X-Ray vs. CT Scan vs. MRI
X-Ray vs. CT Scan vs. MRI
Injuries and Diagnostic Imaging Tests
When illness or aventura car accident injury present the possibility of internal abnormalities, diagnostic imaging techniques allow doctors to ascertain the internal conditions from a visual standpoint. Imaging tests provide a noninvasive way to confirm or rule out specific diagnoses. The most common tests used are x-rays, computed tomography (CT) scans and magnetic resonance imaging (MRIs).
X-rays, or radiographs, are the most commonly used diagnostic tool for cases involving pneumonia, chest injury, heart failure or suspected bone damage. X-rays emit electromagnetic waves which pass painlessly through the body to reflect off of photographic film positioned behind the body part needing evaluated. Depending on the density of the tissue, targeted areas of the body will absorb the radiation in varying degrees, and images on the film will appear in respective shades of light and dark. Though not very detailed, certain diagnoses, such as bone fractures, can be assessed through x-rays. On the other hand, soft tissue may appear as pockets of air, thus failing to produce a clear and concise image for the purpose of diagnosis. Some conditions, such as small tumors or pulmonary embolisms, cannot usually be detected via x-rays. X-rays are often an initial test administered for injuries and are followed up with further testing for this reason.
The Benefits and Risks of X-Rays
X-ray machines are fairly inexpensive and are widely available in most hospitals and emergency rooms. The tests last approximately ten minutes and require little preparation, aside from the removal of certain accessories, such as jewelry. Results of the test can be obtained quickly and analyzed for a preliminary diagnosis. X-rays also indicate what follow-up tests will most effectively result in a confirmed diagnosis and course of treatment. The low doses of radiation put the patient at minimal risk of exposure. However, any exposure to radiation carries health risks, including cancer.
Computed Tomography Scans
CT scans combine computer technology with x-rays to produce a highly-accurate, cross-sectional image of the internal structures of the body on a screen. This makes it possible to discern size, shape and position of anomalies including tumors, fractures, hemorrhages or hematomas. CT scans have the ability to capture more comprehensive images of bone, organs and blood vessels and are particularly effective in imaging tiny bone structures not detectable by x-rays. The National Institutes of Health funded studies conducted at the University of California, San Francisco that indicated that follow-up MRIs have proven to be more successful at detecting some brain injuries, however.
Benefits and Risks of CT Scans
CT scans provide an alternative to invasive biopsies and exploratory surgeries. They are also used to guide certain invasive procedures to ensure accurate targeting of the injured area. CT scans take 30 minutes or less, which can play a vital role in determining the existence of internal bleeding.
The levels of radiation emitted from CT scans vary. Exposure to radiation poses similar risks for cancer as does x-rays. Pregnant women need to inform medical staff of a pregnancy since radiation can harm a growing fetus. Injected contrast material needed for analyzing CT scan results can be detected in breast milk and passed onto a nursing infant as well. Certain levels of radiation can also damage ovaries. The radiation dose is left to the discretion of the referring physician. Thus, concerns related to radiation exposure should be addressed prior to the CT scan if possible. Children should avoid exposure to radiation unless the situation is medically dire.
Magnetic Resonance Imaging
MRIs also produce detailed cross-sectional images of internal structures. Unlike x-rays and CT scans, MRIs utilize magnetic feels rather than radiation. The magnetic waves cause body tissue to resonate, and a sophisticated computer records the response. MRIs are instrumental in soft tissue evaluations. For example, MRIs performed for some brain trauma cases can detect microscopic bleeding that CT scan may miss. This symptom can influence the overall diagnosis and neurological prognosis of the patient.
Functional MRIs have also been successful at detecting a disruption in activity in the default mode network area of the brain. Normally when the brain rests, neural communication is conducted in the default mode network. Some brain injuries can interfere with the normal communication in this area of the brain.
Post concussive syndrome, a collection of symptoms including dizziness, headache, light sensitivity and memory loss, can affect someone that has sustained a blow to the head. The disorder, the onset of which typically occurs in the first week, may last for several weeks or months following the time of the injury to the brain. Imaging tests cannot always result in a definitive diagnosis of post concussive syndrome, but MRIs can play an instrumental role in detecting brain abnormalities due to trauma to the head.
Benefits and Risks of MRIs
MRIs provide detailed and concise results instrumental in diagnosis an ailment or injury. Though patients may need injections to enhance the images, the test is painless and noninvasive.
Patients with metallic material in their bodies may risk distorted results. Likewise, patients with metal clips in or around the eyes or heart pacemakers should avoid MRIs. The magnet can possibly move these devices causing further injury. Similarly, the function of chemotherapy or insulin pumps can be adversely affected. Since the test can range from 30 to 90 minutes on average, medical staff needs to be nearby to intervene in the event that a patient cannot tolerate the test for reasons due to claustrophobia.
Other Diagnostic Tools
Electromyography (EMG) is an invasive technique used to measure the electrical activity between nerves and muscles. A thin needle inserted through the skin into the muscle being tested, and an electrode detects electrical activity. A monitor displays the muscle response to stimulation, such as muscle contraction. Surface electromyography (SEMG) assesses electrical activity through the placement of electrodes on the skin. Though less invasive, this technique is also less reliable in terms of accurate diagnostic information. Very little electrical activity should be detected when a muscle is at rest. Thus, the presence of activity indicates possible nerve damage.
Nerve conduction velocity (NCV) often routinely performed in addition to an EMG, evaluates the speed with which an electrical signal travels through a nerve. The electrodes emit a subtle electrical impulse to stimulate the nerve. The response time of the muscle indicates nerve health or damage, depending on how quickly or delayed the reaction. Nerve damage can cause changes to temperature and pain perceptions or generate tingling sensations that interfere with normal functioning. Altered pain perception poses risks to health and well-being.
The Positron emission tomography (PET) scan is an imaging test designed to identify diseased tissue in the body. A special dye containing radioactive tracers is inject into the arm, and the scan provides information on blood flow, glucose metabolism, oxygen use and other processes. This scan is primarily used to detect heart issues, signs of cancer and problems with the central nervous system. PET scans are not usually used in injury cases.
Chiropractor, Physical Therapist or Orthopedic Surgeon?
When an trauma or injury is sustained, an accurate diagnosis is necessary to obtain the most effective follow-up care. Diagnosis must be obtained from a medical expert trained in primary care, able to interpret x-ray, CT scan and MRI results and licensed to diagnose a patient in an official capacity. According to the American Physical Therapy Association, physical therapists can diagnose movement dysfunction but usually require a referral from a primary care physician before seeing a patient. Patients need to seek out professional advice from medical doctors or chiropractors regarding injuries and referrals to physical therapy, surgeons or specialists.
Medical Doctor Versus a Chiropractor
Concerns regarding internal injury or infectious disease should be managed by a medical doctor. Injuries resulting in structural imbalance and muscle or ligament pain can be addressed by a chiropractor. Ultimately, both types of doctors should possess training in diagnosing internal and structural abnormalities and are equally responsible for providing quality medical treatment, but chiropractors possess specific training in the musculoskeletal system. Chiropractic care centers around therapeutic exercises, diet and lifestyle counseling and hands-on practices, including spinal manipulation. Spinal manipulation aims to restore joint mobility to joints limited in function due to tissue injury. Tissue injuries can be sustained by a single traumatic event or result from repetitive stresses on joints. Tissue injuries cause pain, inflammation and impairs functional movement. Spinal manipulation should relieve pain and rarely causes discomfort. Some rehabilitative exercises can occasionally result in mild discomfort for several hours following treatment.
Physical Therapist Versus Orthopedic Surgeon
Physical therapists and orthopedic surgeons both provide services in health care settings and work with patients that have some form of physical discomfort or difficulty. . A proper diagnosis from an expert trained in primary care will indicate an appropriate course of action for seeking treatment. Physical therapy should be considered before opting for surgery whenever possible since surgery can result in permanent, irreversible changes to the body. In the event that physical therapy proves unhelpful, orthopedic surgery can be an option, whereas opting for physical therapy for a specific musculoskeletal problem following surgical intervention may not be possible.
Physical therapy typically provides care for managing chronic physical conditions, such as cerebral palsy, or rehabilitation from an injury. Physical therapists utilize several techniques to foster improved physical mobility in the injured area. Techniques may include:
- Massage therapy
- Exercise regimens
- The use of adaptive equipment
Similarly, orthopedic surgeons usually require a referral from a primary care doctor in order to provide treatment to patient. Patients usually have an existing condition or injury concerning the musculoskeletal system in order to be referred to an orthopedic surgeon. Instead of the physical rehabilitation of an injured area, orthopedic surgeons perform operations to restore physical function or improve mobility. Common surgeries include:
- Rotator cuff repair
- Total shoulder replacement
- Total hip replacement
- Spine surgery
- Endoscopic carpal tunnel surgery
The Bottom Line
Any injury to the musculoskeletal system needs to be taken seriously and immediately assessed by a qualified medical professional. If left untreated, these injuries can lead to physical deformation, movement dysfunction and other musculoskeletal system complications. Proper diagnosis can be obtained through imaging techniques that provide an internal view of the body from a noninvasive standpoint. Most commonly used are x-rays, CT scans and MRIs, depending on the type of injury. Expert interpretation of the results can produce a confirmed diagnosis, indicate specific treatment and avoid more invasive diagnosing techniques such as exploratory surgery.
When performed correctly, these diagnostic tools pose little risk to the patient. Since some of the tests involve the use of radiation energy, precautions need to be taken to protect a pregnant woman’s unborn child, nursing infants and any child with an injury that may warrant imaging tests. Doses of radiation can also affect women differently than men. Thus, an in-depth discussion of possible repercussions of the tests should take place between the medical expert issuing them and the patient in question.
The imaging test and the type of injury involved directly impact the subsequent diagnosis. Because of this, careful attention must be given to details surround the injury, including what caused the trauma and the location of the injury, to determine the necessary tests required for proper diagnosis and treatment. Likewise, the confirmed diagnosis and recommended treatment indicate whether the injury warrants the care of a chiropractor, physical therapist or orthopedic surgeon. The professional should be trained to assess the injury from a medical standpoint and determine the best course of action to restore or improve physical mobility or relieve pain. Ultimately, practice and treatment needs to have one priority in common: the patient.