Authors retrospectively analyzed the CT findings of cystic tumors of the mediastinum in surgically confirmed13 cases at Seoul National University Hospital during the recent 3 years from August 1980 to August 1983. Theresults are as follows: 1. Among 13 cases, bronchogenic cyst and cystic teratoma were 4 cases respectively,pericardial cyst were 2 cases, and thymic cyst and cystic hygroma was 1 case respectively. 2. CT No. of 4bronchogenic cysts was in the range of 12-112 HU, 3 cases among them had thick-walled capsules. CT No. of 4 cysticteratomas was in the range of
Bronchogenic Cyst ; Capsules ; Diagnosis, Differential ; Lymphangioma, Cystic ; Mediastinal Cyst ; Mediastinum ; Retrospective Studies ; Seoul ; Teratoma

No abstract available.
Anemia, Aplastic*

No abstract available.
Neuroblastoma*

No abstract available.
Child* ; Humans

PURPOSE: To determine the accuracy of automated computer aided volumetry for simulated small pulmonary nodules at computed tomography using various types of phantoms MATERIALS AND METHODS: Three sets of synthetic nodules (small, calcified and those adjacent to vessels) were studied. The volume of the nodules in each set was already known, and using multi-slice CT, volumetric data for each nodule was acquired from the three-dimensional reconstructed image. The volume was calculated by applying three different threshold values using Rapidia(R) software (3D-Med, Seoul, Korea). RESULTS: Relative errors in the measured volume of synthetic pulmonary nodules were 17.3, 2.9, and 11.5% at -200, -400, and -600 HU, respectively, and there was good correlation between true volume and measured volume at -400 HU (r=0.96, p<0.001). For calcified nodules, relative errors in measured volume were 10.9, 5.3, and 16.5% at -200, -400, and -600 HU, respectively, and there was good correlation between true volume and measured volume at -400 HU (r=1.03, p<0.001). In cases involving synthetic nodules adjacent to vessels, relative errors were 4.6, 16.3, and 31.2 % at -200, -400, and -600 HU, respectively. There was good correlation between true volume and measured volume at -200 HU (r=1.1, p<0.001). CONCLUSION: Using computer-aided volumetry, the measured volumes of synthetic nodules correlated closely with their true volume. Measured volumes were the same at each threshold level, regardless of window setting.
Cone-Beam Computed Tomography ; Seoul

No abstract available.
Anemia, Hypoplastic, Congenital*

No abstract available.
Humans ; Wilms Tumor*

Malignant lymphomas with cental and/or peripheral low densities suggesting internal infarcted necrosis arerare, probably due to the same reason as that of normal lymph nodes in which spontaneous infarction seldom occuresbecause of dual vascular connection and low oxygen consumption of activated lymphocytes. We report eight cases ofhistologically proven non-Hodgkin's lymphoma, that showed necrotic low density within tumor mass in CT scan, priorto any teatment. The locations of necrotic lymphomas were mediastinum in 3 cases, abdomen in 4 cases, and neck in1 case. The histologic types of the cases wre diffuse histiocytic (Rappaport) in 4 cases, porly differentiatedlymphocytic types in 2 cases, lymphoblastic type in 1 case, and mixed type(predominantly poorly differentiatedlymphocytic) in 1 case. It seems that malignant lymphoma can be included in differential diagnosis oflymphadenopathy with cental and/or peripheral necrotic low densities on CT.
Abdomen ; Diagnosis, Differential ; Infarction ; Lymph Nodes ; Lymphocytes ; Lymphoma ; Lymphoma, Non-Hodgkin ; Mediastinum ; Neck ; Necrosis ; Oxygen Consumption ; Tomography, X-Ray Computed

PURPOSE: Thoracic ultrasonography (US) is an emerging tool for diagnosing pneumothorax (PTX), and the possible application of color Doppler to ultrasonography is another new development. The aim of this study is to analyze the possible contribution of color Doppler to thoracic US and to the estimation of pneumothorax volume. METHODS: Patients who were admitted to emergency department underwent chest X-ray and thoracic US with color Doppler. They were also evaluated by computed tomography, if needed, US was performed at four chest sites by emergency medicine faculty and resident, and concordance between color Doppler and lung sliding was analyzed. The number of sites with abnormal findings was correlated with the volume of PTX at each sites. Statistical analysis was performed with Pearson correlation. RESULTS: Sixty-three of 151 PTX cases were included in our study. The sensitivity of US was for PTX detection was 92.1% (58 of 63), and the concordance between color Doppler and lung sliding was 99.4%. The number of sites per patient with abnormal findings increased with the average volume of the PTX. The average PTX volume in the 5 cases with normal findings was 7.0%, which is a smallsized PTX. CONCLUSION: The use of color Doppler is not more accurate than lung sliding, but it may helpful in diagnosing PTX. The volume of a PTX is proportional to a patient's number of sites with abnormal US findings.
Emergency Medicine ; Emergency Service, Hospital ; Humans ; Lung ; Pneumothorax* ; Thorax ; Ultrasonography

PURPOSE: This study aimed to identify the best way of developing equivalent item sets and to propose a stable and effective management plan for periodical licensing examinations. METHODS: Five pre-equated item sets were developed based on the predicted correct answer rate of each item using linear programming. These pre-equated item sets were compared to the ones that were developed with a random item selection method based on the actual correct answer rate (ACAR) and difficulty from item response theory (IRT). The results with and without common items were also compared in the same way. ACAR and the IRT difficulty were used to determine whether there was a significant difference between the pre-equating conditions. RESULTS: There was a statistically significant difference in IRT difficulty among the results from different pre-equated conditions. The predicted correct answer rate was divided using 2 or 3 difficulty categories, and the ACAR and IRT difficulty parameters of the 5 item sets were equally constructed. Comparing the item set conditions with and without common items, including common items did not make a significant contribution to the equating of the 5 item sets. CONCLUSION: This study suggested that the linear programming method is applicable to construct equated-item sets that reflect each content area. The suggested best method to construct equated item sets is to divide the predicted correct answer rate using 2 or 3 difficulty categories, regardless of common items. If pre-equated item sets are required to construct a test based on the actual data, several methods should be considered by simulation studies to determine which is optimal before administering a real test.
Licensure ; Methods ; Programming, Linear