Roentgenographic evidence for predominant left-sided location of unilateral pleural plaques.

The roentgenographic prevalence and anatomic distribution of pleural plaques were studied in the US Navy Asbestos Medical Surveillance Program population (105,064 individuals as of July 17, 1985). "Definite" or "probable" pleural plaques were noted in 4.4 percent of films. These were unilateral in 19.3 percent of roentgenograms with "definite" pleural plaque and 33.9 percent of films with "probable" pleural plaque. Unilateral findings were more often left-sided than right-sided; a ratio of 287:82 in the "definite" group and 625:287 in the "probable" group. Left-sided predominance of unilateral plaque is a consistent and unexplained epidemiologic finding that may provide clues to pleural pathogenesis following asbestos exposure.