• Tuberculosis and Respiratory Diseases
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• v.55 no.1
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• pp.59-68
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• 2003

Background : In intubated patients, cultures of endotracheal aspirates (EA) are apt to contamination throughout the endotracheal tube. Therefore, the identification of etiologic agents via conventional EA cultures is not always reliable. In order to differentiate a pulmonary infection from a non-infectious disease, and to identify the true etiologic agent of acute pulmonary infection, blinded protected specimen brushing (PSB) was used, and its efficacy evaluated. Methods : In 51 intubated patients, with suspected pneumonia, blind PSB were performed, and the results compared with blood and EA cultures. A protected specimen brush was introduced through the endotracheal tube, and settled at the affected large bronchus. A specimen brush was introduced to the expected region using the blind method. The tip of the brush was introduced with an aseptic technique after vigorously mixed for 1 minute in $1cm^3$ of Ringer's lactate solution. The specimens were submitted for quantitative culture within 15 minutes, with a culture being regarded as positive if the colony forming units were above $10^3/ml$. Results : Of the 51 patients, 15 (29.4%) had community-acquired pneumonia (CAP), 27 (52.9%) hospital-acquired pneumonia (HAP) and 9 (17.6%) non-infectious diseases. The sensitivity and specificity of the quantitative PSB culture for the diagnosis of pneumonia were 52.4 and 88.9%, respectively. The sensitivity and specificity of EA were 78.6 and 77.8%, respectively. The blind PSB was superior to the EA for the identification of true etiologic agents. Of 53 episodes of 27 HAP patients, MRSA (Methicillin-resistant staphylococcus aureus) (41.5%) was the most common causative agent followed by Pseudomonas aeruginosa (15.1%), Klebsiella sp. (7.5%) and Acinetobacter sp. (7.5%). Conclusions : As a simple, non-invasive diagnostic modality, the blind PSB is a useful method for the differentiation of a pulmonary infection from non-infectious diseases and to identify the etiologic agents in intubated patients. A blind PSB can be performed without bronchoscopy, so is safer, more convenient and cost-effectiveness for patients where bronchoscopy can not be performed.

• The Korean Journal of Nuclear Medicine
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• v.38 no.3
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• pp.225-232
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• 2004

Purpose : Transient wall motion abnormality and contractile dysfunction of the left ventricle (LV) can be observed in patients with coronary artery disease due to post-stress myocardial stunning. To understand clinical characteristics of stress induced LV dysfunction, we have compared the findings of exercise stress test, myocardial perfusion SPECT and coronary angiography between subjects with and without post-stress LV dysfunction. Materials and Methods : Among subjects who underwent exercise stress test, myocardial perfusion SPECT and coronary angiography within a month of interval, we enrolled 36 patients with post-stress LV election fraction (LVEF) was $\geq5%$ lower than rest (stunning group) and 16 patients with difference of post-stress and rest LVEF was lesser than 1 %(non-stunning group) for this study. Treadmill exercise stress gated myocardial perfusion SPECT was performed with dual head SPECT camera using 740 MBq Tc-99m MIBI and coronary angiography was also performed by conventional Judkins method. Results : Stunning group had a significantly higher incidence of hypercholesterolemia than non-stunning group(45.5 vs. 7.1%, p=0.01). Stunning group also had higher incidence of diabetes mellitus and lower incidence of hypertension, but these were not statistically significant. Stunning group had larger and more severe perfusion defect in stress perfusion myocardial SPECT than non-stunning group(extent 18.2 vs. 9.2%, p=0.029; severity 13.5 vs. 6.9, p=0.040). Stunning group also had higher degree of reversibility of perfusion defect, higher incidence of positive exercise stress test and higher incidence of having severe stenosis ($80{\sim}99%$) in coronary angiography than non-stunning group, but these were not statistically significant. In stunning group, all of 4 patients without perfusion defect had significant coronary artery stenosis and had received revascularization treatment. Conclusion : Patients with post-stress LV dysfunction had larger and more severe perfusion defect and severe coronary artery stenosis than patients without post-stress LV dysfunction. All of the patients without perfusion defect in stunning group had significant coronary artery stenosis and needed revascularization. Therefore, we suggest that invasive diagnostic procedures and therapeutic interventions might be needed in patients with post-stress LV dysfunction.

• Journal of the Korean Society of Radiology
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• v.17 no.3
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• pp.385-392
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• 2023

Caroli's disease is a fibrocystic liver disease. Autosomal recessive disorder is characterized by congenital multiple dilatation of the bile duct. Computerized tomography, magnetic resonance imaging, cholangiography and ultrasound are among the methods for diagnosing caroli disease. Computerized tomography is essential for detecting and distinguishing fibroplastic liver disease and is useful for determining intrahepatic bile duct dilatation. However, awareness of the possible side effects of using contrast mediums is necessary. A typical method of magnetic resonance cholangiography is used for magnetic resonance imaging. A non-invasive examination can reduce the pain of the patient, and the anatomical structure of the bile pancreatic duct and the presence or absence of lesions can be easily and quickly observed. Biliary contrast is an effective diagnostic method that can directly visualize various cystic dilatations throughout the enlarged bile duct. However, since this procedure is also an invasive procedure, it is recommended not for diagnosis but for treatment purposes. Ultrasonography can confirm similar findings to computerized tomography. The hepatic artery root is difficult to prove with conventional grayscale ultrasound. However, it is of clinical value in that it can not only describe dilated bile ducts with vascular roots in the tube but also easily identify color Doppler signals in the tube. With the development of video diagnostics, early diagnosis has become possible through computerized tomography, magnetic resonance imaging, cholangiography, and ultrasound. In order to further contribute to the development of video diagnostics so that long-term prognosis can be improved after treatment through early diagnosis, we examined what aspects of each test's caroli disease appear.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.14 no.2
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• pp.141-147
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• 2011

Purpose: Ultrasonography (US) is widely used as a screening test in patients with abdominal pain (AP). We investigated the usefulness of US by a pediatrician in children with AP. Methods: We retrospectively analysed the medical records of children with AP who undertook US from December, 2008 to July, 2010. Results: A total of 628 patients (325 male, 303 female) were enrolled in this study. The mean age of patients was $8.08{\pm}4.61$ years. Duration of AP was acute in 427 and chronic in 201 patients. Localization of AP was diffuse (36.9%), periumbilical (24.4%), epigastric (21.0%), and right lower quadrant (8.1%). On the examination, there were no abnormal findings in 327 patients (52.1%). Abnormal ultrasonographic findings were mesenteric lymphadenitis (27.1%), intestinal mural thickening (10.0%), intussusception (3.0%), appendicitis (2.6%), choledochal cyst (1.6%), and pancreatitis (0.3%). We performed additional imaging studies such as computed tomography (CT) or magnetic resonance imaging (MRI) in 39 patients who showed obscure findings on the US. In 33 patients (84.6%), the same results were obtained from CT or MRI. Two cases of appendicitis, one case of pancreatitis and one case of Henoch-Sh$\ddot{o}$nlein purpura were diagnosed by the CT examination. However, there were two cases of appendicitis diagnosed by US thathad no evidence of appendicitis on the CT. Diagnostic accuracy of initial US in children with abdominal pain was 99.4%. Conclusion: US by a pediatrician as a screening test in children with AP provides a rapid and accurate diagnostic indication and has non-invasive and radiation-free advantages.

• Investigative Magnetic Resonance Imaging
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• v.12 no.2
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• pp.131-141
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• 2008

Purpose : To investigate the feasibility and accuracy of Proton Resonance Frequency (PRF) shift based magnetic resonance (MR) temperature mapping utilizing the self-developed center array-sequencing phase unwrapping (PU) method for non-invasive temperature monitoring. Materials and Methods : The computer simulation was done on the PU algorithm for performance evaluation before further application to MR thermometry. The MR experiments were conducted in two approaches namely PU experiment, and temperature mapping experiment based on the PU technique with all the image postprocessing implemented in MATLAB. A 1.5T MR scanner employing a knee coil with $T2^*$ GRE (Gradient Recalled Echo) pulse sequence were used throughout the experiments. Various subjects such as water phantom, orange, and agarose gel phantom were used for the assessment of the self-developed PU algorithm. The MR temperature mapping experiment was initially attempted on the agarose gel phantom only with the application of a custom-made thermoregulating water pump as the heating source. Heat was generated to the phantom via hot water circulation whilst temperature variation was observed with T-type thermocouple. The PU program was implemented on the reconstructed wrapped phase images prior to map the temperature distribution of subjects. As the temperature change is directly proportional to the phase difference map, the absolute temperature could be estimated from the summation of the computed temperature difference with the measured ambient temperature of subjects. Results : The PU technique successfully recovered and removed the phase wrapping artifacts on MR phase images with various subjects by producing a smooth and continuous phase map thus producing a more reliable temperature map. Conclusion : This work presented a rapid, and robust self-developed center array-sequencing PU algorithm feasible for the application of MR temperature mapping according to the PRF phase shift property.

• Clinical and Experimental Pediatrics
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• v.45 no.11
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• pp.1381-1388
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• 2002

Purpose : Magnetic resonance cholangiopancreatography(MRCP) is a noninvasive method for imaging the pancreaticobiliary tree. The aim of this study was to evalute the usefulness of MRCP for the diagnosis of pancreaticobiliary diseases in children. Methods : From October 1996 to May 2001, 67 patients with obstructive jaundice and three patients with chronic recurrent pancreatitis were evaluated with abdominal ultrasonography and MRCP. The final diagnosis was based on the operative and pathologic findings with biopsy specimen including clinical and laboratory findings. Results : A total of 70 patients, consisting of 31 males and 39 females, with a mean age of $2.6{\pm}3.3$ years were studied. The final diagnosis was biliary atresia in 25, neonatal cholestasis in 18, choledochal cyst without anomalous pancreatobiliary duct union(APBDU) in nine, choledochal cyst with APBDU in seven, cholestatic hepatitis in five, chronic recurrent pancreatitis in three, sclerosing cholangitis in two, and secondary biliary cirrhosis in one case. The overall diagnostic accuracy of abdominal ultrasonography was 75.7% and that of MRCP was 97.1%. The sensitivity and specificity of MRCP were 100% and 98% for biliary atresia, 87.5% and 100% for choledochal cyst with APBDU, 100% and 100% for choledochal cyst without APBDU, sclerosing cholangitis and chronic recurrent pancreatitis, respectively. Conclusion : MRCP is a fast, non-invasive and reliable method for diagnosing pancreaticobiliary diseases in children and will be the standard diagnostic procedure in the future.

• Journal of radiological science and technology
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• v.29 no.4
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• pp.249-255
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• 2006

Purpose: The diagnostic utility of fluorine-18 2-deoxy-D-glucose positron emission tomograhpy ($^{18}F-FDG $PET) for the non-invasive differentiation of focal lung lesions originated from cancer or inflammation disease by combined visual image interpretation and semi-quantitative uptake value analysis has been documented. In general, Standardized Uptake Value(SUV) is used to diagnose lung disease. But SUV does not contain dynamic information of lung tissue for the glucose. Therefore, this study was undertaken to hypothesis that analysis of dynamic kinetics of focal lung lesions base on $^{18}F-FDG$ PET may more accurately determine the lung disease. So we compared Time Activity Curve(TAC), Standardized Uptake Value-Dynamic Curve(SUV-DC) graph pattern with Glucose Metabolic Rate(MRGlu) from Patlak analysis. Methods: With lung disease, 17 patients were examined. They were injected with $^{18}F-FDG$ over 30-s into peripheral vein while acquisition of the serial transaxial tomographic images were started. For acquisition protocol, we used twelve 10-s, four 30-s, sixteen 60-s, five 300-s and one 900-s frame for 60 mins. Its images were analyzed by visual interpretation TAC, SUV-DC and a kinetic analysis(Patlak analysis). The latter was based on region of interest(ROIs) which were drawn with the lung disease shape. Each optimized patterns were compared with itself. Results: In TAC patterns, it hard to observe cancer type with inflammation disease in early pool blood area but over the time cancer type slope more remarkably increased than inflammation disease. SUV-DC was similar to TAC pattern. In the result of Patlak analysis, In time activity curve of aorta, even though inflammation disease showed higher blood activity than cancer, at first as time went by, blood activity of inflammation disease became the lowest. However, in time activity curve of tissue, cancer had the highest uptake and inflammation disease was in the middle. Conclusion: Through the examination, TAC and SUV-DC could approached the results that lung cancer type and inflammation disease type has it's own difference shape patterns. Also, it has outstanding differentiation between cancer type and inflammation in Patlak and MRGlu analysis. Through these analysis methods, it will helpful to separation lung disease.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.44 no.3
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• pp.1-8
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• 2007

PDiabetic neuropathy is one of the most common diabetes related complications including diabetic nephropathy and retinopahty. In clinical practices, nerve conduction velocity (NCV) has been used as a standard method for diagnosing diabetic neuropathy. However, it applies maximum current of 100mA to nerves causing stress and pain to patients. In this study, as a non-invasive method, $TcpO_2$ was utilized to investigate the difference and relationship between $TcpO_2$ and $SpO_2$ of normal and diabetic neuropathy subjects. In addition, a new method of diagnosing diabetic neuropathy using $TcpO_2$ is suggested. 50 normal subjects and 50 diabetic patients with neuropathy diagnosed by NCV participated in this study. Parameters used in this study were $TcpO_2$, $TcpCO_2$, and $SpO_2$. As a result of the $TcpO_2$ measurements, statistical significances were found from $TcpO_2$ of hands and feet from normal and patients group(p<0.01). $SpO_2$ measured from index finger of normal and patient groups showed no statistical significance(p>0.05). On the other hand, $SpO_2$ measured from great toes of normal and patient groups showed statistical significance(p<0.01). Correlation coefficient between $SpO_2$ of finger and $TcpO_2$ of hand was 0.400 (p<0.01) and $SpO_2$ of toe and $TcpO_2$ of foot was 0.471(p<0.01). Both correlation values were statistically significant. Sensitivities and specificities of the $TcpO_2$ method were found to be 66 % and 92 %, respectively. If the suggested $TcpO_2$ method is used periodically, prevention and early diagnosis of diabetic neuropathy would be possible.

• The Korean Journal of Nuclear Medicine
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• v.34 no.2
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• pp.119-128
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• 2000

Purpose: The aim of this study was to investigate the diagnostic role of $^{99m}Tc$-Tetrofosmin in detection of breast cancer and compared with that of $^{99m}Tc$-MIBI. Material and Methods: Forty-eight patients with a clinically palpable mass or abnormal mammographic or ultrasonographic findings had $^{99m}Tc-MIBI\;and\;^{99m}Tc$-Tetrofosmin scintimammographies after intravenous injection of 925 MBq of radiopharmaceuticals. The scintimammographs were correlated with histopathologic findings. Results: Thirty-three patients were diagnosed with breast cancer and 15 patients with benign breast diseases. The numbers of true positive, true negative, false positive, and false negative cases of $^{99m}Tc$-MIBI scintimammography were 29, 10, 5, and 4 respectively. The sensitivity, specificity, positive predictive value, and negative predictive value of $^{99m}Tc$-MIBI scintimammographies were 87.8%, 66.7%, 85.3%, and 71.4% respectively. The numbers of true positive, true negative, false positive, and false negative cases of $^{99m}Tc$-Tetrofosmin were 31,10, 5, and 2 respectively. The sensitivity, specificity, positive predictive value, negative predictive value of $^{99m}Tc$-Tetrofosmin were 93.9%, 66.7%, 86.1%, and 73.3% respectively. One patient was false negative in both $^{99m}Tc-MIBI\;and\;^{99m}Tc$-Tetrofosmin acintimammographies and its size was 0.5 cm. Conclusion: $^{99m}Tc-Tetrofosmin\;and\;^{99m}Tc-MIBI$ were non-invasive and useful in detection of breast cancer and $^{99m}Tc$-Tetrofosmin was comparable to the $^{99m}Tc$-MIBI in detection of primary breast cancer.

• Journal of the Korean Society of Radiology
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• v.82 no.3
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• pp.654-669
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• 2021

Purpose To evaluate the accuracy of MRI in predicting the pathological complete response (pCR) and the residual tumor size of breast cancer after neoadjucant chemotherapy (NAC), and to determine the factors affecting the accuarcy. Materials and Methods Eighty-eight breast cancer patients who underwent surgery after NAC at our center between 2010 and 2017 were included in this study. pCR was defined as the absence of invasive cancer on pathological evaluation. The maximum diameter of the residual tumor on post-NAC MRI was compared with the tumor size of the surgical specimen measured pathologically. Statistical analysis was performed to elucidate the factors affecting pCR and the residual tumor size-discrepancy between the MRI and the pathological measurements. Results The pCR rate was 10%. The diagnostic accuracy of MRI and the area under the curve for predicting pCR were 90.91% and 0.8017, respectively. The residual tumor sizes obtained using MRI and pathological measurements showed a strong correlation (r = 0.9, p < 0.001), especially in patients with a single mass lesion (p = 0.047). The size discrepancy between MRI and the pathological measurements was significantly greater in patients with the luminal type (p = 0.023) and multifocal tumors/non-mass enhancement on pre-NAC MRI (p = 0.047). Conclusion MRI is an accurate tool for evaluating pCR and residual tumor size in breast cancer patients who receive NAC. Tumor subtype and initial MRI features affect the accuracy of MRI.