ABC's of Imaging
At Spine West we use a variety of imaging modalities to help diagnose and treat your musculoskeletal and neurologic ailments. Each imaging modality has its strengths and weaknesses. No imaging modality is perfect for all conditions or all persons. We consider several factors including the information needed, cost, convenience, and comfort to choose the most appropriate studies for our patients. Some of the imaging modalities we use include:
- CT Scans
Magnetic resonance imaging (MRI) has no radiation exposure. MRI uses magnets and radiofrequency signal emitted by excited hydrogen ions to reconstruct an image of the body part being studied. MRI is often used to see deeper structures in the body such as the spine, brain, and "inside" of joints, and to look at the "soft" tissues of the body in more detail than CT scans or x-rays. Closed MRIs are tube shaped and are often quite loud. An open sided MRI, which we have available at Spine West, uses flat plates that do not completely enclose the patient. MRIs cannot be done on people with implanted electrical devices, such as heart defibrillators and pace makers, or some folks with metal in their eyes or brains. MRI's take longer than CT scans and lying still is required for good imaging.
Ultrasound is another type of imaging we have available at Spine West. It uses sound waves to look at structures inside the body. It is safe, immediate, dynamic, and has no radiation exposure. During an ultrasound study, a transducer sends out sound waves, which differentially bounce off the tissues inside your body. The processor recreates images of the body from the reflected sound waves. Ultrasound has been used for over 50 years in medicine. It is painless, safe, and allows for real-time dynamic images of muscles, joints and tendons. It is best for evaluating more soft tissue structures such as muscles, tendons, ligaments and joint fluid. Ultrasound is also very useful to accurately place injections into joints, bursa and around nerves or tendons.
X-rays are electromagnetic waves that are differentially absorbed by various body tissues. Bones absorbs x-rays the most and appear white. Fat and other soft tissues absorb less, and look gray. Air absorbs the least, so lungs look black. The most familiar use of x-rays is evaluating for broken bones, arthritis, and joint stability. X-rays are also used for non-bone issues. For example, chest x-rays can spot pneumonia and mammograms look for breast cancer. At Spine West, we use fluoroscopy (real-time x-ray at a much lower radiation dose than conventional x-rays). The amount of radiation you get from an x-ray is small. For example, a chest x-ray gives out a radiation dose similar to the amount of radiation you're naturally exposed to from the environment over 10 days. The amount of radiation from a fluoroscopic procedure is typically a small fraction of that, equivalent to flying cross country in a plane or spending a day in the Rocky Mountains.
Computed tomography (CT) uses special x-ray equipment to make cross-sectional pictures of your body. It is used to evaluate for cancers, problems with the lungs or abdominal organs, and in the setting of trauma to evaluate for broken bones and bleeding. It also is used to image the spine in those that cannot have an MRI. The radiation exposure for a CT of the abdomen and pelvis is approximately 100x that of a chest x-ray. Interestingly, smoking a pack of cigarettes a day for a year exposes the smoker to over 5x the risk of a CT scan.
At Spine West, we have many imaging modalities on-site. We have an MRI, 2 ultrasound machines, 2 fluoroscopic x-rays machines for the convenience of our patients. This allows for more efficient diagnosis and treatment.