[en] We had experienced 5 cases of angiographically occult AVMs led to intracerebral hemorrhage and progressive neurologic deficit and seizure. Cerebral angiography in each case failed to demonstrate the vascular nature of the lesion and conventional skull radiography was no use. Computed tomography (CT), in 4 cases out of 5, showed well demarcated, slightly hyperdense and ovoid masses which turned out resolving hematomas. These lesions had also contained focal areas of high densities. In one case we observed definitively enhanced area in the resolving hematoma and it was corresponded to histopathologically proved AVM. CT appearance of acute hemorrhage at the subcortical region of cerebral hemisphere was showed in another case. We believe that CT can afford important supplementary information regarding an associated hematoma for angiographically occult AVM. Caution is advised in assuming that angiographically avascular lesion demonstrable by CT is not vascular malformation.

[en] To present CT findings of benign mass-like nodular lesions associated with chronic tuberculous empyema. We retrospectively reviewed the CT scans of nine patients with mass-like lesions associated with chronic tuberculous empyema, which were pathologically (operation=4, US-guided biopsy=3) or clinically (n=2) confirmed as benign lesions. Shape, number, size, presence of calcification and enhancement pattern of mass-like lesions were assessed. In all patients, chest CT showed unilateral calcified pleural thickening, with mass-like nodular lesions. Fluid within the pleural cavity was observed in eight patients, CT findings of mass-like lesions were multiple and nodular (n=9). Calcification was demonstrated within the lesions in four patients. In each case, the size of the largest nodules was 1-3 cm in diameter. In contrast, CT showed mild (n=6) to moderate (n=2) enhancement compared with adjacent muscles. The pathologic results of mass-like lesions were chronic inflammation (n=3) and necrosis (n=4). Benign mass-like lesions associated with chronic tuberculous empyema appeared as multiple nodules varying in size from 1 to 3 cm in diamter, with slight enhancement

[en] To date, the high spatial frequency algorithm (HSFA) which reduces image smoothing and increases spatial resolution has been used for the evaluation of parenchymal lung diseases in thin-section high-resolution CT. In this study, we compared the ultrahigh spatial frequency algorithm (UHSFA) with the high spatial frequency algorithm in the assessment of thin section images of the lung parenchyma. Three radiologists compared the UHSFA and HSFA on identical CT images in a line-pair resolution phantom, one lung specimen, 2 patients with normal lung and 18 patients with abnormal lung parenchyma. Scanning of a line-pair resolution phantom demonstrated no difference in resolution between two techniques but it showed that outer lines of the line pairs with maximal resolution looked thicker on UHSFA than those on HSFA. Lung parenchymal detail with UHSFA was judged equal or superior to HSFA in 95% of images. Lung parenchymal sharpness was improved with UHSFA in all images. Although UHSFA resulted in an increase in visible noise, observers did not found that image noise interfered with image interpretation. The visual CT attenuation of normal lung parenchyma is minimally increased in images with HSFA. The overall visual preference of the images reconstructed on UHSFA was considered equal to or greater than that of those reconstructed on HSFA in 78% of images. The ultrahigh spatial frequency algorithm improved the overall visual quality of the images in pulmonary parenchymal high-resolution CT

[en] To describe HRCT findings in five patients with pathologically proved acute interstitial pneumonia. This study included 5 patients with pathological and clinical diagnosis of acute interstitial pneumonia. Mean age of the patients was 40 (range, 31-53 years). CT scans were reviewed by two chest radiologists retrospectively. CT scans were assessed for the presence and distribution of ground-glass attenuation, air-space consolidation, interlobular septal thickening, honeycombing, and pleural effusion. The area of ground-glass attenuation and air-space consolidation were seen at HRCT in all 5 patients. These lesions were distributed diffusely in both lungs, but involved predominantly subpleural lungs in 2 patients and posterior lungs in 3 patients. Three patients and mild interlobular septal thickening. None of them showed honeycombing. Three of the 5 patients died within 52 days of initial manifestation. Acute interstitial pneumonia differs from the more chronic form of idiopathic interstitial pneumonia in their HRCT findings

[en] The purpose of this study was to evaluate. the high-resolution CT features of Swyer-James syndrome with special attention to the airway lesions and to determine the clinical utility of high-resolution CT compared with that of chest radiography. In seven patients with Swyer-James syndrome, we retrospectively reviewed chest radiographs obtained during inspiration and expiration and high-resolution CT scans obtained in inspiration. The high-resolution CT appearance was evaluated and compared with that of chest radiography. On both chest radiographs and high-resolution CT, the affected lung volume was relatively diminished in four patients and normal in three patients. In all seven patients, chest radiographs showed hyperlucency of the lung which was unilateral in four and bilateral in three patients. Unilateral small hilum was seen in six patients and bronchiectasis was demonstrated in one patient on chest radiographs. The hyper lucent lung volume was not diminished on expiratory radiographs in all seven patients. In all patients, high-resolution CT demonstrated low attenuation regions of the lung either bilaterally(n=5) or unilaterally(n=2). Pulmonary vessels were markedly decreased in size and number in the lung parenchyma with low attenuation. Six patients had bronchiectasis on high-resolution CT, which were cylindrical or varicose in five and cystic in one. Bronchiolectasis was observed in three patients on high-resolution CT. The high-resolution CT findings are characteristic of Swyer-James syndrome. High-resolution CT is more sensitive than chest radiography in detecting regions of low attenuation and bronchiectasis and may be useful for the diagnosis of Swyer-James syndrome. Our results suggest that bronchiectasis is a frequently associated airway lesion of Swyer-James syndrome and bronchiolectasis may be associated in some cases

[en] Contrast-enhanced 3-D ultrafast MR angiography is a widely accepted MR imaging technique for the evaluation of the carotid artery, aorta, renal artery, mesenteric artery and portal venous system. To estimate its clinical usefulness, single- and double- dose contrast-enhanced 3-D ultrafast pulmonary MR angiography was assessed after a timing examination was performed. Twenty volunteers underwent gadolinium-enhanced ultrafast pulmonary MR angiography (3-D FISP, TR[msec]/TE[msec] = 5.0/2.0, with 25 deg flip angel). In ten volunteers(single-dose injection group) pulmonary MR angiography was performed after the administration of 0.1 mmol/kg(single dose injection group), while the other ten(double-dose injection group) each received, prior to angiography, 0.2 mmol/kg. In all cases, a timing examination was performed during axial turbo-FLASH imaging(TR/TE/TI 8.5/4.0/100, 10 deg flip angle) after injection of the same dose as that used for subsequent contrast-enhanced pulmonary MR angiography. In both groups, overall image quality, pulmonary artery visibility and contrast-to-noise ratio of the pulmonary artery were assessed on the basis of images obtained. With regard to overall image quality, there was no significant statistical difference between the two groups (P>0.05), and in both, depiction of the central and lobar pulmonary artery was excellent. As regards depiction of the segmental artery, the average grading of the single dose injection group was 2.83 ± 0.32, that of the double dose injection group was 2.85 ± 0.3, with no statistical significance (P>0.05). With respect to contrast-to-noise ratio of the central, lobar, and segmental arteries, the best results were obtained by the double dose injection group(P<0.05). Although the contrast-to-noise ratio in the double-dose injection group was better than that in the single-dose group, differences in overall image quality and pulmonary artery depiction were not statistically significant. Thus, single-dose, contrast-enhanced 3-D ultrafast pulmonary MR angiography can provide useful images in clinical trials

[en] Endobronchial tuberculosis and bronchogenic cancer are common causes of atelectasis or obstructive pneumonitis in Korea. Differentiation between endobronchial tuberculosis and bronchogenic carcinoma is important for the treatment and prognosis but it is sometimes difficult to differentiate these two lesions with radiologic examinations. The purpose of this study was to find the differential points between endobronchial tuberculosis and bronchogenic carcinoma associated with atelectasis or obstructive pneumonitis. Forty patients in whom atelectasis or obstructive pneumonitis was detected on chest radiographs comprised the study. A definite mass opacity was not observed on chest radiographs in all patients. In these patients, the causes of obstruction were endobronchial tuberculosis (n = 20) and bronchogenic cancer (n = 20) which were microbiologically or pathologically confirmed. Double obstructive lesions were more frequently found in endobronchial tuberculosis (8/20) than in bronchogenic cancer (1/20). Multiple calcification along the bronchial wall and severe distortion of bronchi were observed only in endobronchial tuberculosis (4/20) and associated low density mass at obstruction site was only observed in bronchogenic cancer (6/20). Bronchial dilatation (11/20) and parenchymal calcifications (14/20) distal to obstruction site, air containing bronchogram at post obstructive bronchus (14/20) were more frequently found in endobronchial tuberculosis. Contour bulging at obstruction site (14/20), and only mucus bronchogram at post obstructive bronchus (14/20) were more frequently found in bronchogenic carcinoma. In patients with atelectasis or obstructive pneumonitis, endobronchial tuberculosis is characterized by double obstructive lesion, multiple calcifications at the bronchial wall, and severe distortion of the bronchi. Endobronchial carcinoma is characterized by a low density mass at the obstructive site

[en] The purpose of this study is to evaluate the diagnostic accuracy of CT in the differential diagnosis of tuberculous and malignant pleural effusion whether or not lung lesions are present, and to investigate the CT findings used for this differential diagnosis. This study involved 30 patients with tuberculous pleural effusion (mean age, 44.6 years; M : F = 19:11) and 20 with malignant pleural effusion (mean age, 57.2 years; M: F=10:10). All 50 patients underwent enhanced CT chest scans, and the respective conditions were pathologically confirmed. Two radiologists unaware of the pathologic results and distributions of patients reviewed these scans, CT findings of pleural effusions, their diagnoses, and the degree of confidence of their diagnoses. In most cases, CT provided correct differential diagnosis between tuberculous and malignant pleural effusion. It can help determine the nature of associated lung and pleural lesions, and specific findings of the latter, and can accurately differentiate tuberculous and malignant pleural effusion. (author). 20 refs., 3 tabs., 5 figs

[en] Plexiform neurofibroma usually occur in the neck, pelvis and extremities, but they may seen virtually at any location, including the thorax. To evaluate the findings and the role of CT in plexiform neurofibromatosis of the mediastinum. We retrospectively reviewed the clinical results and thoracic CT scans of five patients with pathologically proved plexiform neurofibromatosis of the mediastinum. The CT scans were reviewed with attention to the distribution of the lesions, appearance and attenuation of mediastinal lesions, enhancement pattern after intravenous contrast infusion and associated findings such as intercostal neurofibroma. In all five patients CT scans demonstrated fusiform low attenuated masses which were oriented longitudinally and extended over multiple contiguous scans along the distribution of major mediastinal nerves. In four patients, mediastinal lesions appeared infiltrative, obliterating adjacent mediastinal fat plane. One patient had well defined fusiform masses along the major mediastinal nerves. Postcontrast enhanced CT scans revealed slight central enhancement in two patient and no contrast enhancement in three patients. Associated findings such as neurofibromas of intercostal nerves and sympathetic trunk, or subcutaneous neurofibromas were detected on CT scans in all five patients. Characteristic CT findings of low attenuation masses along the major mediastinal nerves are helpful to differentiate plexiform neurofibromatosis from mediastinal lymphadenopathy and to prevent from misreading as a malignant disease

[en] To evaluate the clinical significance of the screening mammography in the detection of the breast diseases, especially breast carcinoma. We analyzed 1,800 cases of mammography retrospectively. The mammography was done as a part of routine check in Health Counselling Center, Korea University Medical Center, during 9 months from November 1993 to July 1994. The age range was from 23 years to 76 years, mean 49.8 years, and the largest age group was 6th decade (31.4%). According to the mammographic findings, we divided the subjects into three groups; normal group, abnormal group in need of follow-up study, abnormal group requiring biopsy. On mammography, the normal group consisted of 1,534 cases (85%), and the abnormal group consisted of 266 cases (15%). The abnormal findings were benign-looking calcification (n = 140), fibroadeno ma (n = 29), fibrocystic changes (n = 27), cyst (n = 23), malignant lesion (n = 15) lipoma (n = 7), and others. In four of 15 cases, which were suspected to be malignant on mammograms, breast carcinoma was confirmed pathologically. In four cases of breast carcinoma, one was under 40 and the other 3 were over 50 years of age. All of the breast cancers were under 3 cm in size, and the mammographic findings of breast cancer included spiculated margin (n = 3), parenchymal distortion (n = 3), malignant calcification (n = 2) and enlarged axillary node (n = 1). Screening mammogram is helpful for early detection of non-palpable breast cancer, especially for women over 50 years of age