis in cancer metabolism. It seems to be related to increased bioenergetic and biosynthetic needs in rapidly proliferating cancer cells. To this end, F-18 fluorodeoxyglucose (FDG), a glucose analog, became widely popular for the detection of malignancies combined with positron emission tomography/computed tomography (PET/CT). Although the potential roles of FDG PET/CT in primary tumor detection are not fully established, it seems to have a limited sensitivity in detecting early gastric cancer and mainly signet ring or non-solid types of advanced gastric cancer. In evaluating lymph node metastases, the location of lymph nodes and the degree of FDG uptake in primary tumors appear to be important factors affecting the diagnostic accuracy of PET/CT. In spite of the limited sensitivity, the high specificity of PET/CT for lymph node metastases may play an important role in changing the extent of lymphadenectomy or reducing futile laparotomies. For peritoneal metastases, PET/CT seems to have a poorer sensitivity but a better specificity than CT. The roles of PET/CT in the evaluation of other distant metastases are yet to be known. Studies including primary tumors with low FDG uptake or peritoneal recurrence seem suffer from poorer diagnostic performance for the detection of recurrent gastric cancer. There are only a few reports using FDG PET/CT to predict response to neoadjuvant or adjuvant chemotherapy. A complete metabolic response seems to be predictive of more favorable prognosis.

• Imaging Science in Dentistry
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• v.34 no.3
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• pp.159-164
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• 2004

Purpose: To compare alveolar bony height of pantomograph with bony height of thin slice, multiplanar reformatted (MPR) Computed Tomograph. Materials and Methods : Panoramic radiograms of 12 young adult patients had been taken by one radologic technitian and the measurements were corrected by magnification ratio (1.20). The slice thickness of Multi-detector Computed Tomography (CT) was at least 1mm for the accuracy. The raw CT datas were imported into the V-works 4.0 (CyberMed Corp., Seoul, Korea) and transformed to MPR images. Pantomographic measurements of alveolar bone were compared to CT values by average mean bony height measurements for the accuracy. Inter-, and Intra-observer variability was evaluated. Results : There was no significant differences between height measurement of pantomography and that of CT (P>0.05). There were no significant differences in either inter-or intra-observer measurements (P>0.05). Conclusion : Pantomography showed relatively high accuracy and precision in measuring alveolar bony height.

• Archives of Craniofacial Surgery
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• v.18 no.1
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• pp.21-24
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• 2017

Background: In evaluation of craniosynostosis patients in terms of neurodevelopmental delay, positron emission tomography computed tomography (PET-CT) scan can be used to assess brain abnormalities through glucose metabolism. We aimed to determine the unnecessity of PET-CT in this study. Methods: Thirty-eight patients diagnosed with craniosynostosis who underwent distraction osteogenesis from October, 2010 to November, 2013 were reviewed. Magnetic resonance imaging (MRI) and PET-CT scan were carried out for evaluation of the brain structure and function, whereas X-ray and CT scan were taken for evaluation of the skull. Results: Nine patients reported abnormal MRI findings which were not significant, and five patients showed local problem on brain on PET-CT scan. No correlation was found among them. Conclusion: PET-CT evaluation of possible abnormal brain findings do not affect surgical planning or require additional therapy. Preoperative PET-CT scan is not the essential study to get any etiologic information of the disease consequences or to establish the treatment plan.

• Imaging Science in Dentistry
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• v.44 no.4
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• pp.279-285
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• 2014

Purpose: To assess the influence of anatomic location on the relationship between computed tomography (CT) number and X-ray attenuation in limited and medium field-of-view (FOV) scans. Materials and Methods: Tubes containing solutions with different concentrations of $K_2HPO_4$ were placed in the tooth sockets of a human head phantom. Cone-beam computed tomography (CBCT) scans were acquired, and CT numbers of the $K_2HPO_4$ solutions were measured. The relationship between CT number and $K_2HPO_4$ concentration was examined by linear regression analyses. Then, the variation in CT number according to anatomic location was examined. Results: The relationship between $K_2HPO_4$ concentration and CT number was strongly linear. The slopes of the linear regressions for the limited FOVs were almost 2-fold lower than those for the medium FOVs. The absolute CT number differed between imaging protocols and anatomic locations. Conclusion: There is a strong linear relationship between X-ray attenuation and CT number. The specific imaging protocol and anatomic location of the object strongly influence this relationship.

• Korean Journal of Radiology
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• v.22 no.4
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• pp.604-611
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• 2021

Objective: The aim of this pilot study was to investigate the potential of early-phase single-photon emission computed tomography (SPECT)/computed tomography (CT) using technetium-99m methyl diphosphonate (^99mTc-MDP) for diagnosing osteomyelitis (OM). Materials and Methods: Twenty-one patients with suspected OM were enrolled retrospectively. Three-phase bone scan (TPBS), early-phase SPECT/CT (immediately after blood pool planar imaging), and delayed-phase SPECT/CT (immediately after delayed planar imaging) were performed. The final diagnoses were established through surgery or clinical follow-up for over 6 months. We compared three diagnostic criteria based on (I) TPBS alone, (II) combined TPBS and delayed-phase SPECT/CT, and (III) early-phase SPECT/CT alone. Results: OM was diagnosed in 11 of 21 patients (nine surgically and two clinically). Of the 11 OM patients, criterion-I, criterion-II, and criterion-III were positive in six, seven, and 10 patients, respectively. Of the 10 non-OM patients, criterion-I, criterion-II, and criterion-III were negative in five, five, and seven patients, respectively. The sensitivity/specificity/accuracy of criterion-I, criterion-II, and criterion-III for diagnosing OM were 54.5%/50.0%/55.0%, 63.6%/50.0%/57.1%, and 90.9%/70.0%/87.5%, respectively. Conclusion: This pilot study demonstrated the potential of using the early-phase SPECT/CT to diagnose OM. Based on the results, prospective studies with a larger sample size should be conducted to confirm the efficacy of early-phase SPECT/CT.