• Journal of The Korean Association For Science Education
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• v.27 no.1
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• pp.93-104
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• 2007

The purpose of this study is to investigate brain activity both during the processing of a scientific hypothesis about biological phenomena and mental arithmetic using 3.0T fMRI at the KAIST. For this study, 16 healthy male subjects participated voluntarily. Each subject's functional brain images by performing a scientific hypothesis task and a mental arithmetic task for 684 seconds were measured. After the fMRI measuring, verbal reports were collected to ensure the reliability of brain image data. This data, which were found to be adequate based on the results of analyzing verbal reports, were all included in the statistical analysis. When the data were statistically analyzed using SPM2 software, the scientific hypothesis generating process was found to have independent brain network different from the mental arithmetic process. In the scientific hypothesis process, we can infer that there is the process of encoding semantic derived from the fusiform gyrus through question-situation analysis in the pre-frontal lobe. In the mental arithmetic process, the area combining pre-frontal and parietal lobes plays an important role, and the parietal lobe is considered to be involved in skillfulness. In addition, the scientific hypothesis process was found to be accompanied by scientific emotion. These results enabled the examination of the scientific hypothesis process from the cognitive neuroscience perspective, and may be used as basic materials for developing a learning program for scientific hypothesis generation. In addition, this program can be proposed as a model of scientific brain-based learning.

• Journal of the Korean Society of Radiology
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• v.83 no.2
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• pp.432-438
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• 2022

Colonic angiosarcoma is an extremely rare and aggressive malignant tumor with poor prognosis. We report a case of colonic epithelioid angiosarcoma with colonic obstruction and rapidly progressive hepatic metastasis in a 44-year-old female. Abdominal CT revealed a heterogeneously enhancing irregular mass in the ascending colon, causing proximal bowel distension. The patient underwent surgery, and histopathological examination revealed a poorly differentiated carcinoma. A follow-up liver dynamic MRI after 4 months revealed newly developed diffusely scattered numerous small nodules in both hepatic lobes with peripheral and nodular marked arterial hyperenhancement, raising the suspicion of hepatic angiosarcoma. A pathologic second opinion was obtained, and additional immunohistochemistry revealed colonic epithelioid angiosarcoma. The patient showed progressive hepatic metastasis on follow-up abdominal CT after 6 months and died 8 months after initial diagnosis. We describe an educational case of colonic angiosarcoma, a rare malignant tumor, with rapidly progressive hepatic metastasis that showed radiologic findings suggestive of angiosarcoma and enabled a re-diagnosis for proper treatment and prognosis prediction.

• Journal of the Korean Society of Radiology
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• v.81 no.3
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• pp.719-725
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• 2020

Metastases to the thyroid gland have rarely been reported in clinical settings, and the thyroid gland is an uncommon site for breast carcinoma metastasis. We report a case of a 64-year-old breast cancer patient diagnosed with metastatic breast carcinoma in the thyroid gland after performing ultrasonography (US)-guided core needle biopsy (CNB) and subsequent total thyroidectomy. On US, the thyroid lesion appeared to be mildly enlarged with multiple internal hypoechoic lines and a few microcalcifications without mass formation. Under US-guidance, CNB was performed by targeting the area with microcalcifications and subsequently diagnosed as metastatic breast carcinoma. Total thyroidectomy revealed that the patient had metastatic invasive ductal carcinoma of the breast with lymphatic spread involving both lobes and the isthmus of the thyroid gland. Although the thyroid gland is an uncommon metastatic site, the unusual features of thyroid metastasis can be observed on US; thus, US-guided CNB effectively aids the diagnosis of thyroid metastasis.

• Korean Journal of Radiology
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• v.2 no.3
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• pp.138-144
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• 2001

Objective: Bronchogenic carcinoma can mimic or be masked by pulmonary tuberculosis (TB), and the aim of this study was to describe the radiologic findings and clinical significance of bronchogenic carcinoma and pulmonary TB which coexist in the same lobe. Materials and Methods: The findings of 51 patients (48 males and three females, aged 48-79 years) in whom pulmonary TB and bronchogenic carcinoma coexisted in the same lobe were analyzed. The morphologic characteristics of a tumor, such as its diameter and margin, the presence of calcification or cavitation, and mediastinal lymphadenopathy, as seen at CT, were retrospectively assessed, and the clinical stage of the lung cancer was also determined. Using the serial chest radiographs available for 21 patients, the possible causes of delay in the diagnosis of lung cancer were analyzed. Results: Lung cancers with coexisting pulmonary TB were located predominantly in the upper lobes (82.4%). The mean diameter of the mass was 5.3 cm, and most tumors (n=42, 82.4%) had a lobulated border. Calcification within the tumor was seen in 20 patients (39.2%), and cavitation in five (9.8%). Forty-two (82.4%) had mediastinal lymphadenopathy, and more than half the tumors (60.8%) were at an advanced stage [IIIB (n=11) or IV (n=20)]. The average delay in diagnosing lung cancer was 11.7 (range, 1-24) months, and the causes of this were failure to observe new nodules masked by coexisting stable TB lesions (n=8), misinterpretation of new lesions as aggravation of TB (n=5), misinterpretation of lung cancer as tuberculoma at initial radiography (n=4), masking of the nodule by an active TB lesion (n=3), and subtleness of the lesion (n=1). Conclusion: Most cancers concurrent with TB are large, lobulated masses with mediastinal lymphadenopathy, indicating that the morphologic characteristics of lung cancer with coexisting pulmonary TB are similar to those of lung cancer without TB. The diagnosis of lung cancer is delayed mainly because of masking by a tuberculous lesion, and this suggests that in patients in whom a predominant or growing nodule is present and who show little improvement of symptoms despite antituberculous or other medical therapy, coexisting cancer should be suspected.

• Korean Journal of Radiology
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• v.21 no.6
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• pp.736-745
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• 2020

Objective: To identify the initial chest computed tomography (CT) findings and clinical characteristics associated with the course of coronavirus disease 2019 (COVID-19) pneumonia. Materials and Methods: Baseline CT scans and clinical and laboratory data of 72 patients admitted with COVID-19 pneumonia (39 men, 46.2 ± 15.9 years) were retrospectively analyzed. Baseline CT findings including lobar distribution, presence of ground glass opacities, consolidation, linear opacities, and lung severity score were evaluated. The outcome event was recovery with hospital discharge. The time from symptom onset to discharge or the end of follow-up (for those remained hospitalized) was recorded. Data were censored in events such as death or discharge without recovery. Multivariable Cox proportional hazard regression was used to explore the association between initial CT, clinical or laboratory findings, and discharge with recovery, whereby hazard ratio (HR) values < 1 indicated a lower rate of discharge at four weeks and longer time until discharge. Results: Thirty-two patients recovered and were discharged during the study period with a median length of admission of 16 days (range, 9 to 25 days), while the rest remained hospitalized at the end of this study (median, 17.5 days; range, 4 to 27 days). None died during the study period. After controlling for age, onset time, lesion characteristics, number of lung lobes affected, and bilateral involvement, the lung severity score on baseline CT (> 4 vs. ≤ 4 [reference]: adjusted HR = 0.41 [95% confidence interval, CI = 0.18-0.92], p = 0.031) and initial lymphocyte count (reduced vs. normal or elevated [reference]: adjusted HR = 0.14 [95% CI = 0.03-0.60], p = 0.008) were two significant independent factors that influenced recovery and discharge. Conclusion: Lung severity score > 4 and reduced lymphocyte count at initial evaluation were independently associated with a significantly lower rate of recovery and discharge and extended hospitalization in patients admitted for COVID-19 pneumonia.

• The Journal of the Acoustical Society of Korea
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• v.43 no.3
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• pp.361-367
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• 2024

Ultrasound in the air is widely used in industry as a measurement technique to prevent abnormalities in the machinery. Recently, the use of airborne ultrasound imaging techniques, which can find the location of abnormalities using an array transducers, is increasing. A beamforming method that uses the phase difference for each sensor is used to visualize the location of the ultrasonic sound source. We exploit a random sparse ultrasonic array and obtain beamforming power distribution on the source in a certain distance away from the array. Conventional beamforming methods inevitably have limited spatial resolution depending on the number of sensors used and the aperture size. A high-resolution ultrasound imaging technique was implemented by applying functional beamforming as a method to overcome the geometric constraints of the array. The functional beamforming method can be expressed as a generalized beam forming method mathematically, and has the advantage of being able to obtain high-resolution imaging by reducing main-lobe width and side lobes. As a result of observation through computer simulation, it was verified that the resolution of the ultrasonic source in the air was successfully increased by functional beamforming using the ultrasonic sparse array.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.1
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• pp.17-28
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• 2008

Purpose: It was well known that cerebral blood perfusion is normal or diffusely decreased in the majority of patients with Parkinson's disease (PD). Actually we interpreted brain perfusion SPECT images of PD patients in the clinical situation, we observed various cerebral perfusion patterns in patients with PD. So we performed brain perfusion SPECT to know the brain perfusion patterns of PD patients and the difference of perfusion patterns according to the sex and the age. Also we classified PD patients into small groups based on the brain perfusion pattern. Methods and Materials: Two hundred nineteen patients (M: 70, F: 149, mean age: $62.9{\pm}6.9$ y/o) who were diagnosed as PD without dementia clinically and 55 patients (M:15, F:40, mean age: $61.4{\pm}9.2$ y/o) as normal controls who had no past illness history were performed $^{99m}Tc$-HMP AO brain perfusion SPECT and neuropsychological test. Results: At first, we compared all patients with PD and normal controls. Brain perfusion in left inferior frontal gyrus, left insula, left transverse temporal gyrus, left inferior parietal lobule, left superior parietal lobule, right precuneus, right caudate tail were lower in patients with PD than normal controls. Secondly, we compared male and female patients with PD and normal controls, respectively. Brain perfusion SPECT showed more decreased cerebral perfusion in left hemisphere than right side in both male and female patients compared to normal controls. And there was larger hypoperfusion area in female patients compared with male. Thirdly, we classified patients with PD and normal controls into 4 groups according to the age and compared brain perfusion respectively. In patient below fifties, brain perfusion in both occipitoparietal and left temporal lobe were lower in PD group. As the patients with PD grew older, hypoperfusion area were shown in both frontal, temporal and limbic lobes. Fourthly, We were able to divide patients into small groups based on cerebral perfusion pattern. There was normal cerebral blood perfusion in 32 (14.7%) of 219 patients with PD, decreased perfusion on the frontal lobe in 45 patients (20.6%), the temporal lobe in 39 patients (17.4%), the parietal lobe in 39 patients (17.9%), the occipital lobe in 40 patients (18.3%), diffuse area in 14 patients (6.4%) and unclassified in 10 patients (4.6%). Fifthly, we compared the results of the neuropsychological test and cerebral perfusion pattern. There was no correlation between two tests except visuospatial function. Conclusion: Various perfusion state were found in patients with PD according to the age and sex. Also we were able to classify perfusion state into several groups and compare the neuropsychological test with cerebral perfusion.

• Radiation Oncology Journal
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• v.9 no.1
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• pp.47-52
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• 1991

From April,1983 through April,1989, we have treated histologically proven 21 patients with oligodendroglioma using 6 MV linear accelerator at the Division of Radiation Therapy, Kangnam 51. Mary's Hospital Catholic University Medical College. These are 8% of the irradiated 246 primary brain tumors during the same period. To investigate influencing factors on the survival of irradiated U patients with oligodendroglioma, we analyzed the cerebral location of the involvements, initial symptoms, CT findings and survival rates, retrospectively. One case was lost to follow up and excluded from survival data. Of the 28 patients, thirteen were male and 8 female. Ages ranged from 5 to 68 years with a median age of 38 years. Radiation doses varied from 3900 cGy to 0480 cGy and were given for 5 to 8 weeks. All but one were supratentorial. The involvement of the frontal and parietal lobes were 10 (48%) patients in each and temporal lobe in 8 (38.1%). Histological diagnosis was made by stereotactic biopsy in 3 and postoperatively in 18. The type of surgery was divided into partial, subtotal and total resection in 7,9 and 2 cases respectively. In 6 cases, chemotherapy was also tried during or after radiation therapy. Major presenting symptoms were headache, cerebral motor, nausea & vomiting and epilepsy in 18,12, 7 and 5 respectively in decreasing order. In CT analysis, low density (02%), cystic mass (33%), calcifiestion (66%) and positive contrast enhancement (42.8%) were observed as the highest frequency. Mean survival duration after radiation therapy was 38 months (K-M methods). We could not achieve statistically significant factors influencing on the survival rate after radiation therapy for oligodendrogliomas by one or two tail test.

• Nuclear Medicine and Molecular Imaging
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• v.40 no.1
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• pp.40-47
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• 2006

Purpose: The aim of this study was to examine the effects of attenuation correction (AC) and scatter correction (SC) on the quantification of PET count rates. Materials and Methods: To assess the effects of AC and SC $^{18}F$-FDG PET images of phantom and cat brain were acquired using microPET R4 scanner. Thirty-minute transmission images using $^{68}Ge$ source and emission images after injection of FDG were acquired. PET images were reconstructed using 2D OSEM. AC and SC were applied. Regional count rates were measured using ROIs drawn on cerebral cortex including frontal, parietal, and latral temporal lobes and deep gray matter including head of caudate nucleus, putamen and thalamus for pre- and post-AC and SC images. The count rates were then normalized with the injected dose per body weight. To assess the effects of AC, count ratio of "deep gray matter/cerebral cortex" was calculated. To assess the effects of SC, ROIs were also drawn on the gray matter (GM) and white matter (WM), and contrast between them ((GM-WM)/GM was measured. Results: After the AC, count ratio of "deep gray matter/cerebral cortex" was increased by $17{\pm}7%$. After the SC, contrast was also increased by $12{\pm}3%$. Conclusion: Relative count of deep gray matter and contrast between gray and white matters were increased after AC and SC, suggesting that the AC would be critical for the quantitative analysis of cat brain PET data.

• Journal of Veterinary Clinics
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• v.32 no.5
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• pp.469-472
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• 2015

A 10-year-old, castrated poodle dog presented with a cough for 2 weeks, and the cough initially developed since very young age. On radiographs, pneumothorax was noticed by characteristics of radiolucent area without pulmonary markings along the thoracic wall and diaphragm, retracted lung lobes from the thoracic wall and severely decreased volume of the left cranial lung lobe with disconnected bronchus. Computed tomography (CT) findings identified several pulmonary air-filled cysts and collapsed lung with abnormal shape and non-tapered end of bronchus, bronchioles at the accessory lobe and left cranial lobe. Also, pneumothorax, pneumomediastinum and subcutaneous emphysema were found. Imaging diagnosis was the spontaneous pneumothorax caused by ruptured emphysematous bullae associated with congenital bronchial cartilage abnormality or bronchial tree malformation. On surgery, hypoplasia of the left cranial lobe, right middle lobe, and accessory lobe with a bulla where air was leaking was identified. The accessory lobe was partially resected and bronchial cartilage hypoplasia was confirmed by histopathologic examination.