Swyer-James syndrome: CT findings in eight patients.

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.

Legionnaires' disease.

The Legionella bacillus is a relatively common pulmonary pathogen that has been responsible for a number of outbreaks of respiratory illness this century. Not until 1976, however, after exciting epidemiologic and microbiologic investigation, was the organism isolated and identified. Legionnaires' disease does not have a characteristic radiographic appearance, but certain features may alert the clinician to its presence. It often rapidly progresses to a lobar pneumonia that may not respond immediately to treatment. The radiographic findings lag behind clinical improvement, and radiographic resolution is prolonged. Organ transplantation patients often present with ill-defined, rounded, pleura-based opacities that may simulate pulmonary infarction and can cavitate.

Pleural and mediastinal changes following endoscopic injection sclerotherapy of esophageal varices.

Postero-anterior and lateral chest radiographs of patients undergoing endoscopic injection sclerotherapy of esophageal varices were reviewed. Radiographs were obtained prior to and within 48 hours of treatment. Following sclerotherapy, pleural effusions and densities were commonly seen at the azygoesophageal reflection and the posterior wall of the bronchus intermedius; however, on follow-up they had resolved. Most patients were asymptomatic, and morbidity was low. These findings suggest that inflammation developing after endoscopic injection sclerotherapy extends beyond the esophageal wall into the mediastinum and pleural space.

The chest radiograph in Legionnaires' disease. Further observations.

Chest radiographs of 70 patients with Legionnaires' disease were evaluated and compared to the authors' previous series of 24 patients as well as others in the literature. A larger number of patients in the more recent survey had pleural effusion, and there were 3 with cavitation whereas none was seen previously. Analysis of the radiograph showing the most marked changes in survivors versus patients who died showed no consistent pattern, indicating that the radiograph cannot be used as a prognostic indicator. On long-term follow-up (mean, 104.2 days), the radiograph remained abnormal for many months and demonstrated a variety of slowly resolving or permanent abnormalities.

Knowledge-based computer-assisted diagnosis of chest radiographs.

The computer can produce structured radiologic content which can potentially keep the radiologists current in radiology literature. As the radiologist continues to make observations and uses the available information, he has at his fingertips with the computer the current information to offer appropriate differential diagnosis and suggest appropriate patient follow up. The computer allows the radiologist to learn and grow rather than guess and hope.

The chest radiograph in legionnaires' disease.

The chest radiographs of 24 patients with documented Legionnaires' disease were evaluated. Twenty-two of the 24 patients had positive findings for the disease initially. There was unilateral involvement in 68% and the most common lung shadows were poorly marginated round opacities (46%), diffuse patchy (25%) and peripheral opacities (21%). At peak, 70% of patients had a lobar shadow. Pleural effusions were present in 39% of cases but could be explained by underlying congestive heart failure or renal failure in 7 of the 9. Although the findings are not specific, the radiologist should consider this diagnosis in a patient with compatible clinical history, a pneumonia of obscure etiology, and these radiographic manifestations.