False-Positive Asbestosis Reports

Development of asbestosis results from exposure to asbestos, a harmful mineral mined, manufactured, and consumed in the United States in large quantities until 1979. The interpretation of chest radiographs in patients with suspected asbestosis is often extremely difficult. A recent study by the UCLA Medical Center identified 27 patients with a history of asbestos exposure that were referred to them by the United State Department of Labor. All patients were told that they had asbestosis based on their asbestos exposure history and abnormal chest radiographs. Interestingly, after review by UCLA doctors, none of the 27 patients had clinical or radiographic evidence of asbestosis. The false-positives seemed to be due to the serratus anterior muscle mimicking the disease.

Asbestosis attorneys encourage those diagnosed with this disease to seek second opinions. Asbestosis entails scarring of lung tissue to such an extent that it cannot contract and expand normally. Like most lung disease, cigarette smoking increases the progression and severity of the disease. A false-positive is somewhat common because asbestosis appears as excessive whiteness in your lung tissue, which may be mistaken when the anterior serratus muscle overlaps with the lung, or obstructs lung detail. It is recommended that those with suspicious lung tissue get an additional high-resolution CT (HRCT) to eliminate the possibility of a false-positive.

Patients with assumed exposure to asbestos were referred from the United States Department of Labor for respiratory evaluation. All patients arrived with a diagnosis of asbestosis on the basis of their exposure to the asbestos material and chest radiographs which had been taken by a regional screening center and interpreted by a “B” reader. Often the radiographs that accompanied these patients for interpretation had grease pencil markings on the posteroanterior chest film laterally corresponding to the density of the serratus anterior muscle.

The authors became interested when radiographs from the referring centers continued to have markings outlining the normal muscular anatomy of the chest. Many of the radiographs consistently depicted the serratus muscle as pleural disease. This information was relayed to the Occupational Medical Service and forwarded to the Department of Labor.

The findings in these patients presented questions of pleural thickening vs prominence of the serratus muscle. The value of oblique chest radiographs in the diagnosis of asbestosis is in the possibility of detecting abnormalities that can lead to interventions designed to reduce asbestos-related mortality. The risks include false positives, which may result in superfluous medical expenses and anxiety.

The serratus anterior muscle is believed to be what contributed to the diagnosis of pleural disease consistent with asbestosis. The only problem existing at present is to inform radiologists and pulmonary physicians that it is imperative that the anatomy of the serratus anterior muscle be considered in the interpretation of chest radiographs when the patients have the history of exposure to asbestos material. In fact, the serratus anterior musculature should always be considered in patients with known disease that may involve the chest or any other disease that is to be ruled out, as patients may be given medical treatment when actually no disease exists. This is particularly true in patients with exposure to asbestos
These results suggest that the routine use of radiographs as a screening test in groups of subjects exposed to levels of asbestos should be re-evaluated. Positive predictive values to right anterior oblique views were only 13%-26%. The addition of HRCT to chest radiography is most useful in eliminating false-positive diagnoses of asbestos-related pleural disease.

The interpretations of chest radiographs in patients exposed to asbestos are often extremely difficult and subjective, and it is recommended that positive findings (except calcified plaques) be confirmed with HRCT.

Asbestosis attorneys at Pintas & Mullins Law Firm are constantly reviewing case studies related to asbestos exposure. If you developed an asbestos-related disease, contact one of our asbestos exposure lawyers immediately for a no-cost, no-obligation legal consultation.