Magnetic Resonance Imaging (MRI) Scan
The MRI is even more accurate than the CT scan and provides extremely clear pictures. The test is especially accurate for detecting tumors in or around the lungs, and is thus often used for diagnosing mesothelioma. The MRI is particularly superior to a CT scan in discerning a tumor’s invasion through the diaphragm (the muscle below the lung cage that enables breathing) or through the mediastinum (the region in the chest between the lungs and behind the breast bone where the heart, major blood vessels, nerve tissue, and lymph glands are congregated).
MRI scans operate with radio waves and strong magnets rather than x-rays. The energy from the radio waves is absorbed by the body and then released in a pattern that varies depending on the type of tissue or disease being studied. The pattern of radio waves given off by the tissues is translated by a computer into a very detailed image of the scanned portion of the body. The MRI not only produces cross sectional slices of the body the way a CT scanner does, it also generates slices that run parallel to the length of the body.
No preparation is required for the MRI unless the prescribing physician recommends the use of a contrast dye. In that case, the contrast-drink must be consumed prior to the test being administered. But the contrast dye is used less often for the MRI procedure than for the CT scan.
Still, MRI scans tend to be a little more uncomfortable than CT scans. For the MRI, the patient lies absolutely still on a table that moves into the tube-shaped MRI machine, which directs radio waves towards the body. The patient will hear loud clicking and other noises during the procedure, but these sounds are harmless and are no indication of a problem. Most facilities will offer earplugs to block out the noise and many will provide headphones with music to mask the noise. The procedure lasts longer than a CT scan — usually from 30 to 90 minutes. If the patient has a fear of closed-in spaces, some facilities may offer a sedative before the test. All that said, many patients become so relaxed that they actually fall asleep during the test.