Detecting Asbestos Plaques using Radiology to Make Diagnoses, continued

It has to be realized that radiological criteria for plaques differ very much between various readers. In any study concerning the occurrence of plaques the criteria used for diagnosing them should be clearly stated.

If not very strict criteria are used, a considerable overdiagnosis is unavoidable. This is one possible explanation behind the different opinions about the importance of plaques.

In the general population in a society where there are no "endemic plaques", 80-90 per cent of strictly defined pleural plaques are due to occupational exposure to asbestos. However, they can be found also in persons with only low-level or sporadic exposure.

There are many normal intrathoracic and extrathoracic structures that can lead to X-ray findings which may be mistaken for pleural plaques. Here are some of the more common: Fat pads are common, especially in overweight persons.

Typically, they are even thickenings along the flanks which start apically and can be followed sometimes down to the costodiaphragmal junction. However, they can also be irregular, and plaques can at times be situated on the fat. CT scan can show the fat density.