Biomedical subjects
Publications and source records attributed to J A Verschakelen.
The case of a 75-year-old man with a history of hiatal hernia, who develops an acute gastric volvulus 17 days after a superior lobectomy of the left lung, is described. No similar cases were found in literature.
When fast, nondynamic scanning techniques are used in combination with adequate intravenous injection of contrast material, good-quality images of the pulmonary artery (PA) can be obtained with routine computed tomography (CT). The purpose of this study was to evaluate PA filling defects detected on these CT scans. Twenty-two CT scans from 22 patients with PA filling defects were reviewed. A routine scanning technique was used. Thrombus was unilateral in 12 cases and bilateral in 10. All patients but one had a predisposition for pulmonary embolism (PE). However, only five patients underwent CT because there was a strong suspicion for PE. In 17 cases, PE was not the first choice of clinical diagnosis; in 13 cases, thrombus of the PA was not even considered. Diagnosis was confirmed in 11 patients with ventilation-perfusion scanning (n = 7), angiography (n = 3), and surgery (n = 1). In 11 patients, anticoagulation therapy was started without further diagnostic procedures. Diagnosis of thrombus of the PA is possible with routine nondynamic, contrast material-enhanced CT. Because PE is often unsuspected at clinical examination, every contrast-enhanced CT scan of the chest should be evaluated for the presence of filling defects in the PA.
OBJECTIVE: Lung tissue, blood, and air determine the physical density of the lung and hence the attenuation measured on CT scans. These components are not homogeneously distributed throughout the lungs, and their relative proportion changes continuously during respiration. The objective of this study was to measure densities in various areas of the normal lung with CT and to examine the influences of gravity and of the degree of lung inflation on these densities. SUBJECTS AND METHODS: The subjects in the study were six healthy male volunteers. CT scans were obtained at the level of the aortic arch and 2 cm above the expiratory level of the diaphragm with the subjects supine and then with them prone. Scans were obtained at lung volumes of 10%, 50%, and 90% vital capacity by using a respiratory gating device connected to the CT scanner. The overall density of the lungs at these two levels and the densities in the dependent (posterior in supine, and anterior in prone body position) and nondependent (anterior in supine and posterior in prone body position) areas were measured by using a semiautomatic evaluation algorithm. RESULTS: Changes in lung volume caused the same changes in lung density in the right and left lungs and in the upper and lower parts of the lungs. For both body positions (supine and prone), the difference between lung density at 10% vital capacity and that at 90% vital capacity was significantly larger (p < .05) in the dependent parts of the lung than in the nondependent parts. In both positions, differences in density between dependent and nondependent regions were significantly (p < .05) greater at 10% vital capacity than at 90% vital capacity, and the differences became small when the volume of the lung was near total lung capacity. CONCLUSION: Changes in lung volume have different effects on changes in lung density in dependent and nondependent parts of the lung. The largest changes in lung density occur in the dependent regions. The difference in density between dependent and nondependent lung regions is smallest for lung volumes near total lung capacity. These findings may be useful as a baseline for interpreting CT measurements of regional lung density in suspected cases of lung disease, which would alter the physical density of lung tissue. Our results also suggest that measurements near total lung capacity should be included.
The clinical and radiological presentation of five anatomo-pathologically proven cases of localized pleural mesothelioma are described. In all patients conventional chest films and CT scans were performed. Two patients had also an MR examination. On conventional chest films all lesions presented as sharply defined homogeneous masses. In most cases there was inhomogeneous contrast enhancement on CT. In two cases calcifications and pleural effusion were present. There was no chest wall invasion, nor mediastinal adenopathy. On MR T1-weighted images, the tumor had an intermediate to high signal intensity. In the one case in which T2-weighted sequences were performed, tumor signal intensity increased compared to that on T1-weighted images. In contrast to what is generally found in literature and probably because the series contained rather large masses, most patients had symptoms while the mass was inhomogeneous on CT. Conventional chest films together with CT and MRI are helpful in differentiating this entity from malignant mesothelioma. However, focal areas of malignant degeneration cannot be excluded radiographically.
During semistatic inspiratory and expiratory vital capacity (VC) maneuvers, axial motion of the diaphragm was measured by lateral fluoroscopy and was compared with diaphragmatic volume displacement. Axial motion was measured at the anterior, middle, and posterior parts of the diaphragm, and the mean of these measurements was used. The volume displacement was calculated in two ways: first, from respiratory inductive plethysmograph-(Respitrace) derived cross-sectional area changes of rib cage and abdomen (Vdi,RIP) by means of a theoretical analysis described by Mead and Loring (J. Appl. Physiol. 53: 750-755, 1982) and, second, from fluoroscopically measured changes in position and anteroposterior surface of the diaphragm (Vdi,F). A very good linear relationship was found between Vdi,RIP and Vdi,F during inspiration as well as expiration (r greater than 0.95), indicating that the analysis of Mead and Loring was valid in the conditions of the present study. The diaphragmatic volume displacement (active or passive) accounted for 50-60% of VC. A very good linear relationship was also found between mean axial motion and volume displacement of the diaphragm measured with both methods during inspiration and expiration (r greater than 0.98). Our data suggest that, over the VC range, diaphragmatic displacement functionally can be represented by a pistonlike model, although topographically and anatomically it does not behave as a piston.
In recent years, much attention has been given to the role of CT in detecting and quantitating pulmonary emphysema. We measured CT lung density in 45 patients undergoing a diagnostic work-up and compared this with pulmonary function tests. The CT lung densities measured with the sector method and with the whole lung method were very highly correlated with each other (r = 0.96, p less than 0.001), and measurements at TLC systematically gave a lower density than those at FRC (p less than 0.001). Also, CT density measurements at TLC and even more so at FRC correlated well with pulmonary function indices of airway obstruction and of hyperinflation, but not with indices that are considered more specific for emphysema (single breath DCO, static lung compliance) We conclude that CT lung-density gives a good reflection of the degree of hyperinflation, ie, enlargement of distal airways, but is not sensitive to detect whether or not this is associated with emphysema.
To determine the importance of chest CT findings in patients with Swyer-James syndrome (unilateral small lung with air trapping) and to compare these findings with those on chest radiographs and scintigrams, we reviewed the CT scans, chest radiographs, and scintigrams of eight patients with the syndrome. Radiographs showed unilateral hyperlucency in seven patients and bilateral asymmetric hyperlucency in one. CT showed that the hyperlucency was unilateral in only three and that hyperlucency in one. CT showed that the hyperlucency was unilateral in only three and that hyperlucent regions on radiographs contained patches of normal lung attenuation in five patients. Conversely, in four patients, CT also showed small hyperlucencies in regions considered normal on radiographs. These lucencies usually had poorly defined margins and irregular shapes (five patients), but sometimes were peripheral, wedge shaped, and sharply demarcated (two patients). CT also showed subtle abnormalities not visible on radionuclide scans in two patients. Air trapping in hyperlucent regions was confirmed by a lack of change in volume on expiratory CT scans in five cases. Bronchiectasis was found in only three patients. CT helps to exclude central bronchial obstruction, cysts, and vascular disease as causes of hyperlucency. By excluding central obstruction, CT may make bronchoscopy unnecessary in some patients. CT is more sensitive than radiographs and radionuclide scans in detecting hyperlucent regions and in showing their distribution. Our experience suggests that bronchiectasis is not a necessary component of the Swyer-James syndrome.
A case of malignant pleural mesothelioma is presented. The initial pleural abnormalities were radiologically rather non-specific and were wrongly interpreted anatomo-pathologically as pleural metastases. Chemotherapy however resulted in an exceptional survival of more than 10 years. CT scan showed the extensive pleural damage. The histologic, symptomatologic and radiologic features of this rare tumor are discussed.
Right aortic arch is a rare congenital anomaly. It can be either an isolated finding or it can be part of a double aortic arch. This article discusses the radiographic appearance of this congenital anomaly on conventional chest X-ray, angiography, CT, and MRI.
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Computed tomographic (CT) scans of 24 bronchopulmonary sequestrations in 23 patients were reviewed. Seventeen sequestrations were diagnosed at surgery, three at angiography, and four on the basis of radiographic or CT findings combined with appropriate history. Sixteen sequestrations were intralobar, and eight were extralobar; 21 were posterobasal. Seventeen occurred on the left side and seven on the right. Anomalous systemic arterial supply was demonstrated by CT in 16 sequestrations. In the others, a systemic artery was not shown, presumably because of unfavorable orientation or small size of the vessel. The lung abnormalities shown by CT were classified into three types: A = cysts containing air or fluid (n = 8), or soft-tissue masses (n = 2); B = emphysematous lung surrounding cysts, and/or soft-tissue nodules (n = 13); and C = lung hypervascularity (n = 2). In only three cases did the chest radiograph show the emphysematous lung tissue. Such emphysematous lung has rarely before been reported as a CT finding, and lung hypervascularity has not, to the authors' knowledge, been reported. The authors conclude that CT can be helpful in the diagnosis and evaluation of bronchopulmonary sequestration. Characteristic manifestations are (a) a complex lesion containing solid or fluid components combined with emphysematous lung or (b) any basal lesion supplied by a systemic artery.
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Histiocytoma is an inflammatory pseudotumor usually found in the lung parenchyma or pleura. Endobronchial localisation is rare and can cause atelectasis or air-trapping. Conventional chest X-ray can show the tumor and secondary pulmonary changes. Conventional tomograms and CT can give additional information about tumor extension. However, to make the final diagnosis, biopsy is necessary.
The study of tumor extension and the diagnosis of invasion of the mediastinum are important features in the pre-operative staging of a lung tumor. MRI appears to be helpful. This paper gives a brief summary of the potentials and pitfalls of this technique.
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In eight healthy volunteers we simultaneously measured the axial diaphragmatic motion by fluoroscopy and the cross-sectional area changes of the rib cage (RC) and abdomen (ABD) by Respitrace (RIP) during semistatic vital capacities (VC). We found that, if the fluoroscopic axial displacement of the posterior part of the diaphragm between residual volume (RV) and total lung capacity (TLC) is considered equal to 100%, the movement of the middle part is 90%, whereas that of the anterior part is only approximately 60%; the ratio of the axial displacements to mouth volume, furthermore, decreases at high lung volumes, especially for the anterior part. The RIP signal is nearly linearly related to mouth volume, but the contribution of the RC (delta RC) progressively increases (and is approximately 80% RIP at TLC), whereas the volume contribution of the ABD (delta ABD) levels off (to 20% RIP at TLC). The diaphragmatic volume displacement calculated from the theoretical analysis described by Mead and Loring also levels off at high volumes similarly as the ABD but is approximately 50% RIP at TLC. Finally, the axial movements of the three parts of the diaphragm are linearly related to the RC and ABD cross-sectional-area changes (r 0.91-0.97) and are even significantly better correlated with the "calculated" diaphragmatic volume displacement.