Conventional Chest Films Can Reveal Emphysema, BUT NOT COPD

REFERENCES 1 Crystal RG, Fulmer JD, Roberts WC, Moss ML, Line BR, Reynolds HY. Idiopathic pulmonary fibrosis: clinical, histologic, radiographic, physiologic, scintigraphic, cytologic, and biochemical aspects. Ann Intern Med 1976; 85:769-88 2 Crystal RG, Gadek JE, Ferrans VJ, Fulmer JD, Line BR, Hunninghake GW Interstitial lung diseases: current concepts of pathogenesis, staging, and therapy. Am J Med 1981; 70:542-68 3 Crystal RG, Bittennan PB, Rennard SI, Hance AJ, Keogh B. Interstitial lung disease of unknown cause: disorders characterized by inflammation of the lower respiratory tract. N Eng! J Med. 1984; 310:154-166, 235, 244 4 Libby OM, Gibofsky A, Fotino M, Waters SJ, Smith JP. Immunogenetic and clinical findings in idiopathic pulmonary fibrosis: increased incidence of HLA-Dr2. Am Rev Respir Dis 1983; 127:618-22 5 Davis WB, Fells GA, Sun X-H. Gadek JE, VenetA, Crystal RG. Eosinophil-medicated injury to lung parenchymal cells and interstitial matrix: a possible role for eosinophils in chronic inflammatory disorders of the lower respiratory tract. JClin Invest 1984; 74:269-78 6 Rudd RM , Haslam PL, Turner-Warwick M. Cryptogenic fibrosing alveolitis: relationships of pulmonary physiology and bronchoalveolar lavage to response to treatment and prognosis. Am Rev Respir Dis 1981; 124:1-8 7 Dechatelet LR, Migler RA, Shirley RS, Bass DA, McCall CE. Enzymes of oxidative metabolism in the human eosinophil. Proc Soc Exp Bioi Med 1978; 158:537-41 8 Libby OM, MurphyTF, Edwards A, Gray G, KingTKC. Chronic eosinophilic pneumonia-an unusual cause of acute respiratory failure. Am Rev Respir Dis 1980; 122:487-500

Conventional Chest Films Can Reveal Emphysema, BUTNOTCOPD

_k article appearing in the Review section of (this

month's) American journal ofMedicine should be of interest to many readers of Chest. It deals with the value of conventional chest radiography both for the diagnosis and for exclusion of the diagnosis of emphysema. Most chest physicians are aware that this has been a subject of controversy and conflicting reports for many years. The article reviews each of the relevant articles and explains how differences in the criteria used by, and in the intentions of, the various authors have led to diametrically opposite conclusions. The point is made that technical procedures are so different that poor results in one study should not be construed as reducing the validity of successful interpretations in any other study. While not wishing to repeat here the evidence and reasoning presented in the review article, 1 one of the key points does merit reemphasis. This point concerns the role of the currently accepted definition of emphysema which is based on its effects on lung structure. In considering the value of radiography in emphysema, it is necessary to adhere strictly to this definition. Several autopsy studies have shown that emphysema

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can be present and can involve as much as 25 or 30 percent of the lung in asymptomatic patients, many of whom can even have normal forced expiratory flow rates. 2-4 Autopsy studies have also shown that some patients who do have symptoms of respiratory impairment and do have reduced expiratory flow rates (and may even have died from respiratory failure), do not have any emphysematous lung destruction. ~7 Chest films, of course, reflect lung structure, not function, and diagnostic criteria must necessarily be validated by correlation with autopsy findings. When validated criteria are present in films of a nonimpaired individual, the radiographic diagnosis of emphysema should be viewed as a "true positive" not a "false positive;" and, when they are absent in a patient with impairment, the result is a "true negative," not "false negative." In furtherance of this concept, radiologists and others who interpret chest films should be especially careful to avoid use of the term "obstructive lung disease." They should use instead the term "emphysema" and determine whether a patient's films meet or do not meet the criteria for that diagnosis. Clinical observation or physiologic testing will reveal the presence or absence of obstructive impairment. The radiologic information will be useful in either clinical situation. For further details, readers should examine the review article. 1 Philip C. Pratt, M .D ., F.C .C.P. Durham Professor of Pathology, Duke University Medical Center.

REFERENCES 1 Pratt PC. The role of conventional chest radiography in diagnosis and exclusion of emphysema. Am J Med 1987; 82:998-1006 2 Sweet HC, Wyatt JP, Fritsch A, Kinsella PW Panlobular and centrilobular emphysema: Correlations of clinical findings with pathologic patterns. Ann Intern Med 1961; 55:565-81 3 Pratt PC, Jutabha 0, Klugh GA. Quantitative relationship between structural extent of centrilobular emphysema and postmortem volume and flow characteristics oflungs. Med Thor 1965; 22:197-207 4 Thurlbeck WM, Henderson JA, Fraser RG, Bates DV. Chronic obstructive lung disease: a comparison between clinical, roentgenographic, functional, and morphologic criteria in chronic bronchitis, emphysema, asthma, and bronchiectasis. Medicine 1970; 49:82-145 5 Mitchell RS, Ryan SF, Petty TL, Filley GF. The significance of morphologic hyperplastic bronchitis. Am Rev Respir Dis 1966; 93:720-29 6 Karpick RJ, Pratt PC, Asmundsson T, Kilburn KH. Pathologic findings in respiratory failure: goblet cell metaplasia, alveolar damage, and myocardial infarction. Ann Intern Med 1970; 72:189-97 7 Gamsu G, Nadel ]A. The roentgenologic manifestations of emphysema and chronic bronchitis. Med Clin North Am 1973; 57:719-33

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