Computed tomography or CAT scans are specialized medical X-ay tests that produce cross-sectional images of the body by passing radiation into the body, which is in turn detected by a detector and then integrated into a computer (Igbaseimokumo, p. 31). These images allow the radiologists to have an in-depth view of the area of interest allowing a clear and precise evaluation. CAT scans are common in the evaluation of the brain, neck, spine, chest, abdomen, pelvis and sinuses (Easton, p, 45). MRI (magnetic resonance imaging) on the other hand, is a medical imaging technique that has been used since the beginning of the 1980s. It uses magnetic and radio waves to visualize the detailed internal structure of the body (Leichter, p. 4).
Computed Tomography or CT scans.
CT scan is a commonly used procedure in hospitals. A CT scanning machine is a large box like machine with a short tunnel in the center. A patient lies down on a table that slides into the tunnel. Rotating around the patient are beams of X-rays that follow a spiral path and are detected by detectors that measure the amount of rays being absorbed by the body (Igbaseimokumo, p. 36). A special computer program processes the data into a two cross-dimensional images that are the displayed on the computer to be interpreted by a radiologist. Some CT scanners have the ability to recreate the two dimensional picture into three dimensional pictures so that the doctors views the pictures as if it was on the operating table.
CT scanning has completely transformed the medical field by allowing doctors to see images that could have otherwise been detected during autopsy or surgery. It is arguably one of the best tools for studying the chest, abdomen, pelvis, diagnosing various cancers, detection, diagnosis and treatment of vascular diseases and also diagnosing and treatment of spinal injuries. Occasionally, a contrast dye is administered in to the blood stream to give clear pictures prior to the scanning especially the blood vessels and the kidneys.
Some of the benefits of CT scans include:
- CT scanning has the ability to image bone, soft tissue and blood vessels all at the same time.
- It is also safe, less invasive, painless, less expensive compared to MRI, and it's also precise and accurate.
- Provides detailed images of bony structures, lungs and blood vessels.
- It's fast, can be done within five minutes and its very important in detecting internal injuries and bleeding in case of emergencies.
- Can be done even with patients with medical implants in the body.
- Poses no risk of radiation after the procedure.
- X-rays used in CT scan usually have no side effects.
However, patients could be at a risk of radiation if they are exposed for longer periods. Pregnant women are advised not undergo the procedure because of the potential risk to the unborn child especially during the first trimester still during the examination are normally sedated. Patient could also develop allergic reactions to contrast dye and can sometimes be life threatening if not treated (Igbaseimokumo, p. 61).
Magnetic Resonance Imaging (MRI)
MRI scan uses radio waves and strong magnetic field to create clear pictures of body organs, tissues and other structures that X-rays tests did not give detailed information. An MRI machine is a large tubular machine surrounded by a large magnet. Once the patient slides in the machine, radio waves are sent throughout the body (Leichter, p. 43). Movement of the radio waves upsets the atoms in the body forcing the nuclei to move into different positions. As they move back into place they emit their own radio waves that are transmitted onto a scanner and the computer creates pictures based on the signals emitted. A radiologist is then able to interpret the pictures to the patient. The process takes about 15-30 minutes and could be a little uncomfortable especially if it's the first time. The machine makes a lot of noise and sometimes some people develop claustrophobia and may need general anesthesia especially young children who may not keep still. In some cases, special contrast dye is injected into the main blood stream in order to give clear pictures of certain tissues and organs especially the bone structure. The scan itself is painless.
MRI scan creates clear pictures of the body organs in cases where X-rays tests do not give detailed information and therefore it's used mostly in detecting tumors in both the spinal cord and the brain. Unlike a CT scan which can be performed with medical implants in the body, an MRI scan cannot be done with any metal fragment inside the body. This is because MRI uses extremely strong magnet that can potentially move the medical devices or affect their function (Price, p. 22).
MRI scans have several advantages including,
- The procedure is painless and safe.
- There is no possible exposure to radiation since it does not use X-rays like CT scan.
- It has no side effects and one can return to normal duties after the scan.
- It's accurate and precise.
It however poses a few risks. Some people develop claustrophobia while under going the examination making it difficult to take clear pictures. Such patients are given general anesthesia to keep them still. Pregnant women are advised not to undergo the procedure due to the long term effects of the strong magnetic field to the unborn child. Though rarely, some people have reactions to the contrast dye which is sometimes used to get clear pictures. It is also expensive compared to CT scan.
- Uses radio waves and magnetic fields.
- The procedure takes 15-40 minutes.
- Patients can develop claustrophobia.
- Gives more detailed information in all structures
- Cannot be done to patients with any medical metal implants.
- Uses X-rays
- The procedure takes about five minutes.
- Its less expensive compared to MRI scan
- Patients may not develop claustrophobia since the procedure takes less time.
- Gives more detailed information especially in bony structures.
- Can be done to patients with medical metal implants.