Ultrasonic examination of pleural thickenings and calcifications in occupational asbestosis.

The roentgenologic diagnosis of occupational asbestosis is based upon typical pulmonary fibrosis and anteriorly detected pleural calcifications, which appear much later than parenchymal changes. Therefore, a definite diagnosis usually demands a long observation period. We used ultrasonic A-and B-mode methods to examine pleural changes in nine occupational asbestosis patients and five normal persons. In normal persons the parietal pleura was shown as a thin, sharp line when the B-mode method of examination was used. Roentgenographically observed calcifications were easily detected and distinguished from the normal pleura by this examination. It is noteworthy that similar echo peaks were seen in A-mode examinations in lateral and posterior pleura, where roentgenograms did not reveal pleural calcifications, and their size could be traced well with the B-mode examination. Thus it is possible to lind early pleural changes, which, in our opinion, are connected with occupational asbestosis. Diagnosis could be made earlier without a long observation time. p leural thickenings and calcifications can be caused either by pulmonary and pleural diseases or by hemothorax. In occupational asbestosis, pulmonary fibrosis and pleural calcifications are determined radiologically, but the latter have been studied very little. According to the literature, re-suits of investigations of the two are not similar. Jacob and Bohlig1 were the first to consider that pleural calcifications were sometimes caused by as-bestosis. Then in 1960, Kiviluoto2 created a new concept, that of nonoccupational endemic asbesto-sis, paying attention to the high incidence of cases with pleural calcification without an adequate history of pulmonary or pleural disease or injury. In addition in 1965, Kiviluoto3 found similar caleifica-tions in 77 patients. Hurwitz4 stated that calcified pleural plaques are typical in mild cases of asbesto-sis and that they are more frequent in asbestosis than roentgenologically discernible fibrotic changes of the lungs. Caravaglia5 found calcifications in 21.5 per cent of the occupational asbestosis patients he examined radiographically. Meurman#{176} stated that a discrepancy existed between the roentgenographic and autopsy findings of pleural calcifications in his study concerning asbestosis bodies and pleural plaques. Calcified plaques, especially those situated in the posterior parietal pleura, were seldom observed in roentgenograms. He also pointed out that dust and asbestos bodies do not seem to be the sole cause of plaque formation. In asbestosis patients, pleural calcifications are situated radiologically always toward the anterior section of the body and occur only after a long exposure to asbestos. However, the quality and quantity of pulmonary fibrosis differ …