• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.7 no.2
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• pp.248-252
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• 2004

Wandering spleen is a rare condition characterized by migration of the spleen from its normal position due to laxity or absence of the supporting splenic ligaments. Ultrasonography shows the absence of the spleen in left upper quadrant (LUQ) and the presentation in the lower abdomen of a homognous mass whose sonographic appearance is consistent with that of a spleen. Contrast-enhanced CT reveals the absence of the spleen in LUQ, a soft tissue mass resembling spleen in the lower abdomen, and the splenic pedicle of whirled appearance. We present a case of wandering spleen, which could be diagnosed with US and CT by the ectopic location of spleen and the whirling pattern of splenic pedicle.

• Journal of Chest Surgery
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• v.22 no.3
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• pp.468-472
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• 1989

Bronchogenic cysts are uncommon congenital lesions which are derived from primitive foregut. Most of the bronchogenic cysts may occur at the tracheal bifurcation, both main bronchi, the lung parenchyme and the mediastinum. We experienced a case of bronchogenic cyst with a esophageal stalk. The diagnosis was made by simple chest x-ray and confirmed by bronchoscopy and chest CT. On the chest CT findings, 6.8X4.8 cm-sized oval shaped mass was located on the right posteroinferior side of the carina, elevating the right main bronchus and the thin wall of the mass was enhanced with contrast materials. On the operative findings, the esophagus and the cyst were connected with a stalk and the cyst was filled with mucinous materials. And on the histological findings, the mass was lined with pseudostratified ciliated columnar epithelium. Thus we report this case of bronchogenic cyst with review of literatures.

• Korean Journal of Radiology
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• v.2 no.2
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• pp.108-112
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• 2001

We report two cases of supratentorial gangliocytomas mimicking an extra-axial tumor. MR imaging indicated that the tumors were extra-axial, and meningiomas were thus initially diagnosed. Relative to gray matter, the tumors were hypointense on T1-weighted images and hyperintense on T2-weighted images. On contrast-enhanced T1-weighted images, homogeneous enhancement was observed, while CT scanning revealed calcification in one of the two cases.

• Journal of Trauma and Injury
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• v.26 no.3
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• pp.74-80
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• 2013

Purpose: There are no detailed reports on the incidence of venous thromboembolism (VTE) in pelvic and acetabular fractures in the Asian population. The purpose of this study was to investigate the incidence of VTE in pelvic and acetabular fractures in the Korean population. Methods: The cases of 67 Korean patients with pelvic and acetabular fractures treated at our hospital from January 2009 to February 2012 were analyzed retrospectively. Until May 2010, VTE screening was performed by contrast-enhanced computed tomography (CT) or ultrasonography (US) when the D-dimer value did not decline predictably, still exceeded $20{\mu}g/ml$ at 5 days after trauma and surgery, or increased to greater than $20{\mu}g/ml$ after a period of decline. After May 2010, contrast-enhanced CT and US were performed routinely irrespective of the D-dimer value. Physical prophylaxis was performed on all patients. The effects of the presence of a pelvic and/or acetabular fracture, and the effects of fracture type, accompanying injuries, and screening strategies on the incidences of VTE were investigated. Results: Overall, 26 patients(38.8%) were diagnosed with VTE and PTE in 14(20.9%). All were asymptomatic. Significantly higher incidences of VTE and PTE were observed in trauma patients with pelvic and acetabular fractures than in trauma patients without pelvic and acetabula fractures treated during the same period. No significant differences were observed in the incidences of VTE and PTE between patients with pelvic fractures, and patients with acetabular fractures or between patients with and without accompanying injuries. Compared with the previous screening strategy, the detection rates for VTE and PTE were higher for the newer screening strategy; however, the difference did not reach statistical significance. Conclusion: In the Korean population, we should be vigilant for a high incidence of VTE, especially PTE, in patients with pelvic and acetabular fractures.

• Tuberculosis and Respiratory Diseases
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• v.76 no.3
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• pp.136-140
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• 2014

Pulmonary artery sarcoma (PAS) is a rare, poorly differentiated malignancy arising from the intimal layer of the pulmonary artery. Contrast-enhanced chest computed tomography (CT) is a good diagnostic modality that shows a low-attenuation filling defect of the pulmonary artery in PAS patients. An 18-year-old man was referred to our hospital for the evaluation and management of cavitary pulmonary lesions that did not respond to treatment. A contrast-enhanced CT of the chest was performed, which showed a filling defect within the right interlobar pulmonary artery. The patient underwent a curative right pneumonectomy after confirmation of PAS. Although lung parenchymal lesions of PAS are generally nonspecific, it can be presented as cavities indicate pulmonary infarcts. Clinicians must consider the possibility of PAS as well as pulmonary thromboembolism in patients with pulmonary infarcts. So, we report the case with PAS that was diagnosed during the evaluation of cavitary pulmonary lesions and reviewed the literatures.

• Korean Journal of Radiology
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• v.22 no.5
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• pp.714-724
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• 2021

Objective: To evaluate the value of ¹⁸F-fluorodeoxyglucose PET/MRI added to contrast-enhanced CT (CECT) in initial staging, assessment of resectability, and postoperative follow-up of biliary tract cancer. Materials and Methods: This retrospective study included 100 patients (initial workup [n = 65] and postoperative follow-up [n = 35]) who had undergone PET/MRI and CECT for bile duct or gallbladder lesions between January 2013 and March 2020. Two radiologists independently reviewed the CECT imaging set and CECT plus PET/MRI set to determine the likelihood of malignancy, local and overall resectability, and distant metastasis in the initial workup group, and local recurrence and distant metastasis in the follow-up group. Diagnostic performances of the two imaging sets were compared using clinical-surgical-pathologic findings as standards of reference. Results: The diagnostic performance of CECT significantly improved after the addition of PET/MRI for liver metastasis (area under the receiver operating characteristic curve [A_z]: 0.77 vs. 0.91 [p = 0.027] for reviewer 1; 0.76 vs. 0.92 [p = 0.021] for reviewer 2), lymph node metastasis (0.73 vs. 0.92 [p = 0.004]; 0.81 vs. 0.92 [p = 0.023]), and overall resectability (0.79 vs. 0.92 [p = 0.007]; 0.82 vs. 0.94 [p = 0.021]) in the initial workup group. In the follow-up group, the diagnostic performance of CECT plus PET/MRI was significantly higher than that of CECT imaging for local recurrence (0.81 vs. 1.00 [p = 0.029]; 0.82 vs. 0.94 [p = 0.045]). Conclusion: PET/MRI may add value to CECT in patients with biliary tract cancer both in the initial workup for staging and determination of overall resectability and in follow-up for local recurrence.

• Tuberculosis and Respiratory Diseases
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• v.63 no.2
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• pp.178-182
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• 2007

A venous air embolism is a complication of various venous access procedures such as contrast-enhanced computed tomography (CECT). Although most cases of iatrogenic venous air embolisms during CECT involve a few milliliters of air and are asymptomatic, a massive venous air embolism can be fatal. We report a case of a massive intraventricular air embolism after CECT with a review of the literature regarding the pathophysiology and treatment of air embolisms.

• Clinical Pain
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• v.20 no.1
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• pp.39-42
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• 2021

A 29-year-old woman had 1-month history of back pain radiating into lower extremities, motor weakness, and sensory abnormalities in both lower extremities. Contrast-enhanced spinal magnetic resonance imaging (MRI) revealed a homogeneously enhancing mass at the T12~L1 and several intradural enhancing nodular lesions at L2~S1. Tumor resection surgery was performed and following histological examination showed that the tumor satisfied the diagnostic criteria for atypical choroid plexus papilloma (CPP). To find primary tumor sites, contrast-enhanced brain MRI, whole spine MRI, and PET-CT were carried out and additional lesions were detected at the fourth ventricle, right cerebellum, and upper thoracic spinal cord. This is a very rare case of metastatic atypical CPP that involves brain, upper thoracic spinal cord, and cauda equina with initial manifestation of radicular symptoms without clinical signs of primary brain lesion.

• Korean Journal of Radiology
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• v.24 no.4
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• pp.294-304
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• 2023

Objective: We aimed to investigate whether image standardization using deep learning-based computed tomography (CT) image conversion would improve the performance of deep learning-based automated hepatic segmentation across various reconstruction methods. Materials and Methods: We collected contrast-enhanced dual-energy CT of the abdomen that was obtained using various reconstruction methods, including filtered back projection, iterative reconstruction, optimum contrast, and monoenergetic images with 40, 60, and 80 keV. A deep learning based image conversion algorithm was developed to standardize the CT images using 142 CT examinations (128 for training and 14 for tuning). A separate set of 43 CT examinations from 42 patients (mean age, 10.1 years) was used as the test data. A commercial software program (MEDIP PRO v2.0.0.0, MEDICALIP Co. Ltd.) based on 2D U-NET was used to create liver segmentation masks with liver volume. The original 80 keV images were used as the ground truth. We used the paired t-test to compare the segmentation performance in the Dice similarity coefficient (DSC) and difference ratio of the liver volume relative to the ground truth volume before and after image standardization. The concordance correlation coefficient (CCC) was used to assess the agreement between the segmented liver volume and ground-truth volume. Results: The original CT images showed variable and poor segmentation performances. The standardized images achieved significantly higher DSCs for liver segmentation than the original images (DSC [original, 5.40%-91.27%] vs. [standardized, 93.16%-96.74%], all P < 0.001). The difference ratio of liver volume also decreased significantly after image conversion (original, 9.84%-91.37% vs. standardized, 1.99%-4.41%). In all protocols, CCCs improved after image conversion (original, -0.006-0.964 vs. standardized, 0.990-0.998). Conclusion: Deep learning-based CT image standardization can improve the performance of automated hepatic segmentation using CT images reconstructed using various methods. Deep learning-based CT image conversion may have the potential to improve the generalizability of the segmentation network.

• Investigative Magnetic Resonance Imaging
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• v.25 no.4
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• pp.313-322
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• 2021

Purpose: To find diagnostic image features, to compare diagnostic performance of multiphase CT versus gadoxetic acid disodium-enhanced MRI (GAD-MRI), and to evaluate the impact of analyzing Liver Imaging Reporting and Data System (LI-RADS) imaging features, for distinguishing combined hepatocellular-cholangiocarcinoma (CHC) from hepatocellular carcinoma (HCC). Materials and Methods: Ninety-six patients with pathologically proven CHC (n = 48) or HCC (n = 48), diagnosed June 2008 to May 2018 were retrospectively analyzed in random order by three radiologists with different experience levels. In the first analysis, the readers independently determined the probability of CHC based on their own knowledge and experiences. In the second analysis, they evaluated imaging features defined in LI-RADS 2018. Area under the curve (AUC) values for CHC diagnosis were compared between CT and MRI, and between the first and second analyses. Interobserver agreement was assessed using Cohen's weighted κ values. Results: Targetoid LR-M image features showed better specificities and positive predictive values (PPV) than the others. Among them, rim arterial phase hyperenhancement had the highest specificity and PPV. Average sensitivity, specificity, and AUC values were higher for MRI than for CT in both the first (P = 0.008, 0.005, 0.002, respectively) and second (P = 0.017, 0.026, 0.036) analyses. Interobserver agreements were higher for MRI in both analyses (κ = 0.307 for CT, κ = 0.332 for MRI in the first analysis; κ = 0.467 for CT, κ = 0.531 for MRI in the second analysis), with greater agreement in the second analysis for both CT (P = 0.001) and MRI (P < 0.001). Conclusion: Rim arterial phase hyperenhancement on GAD-MRI can be a good indicator suggesting CHC more than HCC. GAD-MRI may provide greater accuracy than CT for distinguishing CHC from HCC. Interobserver agreement can be improved for both CT and MRI by analyzing LI-RADS imaging features.