• Korean Journal of Radiology
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• v.20 no.1
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• pp.50-57
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• 2019

In pediatric thoracic CT, respiratory motion is generally treated as a motion artifact degrading the image quality. Conversely, respiratory motion in the thorax can be used to answer important clinical questions, that cannot be assessed adequately via conventional static thoracic CT, by utilizing four-dimensional (4D) CT. However, clinical experiences of 4D thoracic CT are quite limited. In order to use 4D thoracic CT properly, imagers should understand imaging techniques, radiation dose optimization methods, and normal as well as typical abnormal imaging appearances. In this article, the imaging techniques of pediatric thoracic 4D CT are reviewed with an emphasis on radiation dose. In addition, several clinical applications of pediatric 4D thoracic CT are addressed in various thoracic functional abnormalities, including upper airway obstruction, tracheobronchomalacia, pulmonary air trapping, abnormal diaphragmatic motion, and tumor invasion. One may further explore the clinical usefulness of 4D thoracic CT in free-breathing children, which can enrich one's clinical practice.

• Journal of Chest Surgery
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• v.50 no.5
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• pp.403-406
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• 2017

Tracheobronchial rupture due to blunt chest trauma is a rare but life-threatening injury in the pediatric population. Computed tomography (CT) is not always reliable in the management of these patients. An additional concern is that ventilation may be disrupted during surgical repair of these injuries. This report presents the case of a 4 -year-old boy with an injury to the lower trachea and carina due to blunt force trauma that was missed on the initial CT scan. During surgery, he was administered venoarterial extracorporeal membrane oxygenation (ECMO). Although ECMO is not generally used in children, this case demonstrated that the short-term use of ECMO during pediatric surgery is safe and can prevent intraoperative desaturation.

• Korean Journal of Radiology
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• v.22 no.8
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• pp.1397-1415
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• 2021

The use of pediatric cardiothoracic CT for congenital heart disease (CHD) was traditionally limited to the morphologic evaluation of the extracardiac thoracic vessels, lungs, and airways. Currently, the applications of CT have increased, owing to technological advancements in hardware and software as well as several dose-reduction measures. In the previously published part 1 of the guideline by the Asian Society of Cardiovascular Imaging Congenital Heart Disease Study Group, we reviewed the prerequisite technical knowledge for clinical applications in a user-friendly and vendor-specific manner. Herein, we present the second part of our guideline on contemporary clinical applications of pediatric cardiothoracic CT for CHD based on the consensus of experts from the Asian Society of Cardiovascular Imaging CHD Study Group. This guideline describes up-to-date clinical applications effectively in a systematic fashion.

• Journal of Trauma and Injury
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• v.18 no.2
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• pp.119-126
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• 2005

Background: Blunt thoracic trauma in children has a high morbidity and mortality. In this study, we assessed the significance of the injury pattern, mechanism and initial status in emergency department on severity and prognosis in pediatric blunt thoracic trauma patients. Method: We retrospectively reviewed medical records and chest X-ray and CT images of 111 pediatric blunt thoracic trauma patients from October 2000 to June 2005. Data recorded age, gender, season, injury mechanism, injury pattern, associated injury, length of hospital stay and cause of death. Result: Of all 111 patients, 68 patients were injured by motor vehicle accidents, 30 were falls, 5 were motorcycle accidents, 3 were sports accidents and 5 were miscellaneous. In thoracic trauma, single injury of lung contusion were 35 patients and 32 patients had multiple thoracic injuries. Hospital stay in school age group were longer than preschool age group. The causes of death were brain injury in 9, respiratory distress in 4, and hypovolemic shock in 2 patients. Emergently transfused and mechanically ventilated patients had higher mortality rates than other patients. Patients required emergency operation and patients with multiple thoracic injuries had higher mortality rates. Conclusion: In this study, patients with combined injury, emergency transfusion, mechanical ventilation, emergency operation, multiple injuries in chest X-ray had higher mortality rates. Therefore in these pediatric blunt thoracic trauma patients, accurate initial diagnosis and proper management is required.

• Journal of the Korean Society of Radiology
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• v.13 no.6
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• pp.879-887
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• 2019

The purpose of this study is to establish a physiological injection protocol according to body weight, in order to minimize amount of contrast medium and optimize contrast enhancement in pediatric patients performing thoracic CT examinations. The 80 pediatric patients under the age of 10 were studied. Intravenous contrast material containing 300 mgI/ml was used. The group A injected with a capacity of 1.5 times its weight, and groups B, C and D added 5 to 15 ml of normal saline with a 10% decrease in each. The physiologic model which can be calculated by weight about amount of injection of contrast medium and normal saline, flow rate and delay time were applied. To assess image quality, measured average HU value and SNR of superior vena cava, pulmonary artery, ascending and descending aorta, right and left atrium, right and left ventricle. CT numbers of subclavian vein and superior vena cava were compared to identify the effects of reducing artifacts due to normal saline. Comparing SNR according to the contrast medium injection protocol, significant differences were found in superior vena cava and pulmonary artery, descending aorta, right and left ventricle, and CT numbers showed significant differences in all organs. In particular, B group with a 10% decrease in contrast medium and an additional injection of saline showed a low degree of contrast enhancement in groups with a decrease of more than 20%. In addition, the group injected with normal saline greatly reduced contrast enhancement of subclavian vein and superior vena cava, and the beam hardening artifact by contrast medium was significantly attenuated. In conclusion, the application of physiological protocol for injection of contrast medium in pediatric thoracic CT examinations was able to reduce artifacts by contrast medium, prevent unnecessary use of contrast medium and improve the effect of contrast enhancement.

• Korean Journal of Radiology
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• v.23 no.9
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• pp.854-865
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• 2022

Photon-counting detector (PCD) CT is a new CT technology utilizing a direct conversion X-ray detector, where incident X-ray photon energies are directly recorded as electronical signals. The design of the photon-counting detector itself facilitates improvements in spatial resolution (via smaller detector pixel design) and iodine signal (via count weighting) while still permitting multi-energy imaging. PCD-CT can eliminate electronic noise and reduce artifacts due to the use of energy thresholds. Improved dose efficiency is important for low dose CT and pediatric imaging. The ultra-high spatial resolution of PCD-CT design permits lower dose scanning for all body regions and is particularly helpful in identifying important imaging findings in thoracic and musculoskeletal CT. Improved iodine signal may be helpful for low contrast tasks in abdominal imaging. Virtual monoenergetic images and material classification will assist with numerous diagnostic tasks in abdominal, musculoskeletal, and cardiovascular imaging. Dual-source PCD-CT permits multi-energy CT images of the heart and coronary arteries at high temporal resolution. In this special review article, we review the clinical benefits of this technology across a wide variety of radiological subspecialties.

• Journal of Chest Surgery
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• v.50 no.2
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• pp.71-77
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• 2017

Background: Cardiac computed tomography (CT) has emerged as an alternative to magnetic resonance imaging (MRI) for ventricular volumetry. However, the clinical use of cardiac CT requires external validation. Methods: Both cardiac CT and MRI were performed prior to pulmonary valve implantation (PVI) in 11 patients (median age, 19 years) who had undergone total correction of tetralogy of Fallot during infancy. The simplified contouring method (MRI) and semiautomatic 3-dimensional region-growing method (CT) were used to measure ventricular volumes. Results: All volumetric indices measured by CT and MRI generally correlated well with each other, except for the left ventricular end-systolic volume index (LV-ESVI), which showed the following correlations with the other indices: the right ventricular end-diastolic volume index (RV-EDVI) (r=0.88, p<0.001), the right ventricular end-systolic volume index (RV-ESVI) (r=0.84, p=0.001), the left ventricular end-diastolic volume index (LV-EDVI) (r=0.90, p=0.001), and the LV-ESVI (r=0.55, p=0.079). While the EDVIs measured by CT were significantly larger than those measured by MRI (median RV-EDVI: $197mL/m^2$ vs. $175mL/m^2$, p=0.008; median LV-EDVI: $94mL/m^2$ vs. $92mL/m^2$, p=0.026), no significant differences were found for the RV-ESVI or LV-ESVI. Conclusion: The EDVIs measured by cardiac CT were greater than those measured by MRI, whereas the ESVIs measured by CT and MRI were comparable. The volumetric characteristics of these 2 diagnostic modalities should be taken into account when indications for late PVI after tetralogy of Fallot repair are assessed.

• Advances in pediatric surgery
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• v.13 no.1
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• pp.87-92
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• 2007

An 1-month old female newborn was admitted to our hospital because of jaundice which occurred at 2 days after birth. Plain chest X-ray and chest CT revealed a collapsed right middle lobe and lobar emphysema was suspected. Right upper lobectomy of the lung was done and pathologic findings showed an infantile lobar emphysema. After the operation, the newborn was discharged without complication and was followed up through the out patient clinic. Infantile lobar emphysema is rare and male dominant. Left upper lobe of the lung is the most prevalent site. Patients with infantile lobar emphysema complain of respiratory symptoms. We report one case of infantile lobar emphysema on right upper lobe of lung, in a female with no respiratory symptoms.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.12 no.2
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• pp.246-250
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• 2009

Congenital diaphragmatic hernias (CDH) usually cause respiratory distress soon after birth and are associated with a high mortality rate in the early postnatal period. However, there is a milder form of CDH that does not manifest during the neonatal period. The late presenting CDH is characterized by a variable clinical picture. We present the case of an otherwise healthy 5-month-old girl, who was referred for evaluation of an 1-day history of vomiting and irritability. Chest simple X-ray and CT showed bowel loops in the left thoracic cavity, which was consistent with diaphragmatic hernia. At operation, she was found to have a small left posterolateral diaphagmatic defect with viable small bowel loops in the left thoracic cavity. After surgical reposition of the hernia, the symptoms such as vomiting and irritability subsided. The lack of typical manifestation of CDH such as respiratory distress may lead to delayed diagnosis. The possibility of late presenting CDH should not be overlooked even after the neonatal period.

• Advances in pediatric surgery
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• v.16 no.2
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• pp.154-161
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• 2010

Pulmonary sequestration (PS) is a rare congenital malformation of the lower respiratory tract. The anomaly is characterized by absence of communication with the tracheobronchial tree and isolated blood supply from an anomalous systemic vessels. With the utilization of antenatal ultrasound, the diagnosis of asymptomatic neonatal PS has increased. Treatment options include observation, arterial embolization and surgical resection. The aim of the present study is to review the clinical course of PS and to share our experience with thoracoscopic resection. A total of 96 patients with PS were treated at Asan Children's Hospital between 1999 and 2010. The diagnosis of PS was established by CT in the cases managed by observation or embolization, and by tissue pathology in the surgical cases. Medical records and radiographic images were retrospectively reviewed. Thirty-nine patients were managed by embolization and 30 patients by surgery. The remaining 27 patients have been under observation without any procedures. Among 27 observation patients, 1 patient regressed completely and 10 patients were lost to follow up. Of the 39 embolizations patients, 2 had their lesion regress and sepsis was suspected after embolization. In 1 patient, the microcoil migrated to the iliac artery during the embolization procedure, and another patient developed renal abscess caused by renal artery embolization. Among 30 surgical cases, resection by thoracotomy was performed in 27 at the Department of Thoracic Surgery, and thoracoscopic resection in 3 at the Division of Pediatric Sugery. Only one wound complication ocurred. We conclud that surgical excision should be recommended for pulmonary sequestration, whether the sequestration is symptomatic or not because of the risk of infection, the low rate of natural regress, poor compliance, severe complications after embolization, and to exclude other pathology. In summary, thoracoscopic resection of the pulmonary sequestration is feasible, efficacious, safe and cosmetically superior even in neonatal period.