Biomedical subjects
Publications and source records attributed to E J Stern.
Although the pleural cavities are anatomically separate in humans, we describe bilateral pneumothoraces that occurred after percutaneous needle biopsy of the lung. In some individuals, there may be communication between the pleural spaces; it is important for those performing interventional procedures to be aware of this uncommon anatomic variant.
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OBJECTIVE: We reviewed the imaging findings in nine patients with idiopathic giant bullous emphysema. This progressive condition is characterized by large bullae, usually seen in association with several forms of emphysema, and usually occurs in young men, most of whom are smokers. MATERIALS AND METHODS: Nine patients with chest radiographic evidence of a bulla or bullae occupying at least one third of a hemithorax, who had also been examined with high-resolution CT, were included in this retrospective study. We examined the size, distribution, and locations of bullae. On high-resolution CT scans, bullae were categorized as predominantly subpleural or intraparenchymal. RESULTS: In eight of the nine cases, the chest radiographs showed variable asymmetry in the distribution of bullae. Bullous disease involved predominantly the upper lobes. High-resolution CT showed bullae from 1 to 20 cm in diameter, but most were 2-8 cm in diameter. Paraseptal emphysema and subpleural bullae were the predominant findings in all nine patients. Seven patients had separate centrilobular emphysema of various degrees and intraparenchymal bullae. None of the intraparenchymal bullae were larger than 2-3 cm. Additionally, two non-small-cell lung cancers were seen in our series. CONCLUSION: The dominant and consistent feature seen on high-resolution CT scans in both smokers and nonsmokers is extensive paraseptal emphysema merging into giant bullae. Associated centrilobular emphysema, seen in cigarette smokers, is the important variable finding for determining the extent of underlying parenchymal disease, which may help in the preoperative assessment of giant bullous lung disease.
OBJECTIVE: Recent reports have described severe precocious pulmonary emphysema in persons who inject methylphenidate (crushed Ritalin tablets) i.v. We retrospectively evaluated the plain radiographic and CT features in 21 such patients. MATERIALS AND METHODS: The chest radiographs, available CT scans, and clinical and pathologic data were reviewed in 21 cases of i.v. Ritalin use. The patients were from 35 to 54 years old. Twelve patients were men, and nine were women. Emphysema was graded on the basis of findings on chest radiographs, by consensus, on a four-point scale as absent, mild, moderate, or severe. CT scans were available for three patients, including one imaged after a single lung transplantation. Autopsy results were available for four patients. Fixed inflated lung specimens and corresponding high-resolution CT scans were available in three cases. RESULTS: Radiographs showed pulmonary emphysema in all cases. The distribution of disease was basilar and symmetric. Small apical bullae were suggested in only one case. Basilar emphysema was rated as mild in four patients, moderate in three patients, and severe in 14 patients. In 11 patients who had serial chest radiographs, the basilar emphysema was noted to progress over a 2- to 7-year period. No evidence of progressive massive fibrosis was seen in any patient. CT scans confirmed emphysema, most severe at the lung bases. CONCLUSION: The plain radiographic and CT findings in patients who inject Ritalin are similar to those found in patients with alpha 1-antitrypsin deficiency and different from the findings seen in other types of i.v. drug use. The finding of basilar pulmonary emphysema should alert the radiologist to the possibility of i.v. injection of Ritalin.
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We investigated a method for increasing the utility of a radiology information system by connecting it to a personal-computer network and transferring radiologic data to a more user-friendly, familiar computing environment. We have developed a personal-computer local-area network that is linked to our radiology information system. Our software periodically transfers data from the radiology information system to a file server on our network that supports cross-platform access for Macintosh and IBM PC--compatible computers. Data are stored in formats compatible with inexpensive personal-computer software. These capabilities facilitate any research that requires a tailored, retrospective analysis of radiologic data. The need for ancillary personnel to perform paper-based searches or redundant data entry is decreased. Radiologists and administrators also have user-friendly access to information that might facilitate other projects dealing with education or analysis of clinical efficacy. The ever-growing power of personal computers, combined with inexpensive yet sophisticated software for these machines, frequently provides a more useful method for retrospective analysis of radiologic data than does a proprietary radiology information system running on a minicomputer.
Pulmonary emphysema is a pathologic diagnosis. However, the diagnosis can be made with relative certainty on the basis of clinical and radiologic criteria. The clinical diagnosis of emphysema can be difficult because correlations between results of lung function tests and the extent of emphysema are poor. Additionally, features of other obstructive lung diseases may overlap. From the clinician's standpoint, the main value of differentiating between emphysema and other obstructive diseases of the airways (e.g., asthma and chronic bronchitis) is to (1) establish a prognosis and (2) guide the use of corticosteroid therapy by defining the degree of reversibility that can be expected in patients with limitation in air flow.
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CT performed in patients during suspended full expiration has recently been used to reveal a major physiologic consequence of airway diseases, particularly diseases of those smaller airways beyond the segmental branches: air trapping. Lung regions that retain air during exhalation (air trapping) remain more lucent than normal lung regions do. Detection of air trapping can provide clues to an otherwise unsuspected or underappreciated small-airway disease.
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Improvements in scan speed and resolution are changing the role of the pulmonary imager. An understanding of airway mechanics and blood flow physiology is required to take full advantage of the new technology. Assessment of regional airflow and blood flow provides information that is currently unavailable from clinical tools.
RATIONALE AND OBJECTIVES: Nine patients were examined using dynamic electron beam computed tomography to assess the utility of this technique in detecting airway obstruction and air trapping, and to compare this technique with pulmonary physiologic testing. METHODS: Dynamic computed tomography (C-100 Ultrafast CT scanner, Imatron, Inc., South San Francisco, CA) was performed, with a series of ten, 100-msec images obtained in a 6-second period during forced inhalation and exhalation. Time-attenuation curves were calculated from the observed changes in lung attenuation. Estimates of the percentage of each lung that showed air trapping were made at each level scanned, using a 5-point scale. Specific correlations were made for pulmonary function test results and air-trapping score. RESULTS: In all nine patients, dynamic computed tomography demonstrated one or more sites that failed to show a normal increase in lung attenuation during forced exhalation. Four of these 9 patients showed a paradoxical decrease in lung attenuation during exhalation in at least one region of the lung. Extent of air-trapping correlated well with forced expiratory volume in one second (r = -.92). CONCLUSIONS: Based on this small sample, the authors believe that this technique will prove sensitive for detecting abnormalities of ventilation and may be a useful adjunct to conventional diagnostic procedures in the management of disorders of airway obstruction.
To aid in the diagnosis of lung diseases associated with airway obstruction and air-trapping, we use dynamic ultrafast high-resolution computed tomography (DUHRCT). We obtain a rapid series of ultrafast HRCT scans during a forced inspiratory and expiratory maneuver to demonstrate dynamic lung attenuation changes. Alteration in lung morphology can be seen coincident with changes in lung attenuation during different phases of the respiratory cycle. Lung attenuation changes can be evaluated qualitatively or quantitatively by using time-attenuation curves measured for specific regions of lung. In a normal population, we noted that the lingula is a common site of unsuspected and asymptomatic air-trapping. In subjects with airway obstruction, and in those with cystic lung disease, air-trapping is readily detected, even at the secondary pulmonary lobule level. In some of those cases with air-trapping, a paradoxical decrease in lung attenuation was noted during forced exhalation. Recent development of spiral CT scanners may allow more common usage of a similar dynamic technique. Simple paired inspiratory and expiratory scans, obtained during suspended respiration at the same level, may be sufficient for the detection of air-trapping in many patients.
The authors examined 10 healthy male subjects with dynamic computed tomography to determine normal dynamic and expiratory findings. In both the supine and prone positions, the average increase in lung attenuation during exhalation was found to be significantly greater in dependent lung regions than in nondependent lung regions. In each of the lung zones studied, there was a significant correlation between the decrease in cross-sectional lung area during exhalation and the increase in lung attenuation. At the lung bases, a greater increase in lung attenuation was noted during exhalation for a given change in cross-sectional lung area than in the upper lungs. All 10 subjects showed a distinct lobar attenuation gradient in the supine position. In general, lung attenuation increased homogeneously during exhalation, but four of the 10 subjects showed regions of inhomogeneity in lung attenuation during rapid exhalation indicative of air trapping, despite normal results on pulmonary function tests.
The purpose of this study was to define the range of normal intrathoracic tracheal diameters and cross-sectional areas during forced respiration. A report of tracheomalacia is also presented. Ten volunteers were studied in the supine position with dynamic computed tomography (CT), at a level at or between the brachiocephalic vein and the aortic arch, with 3-mm collimation and with image reconstruction by means of a high-spatial-frequency algorithm. Ten 100-msec dynamic scans were obtained at 500-msec intervals during a 6-second period as the patient performed forced inspiration and expiration vital capacity maneuvers. The mean cross-sectional area of the trachea decreased dynamically from 280 mm2 at end inspiration (standard deviation, 50.5; range, 221-388 mm2) to 178 mm2 at end expiration (standard deviation, 40.2; range, 115-236 mm2; P < .001) (mean decrease, 35% between inspiration and expiration; standard deviation, 18%; range, 11%-61%). The percentage decrease in cross-sectional area of the trachea correlates well with the decrease in the anteroposterior and coronal diameters of the trachea from maximum inspiration to maximum expiration (r = .879 and .916 and P = .0018 and .0002, respectively).
The authors used a gantry tilt of 20 degrees in five patients to allow fine-needle aspiration biopsy of peripheral pulmonary lesions that were difficult to approach with a vertical alignment because of overlying ribs. This method allowed a direct approach to the lesion in all five cases, with the entire needle path visible in the scanning plane, avoidance of vital structures, and traversal of a minimal amount of normal lung parenchyma.
Pneumocystis carinii pneumonia (PCP) remains the most common lethal opportunistic pulmonary infection in patients infected with the human immunodeficiency virus (HIV). Although the use of prophylactic inhaled pentamidine has effectively reduced the frequency of primary and recurrent episodes of PCP, the aerosolization of pentamidine may have altered the localization of active PCP, resulting in more upper lobe disease. The distribution of disease may have also affected the diagnostic accuracy of standard bronchoalveolar lavage of the middle lobe, with a reduction in sensitivity from about 90 to 65%. In retrospective surveys of patients from our institution, Steiger and Fahy found that pooled multiple-lobe radiographic site-directed bronchoalveolar lavage resulted in diagnostic sensitivities of 91 and 100%, respectively. We performed a follow-up prospective study of 38 consecutive patients on aerosolized pentamidine in whom we lavaged both the middle lobe and an upper lobe. We found that bilobar lavage including routine lavage of an upper lobe increases the diagnostic sensitivity of bronchoalveolar lavage alone to 95% compared with 65% if lavage is performed only in the middle lobe (p < 0.05). Radiographic studies demonstrate a concordant increase in exclusive or predominant upper lobe disease in patients on aerosolized pentamidine, but our results indicate that PCP is recovered more frequently from the upper lobe regardless of the radiographic appearance. We conclude that all patients on prophylactic inhaled pentamidine should undergo bilobar lavage with the inclusion of an upper lobe in the initial evaluation of possible PCP. The diagnostic sensitivity of 95% makes bilobar bronchoalveolar lavage an acceptable sole initial diagnostic modality without the need for initial transbronchial lung biopsy.