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Brain Injury
Traumapedia
The Traumapedia is a glossary of terms and procedures commonly used in brain injury cases.
The Traumapedia was created by the American Trauma Society and the Trauma Survivors Network.
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Medical Imaging/Radiology
Magnetic Resonance Imaging (MRI)
DEFINITION:
MRI is a non-invasive procedure that uses powerful magnets and radio waves to construct pictures of the body.
Unlike conventional radiography and computed tomographic (CT) imaging, which make use of potentially harmful radiation (x-rays), MRI imaging is based on the magnetic properties of atoms. A powerful magnet generates a magnetic field roughly 10,000 times stronger than the natural background magnetism from the earth. A very small percentage of hydrogen atoms within a human body will align with this field.
When focused radio wave pulses are broadcast towards the aligned hydrogen atoms in tissues of interest, they will return a signal. The subtle differences in that signal from various body tissues enables MRI to differentiate organs, and potentially contrast benign and malignant tissue.
Any imaging plane (or slice) can be projected, stored in a computer, or printed on film. MRI can easily be performed through clothing and bones. However, certain types of metal in the area of interest can cause significant errors, called artifacts, in the reconstructed images.
How the test is performed
Since MRI makes use of radio waves very close in frequency to those of ordinary FM radio stations, the scanner must be located within a specially shielded room to avoid outside interference. The patient will be asked to lie on a narrow table which slides into a large tunnel-like tube within the scanner.
In addition, small devices may be placed around the head, arm, or leg, or adjacent to other areas to be studied. These are special body coils which send and receive the radio wave pulses, and are designed to improve the quality of the images. If contrast is to be administered, an IV will be placed, usually in a small vein of the hand or forearm. A technologist will operate the machine and observe you during the entire study from an adjacent room.
Several sets of images are usually required, each taking from 2 to 15 minutes. A complete scan, depending on the organs studied, sequences performed, and need for contrast enhancement may take up to one hour or more. Newer scanners with more powerful magnets utilizing updated software and advanced sequences may complete the process in less time.
How to prepare for the test
No preparatory tests, diets, or medications are usually needed. An MRI can be performed immediately after other imaging studies. Depending on the area of interest, the patient may be asked to fast for 4 - 6 hours prior to the scan.
MRI also should not be used for people with metallic objects in their bodies, such as:
Sheet metal workers, or persons with similar potential exposure to small metal fragments, will first be screened for metal shards within the eyes with x-rays of the skull.
The patient will be asked to sign a consent form confirming that none of the above issues apply before the study will be performed.
WHY THE TEST IS PERFORMED:
An MRI can provide additional imaging information for the clinician based upon its superior tissue contrast resolution. Combined with other imaging methods, a more definitive diagnosis can be given in the work up of a patient's disease.
Sequences performed with intravenous contrast may provide additional data about the blood vessels within masses.
Adapted from the National Library of Medicine.
Tag
Pain and its Management
Visual Analog Scale (VAS)
Pain is a subjective experience, meaning that it is different for different people. This makes the measurement of pain a difficult task. However, pain is an important marker for the presence of, or changes in, a disease. It has even been called the “fifth vital sign” in addition to pulse, blood pressure, respiration, and temperature. Providers use the Visual Analog Scale (VAS) in an attempt to get a standard measure of pain. You may be asked to rate your pain on a 0 (no pain) to 10 (worst pain imaginable) scale in order to measure your current pain level. Although it can be frustrating and difficult to give your pain a number, it is important to get an ongoing assessment of pain from your point of view. This measure will be used over time to look for changes in pain level. It may also help doctors decide whether or not treatments are working.
Example of a Visual Analog Scale
(VAS): No pain 0 1 2 3 4 5 6 7 8 9 10 Worst pain imaginable
The National Comprehensive Cancer Network (NCCN) has representative samples of three types of pain intensity rating scales, including the VAS, at: http://www.nccn.org
A separate scale using facial expressions has proven to be a reliable way for young children to express their level of pain. The hyperlink below will direct you to a web page with a sample of such a visual scale. http://www.cancer.gov/cancertopics/youngpeople/page7.
Medical Imaging/Radiology
X-Rays
DEFINITION:
X-rays are a form of electromagnetic radiation, just like visible light. In a health-care setting, x-rays are emitted by a machine as individual "particles" (photons) that pass through the body and then get detected by a sensitive film. Structures that are dense (such as bone) will block most of the photons, and will appear white on developed film. Structures containing air will be black on film, and muscle, fat, and fluid will appear as shades of gray. Metal and contrast media (intravenous or oral contrast) blocks almost all the photons and will appear bright white.
How the test is performed
The test is performed in a hospital radiology department or in the health care provider's office by an x-ray technologist. The positioning of the patient, x-ray machine, and film depends on the type of study and area of interest. Multiple individual views may be requested.
Much like conventional photography, motion causes blurry images on radiographs, and thus, patients may be asked to hold their breath or not move during the brief (approximately 1 second) exposure.
How the test will feel
There is no discomfort from x-ray exposure. Patients may be asked to stay still in awkward positions for a short period of time.
WHAT THE RISKS ARE:
During a single radiograph, a small fraction of the x-rays pass right through the body. The remaining photons are absorbed by tissues in the body. The energy of the absorbed photons can break apart (ionize) compounds, and this may cause cell damage. Most cell damage is soon repaired. However, some is permanent.
For the exposures encountered in conventional radiography, the risk of cancer or heritable defects (due to damaged ovarian cells or sperm cells) is very low. Most experts feel that this low risk is largely outweighed by the benefits of information gained from appropriate imaging. X-rays are monitored and regulated to provide the minimum amount of radiation exposure needed to produce the image.
Young children and a developing fetus carried by pregnant women are more sensitive to the risks of x-rays. Women should tell health care providers about suspected pregnancy. Adapted from the National Library of Medicine.
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Trauma Survivors Network
The Trauma Survivors Network is a community of patients and families who are looking to connect with one another and rebuild their lives after a serious injury. The American Trauma Society, the leading organization advocating for the injured and their families, in partnership with hospitals around the country, is committed to growing the Trauma Survivors Network by providing the programs and resources patients and families tell us they need to manage their recovery and improve their lives. The underlying goal in all of these programs and resources is helping trauma patients and their families connect and rebuild their lives following a serious injury.
In order to achieve this goal, the American Trauma Society is committed to:
- Providing valuable, practical information and referrals
- Connecting survivors with peer mentors and support groups
- Enhancing survivor skills to manage day to day challenges
- Developing on-line communities of support and hope for trauma survivors and their families and friends
- Training health care providers to deliver the best care and support to patients and their families and friends
The Trauma Survivors Network offers its services in collaboration with local trauma centers.
American Trauma Society Centers located in Tennessee
The Brain Injury Association of Tennessee (BIAT) is an awareness and advocacy organization dedicated to improving the lives of TBI survivors and their caregivers.
BIAT does not provide medical diagnoses, treatments, or advice. All medical treatments should be discussed with your provider.
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