Exams and Tests

Imaging Studies

Chest x-ray: In people with mesothelioma, chest x-ray may show signs of mesothelioma. However, chest x-ray has limited usefulness because the findings of mesothelioma on chest x-ray are nonspecific and observed in other diseases as well.

CT scan: The findings of CT scan are similar to those of chest x-ray but are seen better and in more detail. CT is preferred for staging the tumor.

MRI: In some people, MRI complements the findings on CT scan. MRI provides better delineation of soft tissues (better soft-tissue contrast) and may provide additional information not obtained from other studies.

Positron emission tomography (PET) scan: PET is a procedure in which a radiolabeled substance is used to measure the metabolic activity of the cells. Cancerous cells demonstrate increased metabolic activity. This procedure is being increasingly used to determine the size of the tumor and whether the tumor has spread.

Radiologic findings on x-ray, CT scan, and MRI cannot provide a clear diagnosis of mesothelioma. A history of asbestos exposure and radiologic findings may indicate the presence of mesothelioma, but it is important to stress that a diagnosis of mesothelioma cannot be made exclusively with imaging. Other diseases can look identical to mesothelioma radiographically. Tissue biopsy (a sample of cells is removed for examination under a microscope) is required for a definitive diagnosis.

Thoracoscopy: In this procedure, a small cut is made in the chest wall and a thoracoscope (flexible, lighted tube) is inserted between the two ribs. Thoracoscopy allows the health-care professional to look inside the chest and take tissue samples. A pathologist examines these samples for cancer cells. It provides a confirmatory diagnosis in 98% of people with mesothelioma.