CT Scans, MRI's and PET Scans Help Diagnose Mesothelioma Tumors
Because mesothelioma is a rare disease, it may be misdiagnosed by the everyday physician. Often, it is necessary to find a specialist who has treated numerous mesothelioma patients. A history of asbestos exposure will be an important factor in the physician's diagnostic plan, which generally includes imaging tests, such as x-rays, CT, MRI, or PET scans and tissue and fluid sampling.
X-Rays as Preliminary Step in Mesothelioma Diagnosis
A chest x-ray may indicate irregular thickening of the pleura or the thin covering that protects and cushions the lungs. It may also show pleural calcifications (mineral deposits), lowering of the lung fissures (spaces between the lobes of the lungs) and accumulation of fluid in the lungs (pleural effusion) or in the abdomen (ascites). These may be ominous signs leading to a mesothelioma diagnosis.
CT, MRI, and PET Scans for Mesothelioma Diagnosis and Tumor Detection
A computed tomography or CT scan is useful in determining the location, size and extent of cancer such as mesothelioma. It is a special radiographic technique that uses a computer to combine multiple x-ray images into a two dimensional cross-sectional x-ray image. A machine rotates 180 degrees around the patient's body, sending out a thin x-ray beam at numerous points. Crystals at the opposite points of the beam pick up and record the absorption rates of the varying thickness' of tissue and bone. The computer turns the information into a detailed picture. The CT scan allows a radiologist to see distinct aspects of the lungs and pleura to better advantage than the x-ray.
Magnetic resonance imaging (MRI) scans use magnetic fields, radio waves, and a computer to create images of selected areas of the body. MRI images tend to be quite clear and are superior to routine x-ray images.
Positron emission tomography (PET) scans use cameras and tracers to form images that indicate biological changes and detect extremely small cancerous tumors. PET scans often provide even more information than CT or MRI scans.
Mesothelioma Tissue and Fluid Samples
A needle may be inserted into the chest cavity to remove fluid for sampling purposes. The same method is used to extract fluid samples from the abdomen or pericardium. Microscopic and chemical examination of the fluid can be essential to determine whether cancer cells are present.
Tissue samples may be obtained through surgical techniques. In "thoracoscopy", a thin telescopic instrument (thoracoscope) fitted with a lighting system is inserted through a puncture in the chest wall. The physician can see the tumor and sample it using a forceps-like tool.
Special stains or electron microscopy can aid tissues analysis. The most common stains include acid-Schiff diastase, hyaluronic acid, mucicarmine, CEA, and Leu M1. These "immunohistochemical" procedures are useful to ensure an accurate mesothelioma diagnosis.