Friday, April 30, 2010
MRI Benefits
MRI is a noninvasive imaging technique that does not involve exposure to ionizing radiation. MRI images of the heart are generally clearer and more detailed than with some other imaging methods. This detail makes MRI an invaluable tool in early diagnosis and evaluation of cardiac abnormalities, especially those involving the heart muscle. MRI has proven valuable in diagnosing a broad range of conditions, including cardiac anatomical anomalies (congenital defects, etc.), functional abnormalities (valve failure, etc.), tumors and ischemic and degenerative conditions. The procedures performed with MRI can help physicians evaluate both the structure of an organ and how it is working. It enables the discovery of abnormalities that might be obscured by bone with other imaging methods. The contrast material used in MRI exams is less likely to produce an allergic reaction than the iodine-based materials used for conventional x-rays and CT scanning. Cardiac MRI allows physicians to quickly examine the structures and function of the heart and major vessels, without the risks associated with traditional, more invasive procedures.
MRI Risks
The MRI examination poses almost no risk to the average patient when appropriate safety guidelines are followed. If sedation is used, there are risks of excessive sedation. The technologist or nurse monitors your vital signs to minimize this risk. Although the strong magnetic field is not harmful in itself, implanted medical devices that contain metal may malfunction or cause problems during an MRI exam. There is a very slight risk of an allergic reaction if contrast material is injected. Such reactions usually are mild and easily controlled by medication. If you experience allergic symptoms, a radiologist or other physician will be available for immediate assistance. Nephrogenic systemic fibrosis is currently a recognized, but rare, complication of MRI believed to be caused by the injection of high doses of MRI contrast material in patients with very poor kidney function.
CT Benefits
CT scanning is painless, noninvasive and accurate. A major advantage of this imaging procedure is its ability to image bone, soft tissue and blood vessels all at the same time. Unlike conventional x-rays, CT scanning provides very detailed images of many types of tissue as well as the lungs, bones, and blood vessels. These examinations are fast and simple; in emergency cases, they can reveal internal injuries and bleeding quickly enough to help save lives. CT has been shown to be a cost-effective imaging tool for a wide range of clinical problems. It is less sensitive to patient movement than MRI. A CT scan can be performed if you have an implanted medical device of any kind, unlike MRI. This imaging modality provides real-time imaging, making it a good tool for guiding minimally invasive procedures such as needle biopsies and needle aspirations of many areas of the body, particularly the lungs, abdomen, pelvis and bones. A diagnosis determined by CT scanning may eliminate the need for exploratory surgery and surgical biopsy. No radiation remains in a patient's body after a CT examination. X-rays used in CT scans usually have no immediate side effects.
CT Risks
There is always a slight chance of cancer from excessive exposure to radiation. However, the benefit of an accurate diagnosis far outweighs the risk. The effective radiation dose from this procedure ranges from approximately two to 10 mSv, which is about the same as the average person receives from background radiation in 8 months to three years. As with any radiologic procedure, women should always inform their physician and x-ray or CT technologist if there is any possibility that they are pregnant. CT scanning is, in general, not recommended for pregnant women unless medically necessary because of potential risk to the baby. Nursing mothers should wait for 24 hours after contrast material injection before resuming breast-feeding. The risk of serious allergic reaction to contrast materials that contain iodine is extremely rare, and radiology departments are well-equipped to deal with them. Because children are more sensitive to radiation, they should have a CT study only if it is essential for making a diagnosis and should not have repeated CT studies unless absolutely necessary.
Additional Risk Minimizers
The use of high-speed x-ray film that requires only very small amounts of radiation to produce an optimal image. Technique standards have been established by national and international guidelines have been designed and are continually reviewed by national and international radiology protection councils. Modern, state-of-the-art x-ray systems have very tightly controlled x-ray beams with significant filtration and x-ray dose control methods. This contributes the minimization of scatter or stray radiation and those parts of a patient’s body not being imaged receive minimal exposure.
X-ray Benefits
X-ray imaging is useful to diagnose bone injury and disease, such as fractures, bone infections, arthritis, and cancer. Because x-ray imaging is so fast and easy, it is particularly useful in emergency diagnosis and treatment. X-ray equipment is relatively inexpensive and widely available in physician offices, ambulatory care centers, nursing homes, and other locations. So examinations are usually convenient for both patients and physicians.
Wednesday, April 28, 2010
X-ray Risks
X-rays are a type of invisible electromagnetic radiation and create no sensation when they pass through the body. Modern x-ray techniques use only a fraction of the x-ray dose required in the early days of radiology.
Special care is taken during x-ray examinations to ensure maximum safety for the patient by shielding the abdomen and pelvis with a lead apron, with the exception of those examinations in which the abdomen and pelvis are being imaged. Women should always inform their doctor or x-ray technologist if there is any possibility that they are pregnant.
During a procedure, a patient is exposed to approximately 20 milliroentgen (one-thousandth of a roentgen) of radiation. This compares with the 100 milliroentgens of radiation we are all exposed to each year from sources such as the ultraviolet rays of the sun and the traces of uranium found in the soil.
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