New techniques for diagnosis.

• Magnetic Resonance Imaging (MRI)

MRI scans are most often used to determine the extent of tumor prior to aggressive treatment. Because they provide images in multiple planes, they are better able to identify tumors as opposed to normal structures. They are also more accurate than CT scans in assessing enlargement of the mediastinal lymph nodes (those lymph nodes which lie between the two lungs), as well as a clear diaphragmatic surface, both of which play an important role in surgical candidacy.

• Positron Emission Tomography (PET)

PET imaging is now becoming an important part of the diagnosis and evaluation of mesothelioma. While PET scans are more expensive than other types of imaging, and are not always covered under insurance, they are now considered to be the most diagnostic of tumor sites, as well as the most superior in determining the staging of mesothelioma. Further explanation of PET scans.


• CT/PET


For patients who may be candidates for aggressive multimodality treatment (surgery, chemotherapy and radiation), accurate clinical staging is extremely important. Integrated CT/PET imaging provides a relatively new tool in this respect, and has become the imaging technique of choice for determining surgical eligibility. By combining the benefits of CT and PET (anatomic and metabolic information) into a single scan, this technology can more accurately determine the stage of the cancer, and can help identify the best treatment option for the patient. Read about a study of CT-PET imaging in preoperative evaluation of patients with malignant pleural mesothelioma.

A needle biopsy of the mass, or the removal and examination of the fluid surrounding the lung, may be used for diagnosis, however, because these samples are sometimes inadequate as far as determining cell type (epithelial, sarcomatous, or mixed) or because of the unreliability of fluid diagnosis, open pleural biopsy may be recommended. In a pleural biopsy procedure, a surgeon will make a small incision through the chest wall and insert a thin, lighted tube called a thoracoscope into the chest between two ribs. He will then remove a sample of tissue to be reviewed under a microscope by a pathologist. In a peritoneal biopsy, the doctor makes a small incision in the abdomen and inserts a peritoneoscope into the abdominal cavity.

Once mesothelioma is suspected through imaging tests, it is confirmed by pathological examination. Tissue is removed, put under the microscope, and a pathologist makes a definitive diagnosis, and issues a pathology report. This is the end of a process that usually begins with symptoms that send most people to the doctor: a fluid build-up or pleural effusions, shortness of breath, pain in the chest, or pain or swelling in the abdomen. The doctor may order an x-ray or CT scan of the chest or abdomen. If further examination is warranted, the following tests may be done:

• Video-Assisted Thoracoscopic Surgery (VATS)

Over the past decade, the use of video-assisted thoracic surgery (VATS) has become one of the most widely used tools in the diagnosis of mesothelioma. Biopsies of the pleural lining, nodules, masses and pleural fluid can now easily be obtained using this minimally invasive procedure, and other therapies such as pleurodesis (talc) for pleural effusions can be done concurrently.While the patient is under general anesthesia, several small incisions or “ports” are made through the chest wall. The surgeon then inserts a small camera, via a scope, into one incision, and other surgical instruments used to retrieve tissue samples into the other incisions. By looking at a video screen showing the camera images, the surgeon is able to complete whatever procedures are necessary

In many cases, this video-assisted technique is able to replace thoracotomy, which requires a much larger incision to gain access to the chest cavity, and because it is minimally invasive, the patient most often has less post-operative pain and a potentially shorter recovery period.