Chest ultrasonography in health surveillance of asbestos related pleural disease

Background: the diagnosis of asbestos induced pleural involvement is based on the history of exposure, imaging, clinical and functional findings.CT is expensive, exposes to radiation and associates with increased psychological distress. Therefore, there is a growing need for simpler, low cost and safe medical testing for early detection of pleural abnormalities in asbestos exposed workers.We tested pleural ultrasonography in subjects with an occupational exposure to asbestos and compared its diagnostic accuracy with that of HRCT.Materials and Methods: we enrolled subjects with documented occupational exposure to crysothile asbestos. To the conventional screening including chest HRCT and lung function tests, systematic ultrasound evaluation of the pleural space was added. Results were compared with those of HRCT.Results: 107 out of 141 screened subjects were recruited. Pleural abnormalities at US and/or HRCT were detected in 61 (prevalence of 57%). CT identifed 18 subjects with pleural abnormalities. US recognized 12/18 subjects described by CT and further visualized 43 participants whose lesions were not seen at the CT. Of those with proven pleural abnormalities, only 6 were not recognized by US (9.8%). Overall, positive percent agreement and negative percent agreement were 54%, 66.6% and 51.8%, respectively; the McNemar’s test showed a p value <0.001. USs revealed smaller abnormalities than CT, with a mean size of the lesions of 4.8 (±7.6) millimeters vs 6.6 (±7.4), respectively (p=ns).Conclusions: US can detect pleural changes under the 10 millimeters minimally measurable lesion thickness threshold on CT and may integrate it for an earlier and easier diagnosis in high risk patients.