• Korean Journal of Radiology
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• v.24 no.11
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• pp.1081-1092
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• 2023

Objective: To investigate the incidence of microvascular myocardial ischemia in diabetic patients without obstructive coronary artery disease (CAD) and its relationship with angina. Materials and Methods: Diabetic patients and an intermediate-to-high pretest probability of CAD were prospectively enrolled. Non-diabetic patients but with an intermediate-to-high pretest probability of CAD were retrospectively included as controls. The patients underwent dynamic computed tomography-myocardial perfusion imaging (CT-MPI) and coronary computed tomography angiography (CCTA) to quantify coronary stenosis, myocardial blood flow (MBF), and extracellular volume (ECV). The proportion of patients with microvascular myocardial ischemia, defined as any myocardial segment with a mean MBF ≤ of 100 mL/min/100 mL, in patients without obstructive CAD (Coronary Artery Disease-Reporting and Data System [CAD-RADS] grade 0-2 on CCTA) was determined. Various quantitative parameters of the patients with and without diabetes without obstructive CAD were compared. Multivariable analysis was used to determine the association between microvascular myocardial ischemia and angina symptoms in diabetic patients without obstructive CAD. Results: One hundred and fifty-two diabetic patients (mean age: 59.7 ± 10.7; 77 males) and 266 non-diabetic patients (62.0 ± 12.3; 167 males) were enrolled; CCTA revealed 113 and 155 patients without obstructive CAD, respectively. For patients without obstructive CAD, the mean global MBF was significantly lower for those with diabetes than for those without (152.8 mL/min/100 mL vs. 170.4 mL/min/100 mL, P < 0.001). The mean ECV was significantly higher for diabetic patients (27.2% vs. 25.8%, P = 0.009). Among the patients without obstructive CAD, the incidence of microvascular myocardial ischemia (36.3% [41/113] vs. 10.3% [16/155], P < 0.001) and interstitial fibrosis (69.9% [79/113] vs. 33.3% [8/24], P = 0.001) were significantly higher in diabetic patients than in the controls. The presence of microvascular myocardial ischemia was independently associated with angina symptoms (adjusted odds ratio = 3.439, P = 0.037) in diabetic patients but without obstructive CAD. Conclusion: Dynamic CT-MPI + CCTA revealed a high incidence of microvascular myocardial ischemia in diabetic patients without obstructive CAD. Microvascular myocardial ischemia is strongly associated with angina.

• Korean Journal of Radiology
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• v.20 no.4
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• pp.671-682
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• 2019

Objective: To investigate whether computed tomography (CT) and fluorine-18-labeled fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET) may be applied to distinguish thymic epithelial tumors (TETs) from benign cysts in the anterior mediastinum. Materials and Methods: We included 262 consecutive patients with pathologically proven TETs and benign cysts 5 cm or smaller who underwent preoperative CT scans. In addition to conventional morphological and ancillary CT findings, the relationship between the lesion and the adjacent mediastinal pleura was evaluated qualitatively and quantitatively. Mean lesion attenuation was measured on CT images. The maximum standardized uptake value (SUVmax) was obtained with FDG-PET scans in 40 patients. CT predictors for TETs were identified with multivariate logistic regression analysis. For validation, we assessed the diagnostic accuracy and inter-observer agreement between four radiologists in a size-matched set of 24 cysts and 24 TETs using a receiver operating characteristic curve before and after being informed of the study findings. Results: The multivariate analysis showed that post-contrast attenuation of 60 Hounsfield unit or higher (odds ratio [OR], 12.734; 95% confidence interval [CI], 2.506-64.705; p = 0.002) and the presence of protrusion from the mediastinal pleura (OR, 9.855; 95% CI, 1.749-55.535; p = 0.009) were the strongest CT predictors for TETs. SUVmax was significantly higher in TETs than in cysts (5.3 ± 2.4 vs. 1.1 ± 0.3; p < 0.001). After being informed of the study findings, the readers' area under the curve improved from 0.872-0.955 to 0.949-0.999 (p = 0.066-0.149). Inter-observer kappa values for protrusion were 0.630-0.941. Conclusion: Post-contrast CT attenuation, protrusion from the mediastinal pleura, and SUVmax were useful imaging features for distinguishing TETs from cysts in the anterior mediastinum.

• Korean Journal of Radiology
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• v.21 no.9
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• pp.1036-1044
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• 2020

Objective: To investigate the clinical feasibility of synthetic diffusion-weighted imaging (sDWI) at different b-values in patients with breast cancer by assessing the diagnostic image quality and the quantitative measurements compared with conventional diffusion-weighted imaging (cDWI). Materials and Methods: Fifty patients with breast cancer were assessed using cDWI at b-values of 800 and 1500 s/mm² (cDWI₈₀₀ and cDWI₁₅₀₀) and sDWI at b-values of 1000 and 1500 s/mm² (sDWI₁₀₀₀ and sDWI₁₅₀₀). Qualitative analysis (normal glandular tissue suppression, overall image quality, and lesion conspicuity) was performed using a 4-point Likert-scale for all DWI sets and the cancer detection rate (CDR) was calculated. We also evaluated cancer-to-parenchyma contrast ratios for each DWI set in 45 patients with the lesion identified on any of the DWI sets. Statistical comparisons were performed using Friedman test, one-way analysis of variance, and Cochran's Q test. Results: All parameters of qualitative analysis, cancer-to-parenchyma contrast ratios, and CDR increased with increasing b-values, regardless of the type of imaging (synthetic or conventional) (p < 0.001). Additionally, sDWI₁₅₀₀ provided better lesion conspicuity than cDWI₁₅₀₀ (3.52 ± 0.92 vs. 3.39 ± 0.90, p < 0.05). Although cDWI₁₅₀₀ showed better normal glandular tissue suppression and overall image quality than sDWI₁₅₀₀ (3.66 ± 0.78 and 3.73 ± 0.62 vs. 3.32 ± 0.90 and 3.35 ± 0.81, respectively; p < 0.05), there was no significant difference in their CDR (90.0%). Cancer-to-parenchyma contrast ratios were greater in sDWI₁₅₀₀ than in cDWI₁₅₀₀ (0.63 ± 0.17 vs. 0.55 ± 0.18, p < 0.001). Conclusion: sDWI₁₅₀₀ can be feasible for evaluating breast cancers in clinical practice. It provides higher tumor conspicuity, better cancer-to-parenchyma contrast ratio, and comparable CDR when compared with cDWI₁₅₀₀.

• 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.

• Journal of Korean Physical Therapy Science
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• v.31 no.3
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• pp.31-50
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• 2024

Background: The lung capacity prediction formula in Korea is an important judgment standard. Since there is no appropriate lung capacity prediction formula, various prediction formulas are used for foreigners such as Northeast Asians. The purpose of this study is to develop a lung capacity prediction equation by selecting data and setting the selection criteria for normal subjects in accordance with international standards through strict quality control, and to propose a new prediction model. Design: Preliminary feasibility study Methods: A total of 857 people who met the criteria for normal people were finally collected. The tester used for the lung capacity test was the V-Max Encore 22 (Carefusion, California, USA), which is a lung capacity tester proposed by the Korean Society of Tuberculosis and Respiratory Medicine and satisfies accuracy and precision. Among the indicators measured using spirometry, forced vital capacity (FVC), forced expiratory volume in 1 second (FEV₁), forced expiratory volume ratio in 1 second (FEV₁/FVC), forced mid-expiratory flow (Forced expiratory flow 25-75%, FEF25-75%) and peak expiratory flow (PEF) values were collected. Results: This study confirmed a significant correlation between age, height, weight, and pulmonary function indicators. Additionally, it found a correlation between body mass index, which considers the diversity of physical conditions, and pulmonary function indicators. Graphs depicting age-specific pulmonary function indicators by gender, presented as generalized additive model results from collected data, showed a pattern where both FVC and FEV1 increased until the mid-20s and then gradually decreased with aging. FEV1% and PEF exhibited a continuous decrease with aging. Conclusion: This study confirms that there is a significant correlation between weight and pulmonary function in the prediction formula for lung capacity. Additionally, it verifies the correlation between body mass index, which considers the diversity of physical conditions, and pulmonary function. The study suggests that the predicted values are relatively low due to factors such as aging and environmental influences like COVID-19. This preliminary study holds clinical significance for improving the diagnostic accuracy of respiratory symptoms in the elderly.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.1
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• pp.29-38
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• 2008

Purpose: The aim of this study was to investigate the feasibility of 3 ' -[F-18]fluoro-3 ' -deoxythymidine positron emission tomography(FLT-PET) for the detection of locally advanced breast cancer and to compare the degree of FLT and 2' -deoxy-2 ' -[F-18]fluoro-d-glucose(FDG) uptake in primary tumor, lymph nodes and other normal organs. Material & Methods: The study subjects consisted of 22 female patients (mean age; $42{\pm}6$ years) with biopsy-confirmed infiltrating ductal carcinoma between Aug 2005 and Nov 2006. We performed conventional imaging workup, FDG-PET and FLT PET/CT. Average tumor size measured by MRI was $7.2{\pm}3.4$ cm. With visual analysis, Tumor and Lymph node uptakes of FLT and FDG were determined by calculation of standardized uptake value (SUV) and tumor to background (TB) ratio. We compared FLT tumor uptake with FDG tumor uptake. We also investigated the correlation between FLT tumor uptake and FDG tumor uptake and the concordant rate with lymph node uptakes of FLT and FDG. FLT and FDG uptakes of bone marrow and liver were measured to compare the biodistribution of each other. Results: All tumor lesions were visually detected in both FLT-PET and FDG-PET. There was no significant correlation between maximal tumor size by MRI and SUVmax of FLT-PET or FDG-PET (p>0.05). SUVmax and $$SUV_{75} (average SUV within volume of interest using 75% isocontour) of FLT-PET were significantly lower than those of FDG-PET in primary tumor (SUVmax; $6.3{\pm}5.2\;vs\;8.3{\pm}4.9$, p=0.02 /$SUV_{75};\;5.3{\pm}4.3\;vs\;6.9{\pm}4.2$, p=0.02). There is significant moderate correlation between uptake of FLT and FDG in primary tumor (SUVmax; rho=0.450, p=0.04 / SUV75; rho=0.472, p=0.03). But, TB ratio of FLT-PET was higher than that of FDG-PET($11.7{\pm}7.7\;vs\;6.3{\pm}3.8$, p=0.001). The concordant rate between FLT and FDG uptake of lymph node was reasonably good (33/34). The FLT SUVs of liver and bone marrow were $4.2{\pm}1.2\;and\;8.3{\pm}4.9$. The FDG SUVs of liver and bone marrow were $1.8{\pm}0.4\;and\;1.6{\pm}0.4$. Conclusion: The uptakes of FLT were lower than those of FDG, but all patients of this study revealed good FLT uptakes of tumor and lymph node. Because FLT-PET revealed high TB ratio and concordant rate with lymph node uptakes of FDG-PET, FLT-PET could be a useful diagnostic tool in locally advanced breast cancer. But, physiological uptake and individual variation of FLT in bone marrow and liver will limit the diagnosis of bone and liver metastases.

• Investigative Magnetic Resonance Imaging
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• v.15 no.1
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• pp.22-31
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• 2011

Purpose : To compare free-breathing and respiratory-triggered diffusion-weighted imaging on 1.5-T MR system in the detection of hepatic lesions. Materials and Methods: This single-institution study was approved by our institutional review board. Forty-seven patients (mean 57.9 year; M:F = 25:22) underwent hepatic MR imaging on 1.5-T MR system using both free-breathing and respiratory-triggered diffusion-weighted imaging (DWI) at a single examination. Two radiologists retrospectively reviewed respiratory-triggered and free-breathing sets (B50, B400, B800 diffusion weighted images and ADC map) in random order with a time interval of 2 weeks. Liver SNR and lesion-to-liver CNR of DWI were calculated measuring ROI. Results : Total of 62 lesions (53 benign, 9 malignant) that included 32 cysts, 13 hemangiomas, 7 hepatocellular carcinomas (HCCs), 5 eosinophilic infiltration, 2 metastases, 1 eosinophilic abscess, focal nodular hyperplasia, and pseudolipoma of Glisson's capsule were reviewed by two reviewers. Though not reaching statistical significance, the overall lesion sensitivities were increased in respiratory-triggered DWI [reviewer1: reviewer2, 47/62(75.81%):45/62(72.58%)] than free-breathing DWI [44/62(70.97%):41/62(66.13%)]. Especially for smaller than 1 cm hepatic lesions, sensitivity of respiratory-triggered DWI [24/30(80%):21/30(70%)] was superior to free-breathing DWI [17/30(56.7%):15/30(50%)]. The diagnostic accuracy measuring the area under the ROC curve (Az value) of free-breathing and respiratory-triggered DWI was not statistically different. Liver SNR and lesion-to-liver CNR of respiratory-triggered DWI ($87.6{\pm}41.4$, $41.2{\pm}62.5$) were higher than free-breathing DWI ($38.8:{\pm}13.6$, $24.8{\pm}36.8$) (p value < 0.001, respectively). Conclusion: Respiratory-triggered diffusion-weighted MR imaging seemed to be better than free-breathing diffusion-weighted MR imaging on 1.5-T MR system for the detection of smaller than 1 cm lesions by providing high SNR and CNR.

• Journal of Oral Medicine and Pain
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• v.33 no.2
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• pp.205-218
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• 2008

Interaction between pain and sleep has long been proved through many researches, and various studies are being conducted to identify its mechanism. However, these studies have targeted on patients with systemic disease, such as rheumatic disease and fibromyalgia. There are few researches on patients with orofacial pain including temporomandibular disorder(TMD). In this study, we studied interaction between pain aspect and sleep quality in 229 patients with TMD, who visited the TMJ and Orofacial pain clinic. Pittsburgh Sleep Quality Index(PSQI), Epworth sleepiness scale(ESS) questionnaire were surveyed and sleep-screening device was operated. PSQI showed that sleep quality in TMD patients with pain was poorer than that in TMD patients without pain. The ratio of poor sleeper was higher in TMD patients with pain. Especially, TMD patients with chronic pain showed obviously poorer sleep quality than TMD patients with acute pain. The result of ESS showed that patients with painful TMD showed more daytime sleepiness than painless TMD patients. The ratio of TMD patients with chronic pain who had daytime sleepiness was higher than TMD patients with acute pain, and the amount of daytime sleepiness was higher in the group of chronic pain. In TMD patients with chronic pain, only the poor sleeper(PSQI>5) presented mean ESS>10(diagnostic criteria of daytime sleepiness). There was no correlation between pain intensity and sleep quality or daytime sleepiness. The result of ApnealinkTM for screening of sleep related breathing disorder showed that only 1 patient presented AHI>5 among 19 participants. TMD patients with chronic pain presented poor sleep quality and excessive daytime sleepiness similar to other chronic pain patients. Evaluation of sleep state by questionnaire might be useful for diagnosis and management of TMD, because sleep disturbance decreases pain threshold and pain disturbs sleep. In addition, sleep-screening device would be useful for screening sleep related breathing disorder in dental clinic.

• Tuberculosis and Respiratory Diseases
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• v.59 no.6
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• pp.606-612
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• 2005

Background : It has been reported that nontuberculosis mycobacterium(NTM) isolates account for approximately 10% of patients with a positive Acid-Fast Bacilli(AFB) smear. Therefore, it is necessary to consider NTM pulmonary disease when such a positive test is encountered. The aim of this study was to evaluate the etiologies and clinical characteristics of patients with NTM pulmonary disease who had been treated at a national tuberculosis hospital. Methods : The NTM isolates were recovered from the sputum or bronchial washing specimens submitted to a clinical laboratory of National Masan TB Hospital from August 2002 to July 2003. All samples were identified using a polymerase chain reaction-restriction fragment length polymorphism analysis method, which amplifies the rpoB gene. The patients were diagnosed with NTM disease according to the American Thoracic Society diagnostic criteria. Results : One hundred NTM isolates were recovered from 57 patients. Of the 100 isolates, M. avium complex(MAC) was the most common species, which was found 55%(n=55) of patients, followed by M. abscessus(n=25), and M. fortuitum( n=9). 26(45.6%) patients had NTM disease. Twenty-six (45.6%) patients had NTM disease according to The American Thoracic Society classification. The main organisms involved in NTM disease were MAC(n=19, 73.1%) and M. abscessus(n=5, 19.2%). The pathogenic potential was 67.9% in M. intracellulare and 41.7% in M. abscessus. The predictive factors related to NTM disease were a positive sputum smear (OR 6.4, p=0.02) and the isolation of either MAC or M. abscessus(OR 6.9, p=0.007). Fifteen patients(57.7%) were cured. There were no significant factors associated with the treatment success. Conclusion : There was a relatively high proportion of NTM disease in NTM isolates and the common species were MAC and M. abscessus. The predictive factors for NTM disease were a positive sputum smear and the isolation of either MAC or M. abscessus.

• The Korean Journal of Nuclear Medicine
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• v.34 no.3
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• pp.243-251
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• 2000

Purpose: This prospective study was performed to evaluate the usefulness of preoperative radioimmunoscintigraphy and intraoperative scintimetric examination (radioimmunoguided surgery: RIGS) using $^{99m}Tc-anti-CEA\;F(ab')_2$ fragment. Materials and Methods: Nineteen patients with rectal cancer underwent preoperative whole body planar scintigraphy at 4 hours after injection of $^{99m}Tc-anti-CEA\;F(ab')_2$ fragment and SPECT imaging at 18 hours. Surgical operation was performed at 24 hours after injection. During laparotomy, radioactivities from intraabdominal viscera were measured by gamma probe. The radioactivities from excised tumor and lymph nodes were also measured and compared with pathology. Results: All nineteen patients were confirmed to have adenocarcinomas in the rectum. Twenty-seven of 97 excised lymph node groups had metastasis and 2 patients had liver metastasis in pathology Preoperative radioimmunoscintigraphy detected primary tumors in 11 patients (sensitivity 55%) and it could not detect any lymph nodes or liver metastasis. All patients showed high radioactivity in the kidneys, liver, spleen, and major vessels in intraoperative measurement by gamma probe, and tumor activity was not discriminated from background activity However, radioactivity from excised tumor was higher than normal rectum (T/B ratio; $3.47{\pm}2.25$). When excised lymph node activity/background activity ratio >1.5 was considered as positive criteria of metastasis, sensitivity, specificity, positive and negative predictive values were 78.6%, 73.9%, 55.0% and 89.5%, respectively. Conclusion: Radioimmunoscintigraphy using $^{99m}Tc-anti-CEA\;F(ab')_2$ has no additional value for preoperative staging and use of early RIGS using $^{99m}Tc-anti-CEA\;F(ab')_2$ is inappropriate. For early RIGS using $^{99m}Tc$ labeled antibodies in rectal cancer patients, further development of more specific antibodies and methods to reduce background activity are needed.