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Biomedical subjects

J G Im

Publications and source records attributed to J G Im.

At least 91 records · Page 5Linked to original sources
PubMed1991

Imaging of the pleura.

With the use of plain radiography, CT, sonography, and more recently MR imaging, radiology has played a pivotal role in the diagnosis and treatment of patients with pleural effusions. The expanding use of CT scanning in patients with pleural disease has enhanced not only our understanding of the factors that affect the distribution of pleural fluid within the thorax, but also our understanding of pathologic and pathophysiologic changes in patients with pleural disease. This paper reviews significant recent developments in this area.

Diagnostic Imaging↗
PubMed1990

Lobar bronchioloalveolar carcinoma: "angiogram sign" on CT scans.

The authors reviewed computed tomographic (CT) scans of 12 patients with lobar bronchioloalveolar carcinoma. Seven patients had consolidation of the entire lobe, and five patients had segmental consolidation. After contrast material was administered intravenously, the consolidated lung typically appeared on the scan as an area of homogeneous low attenuation, within which were enhanced branching pulmonary vessels (the CT angiogram sign). To evaluate the specificity of this sign in the discrimination of bronchioloalveolar carcinoma, CT scans of 26 patients who had lobar consolidation from other diseases were randomly mixed with the CT scans of 11 patients with bronchioloalveolar carcinoma. Two independent observers who were unfamiliar with the cases classified 10 and nine of the 11 patients with bronchioloalveolar carcinoma, respectively, as positive for bronchioloalveolar carcinoma by applying the CT angiogram sign, and classified as negative 25 and 23 of the 26 patients without bronchioloalveolar carcinoma, respectively, for an overall specificity of 92.3%. The angiogram sign appeared on the CT scan because of the low-attenuating consolidation, which was caused by the production of mucin or other fluid and the intact bronchovascular framework within the tumor.

Adenocarcinoma, Bronchiolo-Alveolar↗
PubMed1990

Mitral stenosis: evaluation with MR imaging after percutaneous balloon valvuloplasty.

To evaluate the pathoanatomic findings of mitral valve stenosis and changes after percutaneous balloon valvuloplasty (PBV), magnetic resonance (MR) imaging was performed in 23 patients. The patients were imaged with a 2.0-T system within 1 week before and 3-10 days after PBV. The angle of the interatrial septum was measured on the transverse image to facilitate a successful transseptal puncture. On MR images, the mean transverse and anteroposterior diameters of the left atrium at the level of the aortic root in the ventricular diastolic phase decreased significantly after PBV. Areas of flow-related intraluminal signal intensity detected in the left atrial cavity of 17 patients (74%) before the procedure disappeared in 15 patients after the procedure. Other MR imaging findings after PBV were the disappearance of intraluminal signal intensity in the pulmonary artery, normal curvature of the interatrial and interventricular septa, and pericardial effusion as a complication. MR imaging was thought to provide useful information before and after PBV in patients with mitral stenosis.

Adolescent↗
PubMed1989

Hepatosplenic tuberculosis with hypersplenism: CT evaluation.

Hepatosplenic tuberculosis of macronodular form is extremely rare. We present one case of hepatosplenic tuberculosis with its appearance on computed tomography (CT). The CT findings of hepatosplenic tuberculosis were multiple, well-defined, round or ovoid, low-density masses with a range of +35 to +45 HU. Lymphadenopathy in the abdominal and mediastinal area and pleural effusion were also found. Although CT does not confirm a diagnosis of hepatosplenic tuberculosis, it is a valuable examination to support the diagnosis and define the extent of disease.

Female↗
PubMed1989

Costal pleura: appearances at high-resolution CT.

The appearance of the costal pleura at high-resolution computed tomography (CT) was evaluated with a cadaver and 25 normal subjects. This was contrasted with the high-resolution CT appearance of the costal pleura in 15 patients with mild pleural thickening, 13 of whom had been exposed to asbestos. On high-resolution CT scans in the normal subjects, a 1-2-mm-thick line of soft-tissue attenuation at the point of contact between lung and chest wall represents the visceral and parietal pleura, pleural contents, endothoracic fascia, and innermost intercostal muscle. In a paravertebral location, the innermost intercostal muscle is lacking, and a thin line seen on high-resolution CT scans reflects pleura and endothoracic fascia. Transverse thoracic and subcostal muscles and extrapleural fat pads can be seen as tissue internal to a rib and may be confused with pleural thickening. In 13 of the 15 patients with mild pleural thickening, the 1-3-mm-thick pleura was separable from the underlying normal intercostal muscle by a layer of extrapleural fat. High-resolution CT was more sensitive than CT with 1-cm collimation in depicting this degree of pleural abnormality.

Aged↗
PubMed1989

Leptospirosis of the lung: radiographic findings in 58 patients.

Leptospirosis is the disease produced by any of the group of spirochetes of the genus Leptospira. The main organs involved are the liver, central nervous system, kidneys, skeletal muscle, and lungs. Thirty-seven (64%) of 58 patients with leptospirosis, proved by positive serology, had pulmonary radiographic findings. Three radiographic patterns were evident: (1) 21 (57%) of the 37 patients had small nodular densities, (2) six (16%) had large confluent areas of consolidation, and (3) 10 (27%) had diffuse, ill-defined, ground-glass density. Serial radiographs showed a tendency for the nodular pattern to be followed by confluent consolidation and/or ground-glass density. Abnormalities were bilateral, nonlobar in all cases, and had a marked tendency toward peripheral predominance. Pulmonary abnormalities resolved within 15 days, except in eight patients who died because of respiratory failure (six patients) or other causes (two patients). In order to correlate pathology with the radiographic findings, Leptospira, isolated from a patient, was injected intraperitoneally into 20 guinea pigs. All lungs from the guinea pigs showed petecheal hemorrhage, which progressed to large confluent areas of hemorrhage. The typical pulmonary radiographic findings of leptospirosis are compatible with the multifocal pulmonary hemorrhage seen in the guinea pigs.

Adult↗
PubMed1988

Exogastric cystic gastric leiomyoblastoma with unusual CT appearance.

Gastric leiomyoblastomas are rare tumors between leiomyomas and leiomyosarcomas in terms of their malignant potential. This article describes 2 cases of exogastric cystic gastric leiomyoblastoma with unusual location and computed tomographic (CT) appearance. The CT findings of these cases were unlike those of usual smooth muscle tumors, but closely simulated cystadenomatous tumor of the ovary or pancreas.

Aged↗
PubMed1988

Normal and diseased isolated lungs: high-resolution CT.

High-resolution computed tomography (CT) scans of 12 isolated, inflated, fresh lungs obtained at autopsy were compared with thin, paper-mounted lung sections obtained at the same levels. In six lungs considered intrinsically normal, high-resolution CT showed normal interlobular septa and pulmonary arteries in the lobular core, but lobular bronchioles were not visible. Edematous fluid resulted in thickening and increased visibility of interlobular septa. In three emphysematous lungs, high-resolution CT accurately demonstrated the degree of emphysema and suggested its centrilobular nature. In two lungs with honeycombing, cysts lined by fibrosis were easily seen on high-resolution CT scans. In less severely involved areas, septal thickening and intralobular fibrosis were seen on high-resolution CT scans, but small (1 mm) cysts were invisible. High-resolution CT was able to demonstrate some features of the normal secondary pulmonary lobule and structural alterations produced by various diseases.

Humans↗
PubMed1988

CT densitometry of pulmonary nodules in a frozen human thorax.

The influence of (1) calcium concentration, (2) exposure technique, (3) reconstruction algorithm, (4) nodule size, and (5) nodule location on the CT attenuation values (CT density) of pulmonary nodules was examined in a frozen human thorax. Nodules with calcium concentrations of 0-310 mg/ml and diameters of either 0.95 or 1.59 cm were inserted into a frozen, unembalmed human thorax. The nodules were placed either at the lung apex or 4 cm below the tracheal carina. Each nodule was scanned on a GE CT 9800 scanner; five different exposure techniques were used. The slice thickness was uniformly 1.5 mm. As expected, increasing the kilovoltage caused a significant decrease in CT nodule density in all nodules with calcium concentrations greater than 80 mg/ml. The inverse relationship between kilovoltage and nodule density was exaggerated with increasing calcium concentration. A high-resolution (bone) algorithm gave a significantly higher CT number than did a smoothed (standard) algorithm, regardless of nodule size and location, but this difference could be attributed almost entirely to the edge-enhancement effect of the bone algorithm. The CT density of the larger nodules was significantly higher than that of the smaller nodules at calcium concentrations greater than 65 mg/ml for both standard and bone algorithms. Densities were significantly higher in the mid lung than in the apex with a standard algorithm, but this was not the case with a bone algorithm. The GE CT 9800 scanner had a linear response between CT density and increasing calcium concentration within the confines of a human thorax. A high-resolution (bone) reconstruction algorithm has higher spatial resolution but does show an edge-enhancing effect not found with the smoothed algorithm. Two major variables in CT densitometry for pulmonary nodules are the kilo electron voltage of the X-ray beam and the reconstruction algorithm used; these two parameters should be standardized, with a high kilovoltage and high-resolution algorithm favored on the GE CT 9800 scanner.

Absorptiometry, Photon↗
PubMed1988

MR imaging of the transverse sinus of the pericardium.

On MR images of the chest, a low-signal-intensity band is often seen between the ascending aorta and left atrium in the transverse plane, and between the right pulmonary artery and left atrium in the coronal and sagittal planes. CT and MR of cadavers, with injection of contrast media into the pericardial space, confirmed that this structure was the transverse sinus of the pericardium. Retrospective review of MR studies in 45 patients without evidence of pericardial disease showed the transverse sinus of the pericardium in 80% (32/40) of transverse ECG-gated images, 78% (7/9) of sagittal ECG-gated images, and 67% (14/21) of coronal ECG-gated images. Nongated studies showed the sinus infrequently. Knowledge of the three-dimensional anatomy of the transverse sinus of the pericardium and of its typical MR appearance should allow its recognition and preclude misinterpretation.

Adolescent↗
PubMed1987

Mediastinal tuberculous lymphadenitis: CT manifestations.

An analysis was done of computed tomographic (CT) scans of 23 Korean patients who had presented with a mediastinal or hilar mass on plain chest radiographs and had subsequently been found to have tuberculous lymphadenitis. Most patients were young adults. Findings of pulmonary tuberculosis were seen on plain radiographs in 14 patients. On CT, findings were of an overwhelming preponderance of involvement of the right paratracheal and tracheobronchial nodes. After injection of contrast medium, nodes larger than 2 cm in diameter invariably showed central areas of relative low density and peripheral rim enhancement. Enhanced walls were usually irregular in thickness. Some smaller nodes did not show low-density areas, but instead showed varying degrees of homogeneous enhancement. Although metastatic nodes can be of low density, experience in this study suggests that mediastinal lymphadenopathy in a young adult with the CT findings described above is characteristic enough to support a diagnosis of tuberculosis.

Adolescent↗
PubMed1987

The inferior accessory hepatic fissure: sonographic appearance.

The inferior accessory hepatic fissure, a coronal or parasagittal fissure through the parenchyma of the posterior segment of the right hepatic lobe, was observed sonographically in 15 of 2000 patients. The fissure was seen as a thin, echogenic membrane stretching downward from the right branch of the portal vein to the inferior surface of the right hepatic lobe. On cadaveric sections, the fissure was an invagination of peritoneum directed laterally and slightly posteriorly from the medial inferior surface of the right hepatic lobe below the porta hepatis.

Humans↗
PubMed1986

Transcatheter renal arterial embolization with the mixture of ethanol and iodized oil (Lipiodol).

We induced experimental renal arterial embolization with the radiopaque solution of ethanol and iodized oil (Lipiodol) in 35 rabbits to evaluate the capability of the mixture to induce renal ablation. Serial renal angiography and plain abdominal radiography were performed immediately, one week and two weeks after embolization. Neither pure Lipiodol nor a 50% ethanol solution caused renal embolization. However, infusion of 50% and 75% ethanol-Lipiodol solutions resulted in embolization equal to that caused by absolute ethanol. The 50% ethanol-Lipiodol solution was so radiopaque that we could easily observe the embolization process during fluoroscopy. Renal arterial embolization with the 50% ethanol-Lipiodol solution was successful in three patients with hypernephroma. Our results suggest that a 50% ethanol-Lipiodol solution is radiopaque and an effective agent for renal arterial embolization.

Animals↗
PubMedDate not supplied

Castleman disease with renal amyloidosis: imaging findings and clinical significance.

We report two cases of renal amyloidosis associated with mesenteric and mediastinal Castleman disease of plasma cell type. Computed tomographic (CT) scan revealed a mesenteric mass with multiple nodal enlargement in one patient and a right paratracheal mass with irregular central calcifications in the second patient. Renal ultrasonography (US) showed increased echogenicity of the renal parenchyma with prominent medullas. Doppler waveform obtained in the kidney associated with mesenteric disease showed complete absence of diastolic flow signal, although it was normal in the patient with mediastinal disease. Recognition of Castleman disease as the cause of renal amyloidosis and the understanding of CT and US findings of this entity are important for the management, as well as its diagnosis.

Adult↗
PubMedDate not supplied

Magnetic resonance evaluation of mitral stenosis.

In order to study magnetic resonance (MR) abnormalities in mitral stenosis, electrocardiogram (ECG)-gated MR imaging was performed with a 2.0 T MR system in 41 patients with mitral stenosis before catheterization. Mean transverse diameter of the left atrium was 8.9 +/- 1.4 cm and anteroposterior diameter was 5.1 +/- 1.0 cm, indicating significant enlargement. Homogeneous or inhomogeneous flow-related signals in ventricular diastole were detected in the left atrial cavity in 32 cases (78%), and in the atrial appendage in 35 cases (85%). In 21 patients having a mean wedge pulmonary arterial pressure higher than 20 mm Hg, 20 patients (95%) showed flow-related signals in ventricular diastole. Other MR findings were mitral valve doming in diastole, flow-related signal in the pulmonary artery during systole, and left atrial thrombi.

Adolescent↗