Diagnostic imaging plays a central role in disease management and the detection of injuries. Many of the exams performed are unique in that they allow doctors to see inside the body without invasive explorative surgery. Several different imaging exams can be used to provide this view including MRI, CT, Ultrasound and X-ray. Here are some of the types of imaging exams your doctor might order and how each one differs from the other.
Magnetic Resonance Imaging (MRI)
Magnetic resonance imaging (MRI) is a widely used procedure that utilizes a strong magnetic field and radio waves to produce comprehensive images of the organs and tissues in the body. MRI scans are different from CT scans and X-rays since they do not use harmful ionizing radiation. Instead, a large magnet, radio waves, and a computer produce detailed cross-sectional pictures of internal structures and organs of the body. Due to their closed, confined structure, traditional MRIs can sometimes be a source of anxiety for some patients. Newer types of MRI machines such as the open and the upright MRI offer an alternative option for patients who otherwise would rather not have a traditional MRI as they are better suited for younger patients, those who are claustrophobic, obese or have limited mobility.
Computer Tomography (CT)
Computed tomography (CT) is the diagnostic imaging test that captures detailed images of the human body’s internal organs, soft tissue, bones, and blood vessels. The cross-sectional images produced during a CT scan are reformatted in various planes, and can even be created as three-dimensional images (3D Imaging) viewed on a computer monitor. CT is a fast, painless process that is noninvasive and helps yield accurate findings. During a CT scan, the patient lies still on a table that passes slowly through the center of a big donut-shaped x-ray machine. The length of a CT procedure is based on the size of the area being scanned, but it typically lasts only a few minutes to half an hour.
An x-ray is a painless medical imaging test that is primarily used to diagnose or monitor disorders, injuries, and abnormal growths in bones, soft tissues, the chest and abdomen. X-ray images are produced using a small dose of ionizing radiation which creates two-dimensional pictures of the body structures in a digital image format that can be shared with physicians electronically. Although there have been many advances in imaging technology, the x-ray remains the most common and widely used method of imaging techniques.
Ultrasound imaging (also known as sonography) is a diagnostic imaging tool used to examine internal body structures. It relies on high-frequency sound waves that are transmitted from a probe that is directed at the tissue being examined. These sound waves create the 3D representation of the area being imaged that can be used for diagnostic or treatment purposes. Ultrasound imaging can show things that a still image like an X-ray cannot, such as blood flow or organ movement. This makes then ideal for imaging abdominal and pelvic organs, musculoskeletal and vascular systems, or for imaging a baby in the womb.
Susceptibility-weighted Imaging (SWI)
Susceptibility-weighted Imaging (SWI) has proven to play a prominent role in determining brain injuries especially in traumatic brain injury (TBI) cases following an injury or accident and has risen as one of the most widely used imaging techniques to identify and treat traumatic brain injuries. In the acute setting, early diagnosis and aggressive management using SWI to identify cerebral and cranial problems may prevent secondary injury from the complications of brain injury.
Diffusion Tensor Imaging (DTI)
Diffusion Tensor Imaging (DTI) is an MRI-based neuroimaging method that makes it possible to identify the location, anisotropy, and orientation of the brain’s white matter areas. It is a comparatively new imaging procedure exclusively developed to inspect the white matter present in the brain. Just like an X-ray may inform the radiologist about a fracture or an MRI reveals a torn ligament, a radiologist can use the DTI information to identify numerous kinds of conditions such as cerebrovascular accidents (CVA or “stroke”), multiple sclerosis (MS) and encephalopathy.