The world of diagnostic radiology offers many imaging options, each of which has its own specific application. CT scan, MRI and ultrasound are popular choices used for diagnosing a variety of conditions and diseases. They are done in scheduled or emergency situations to best diagnose and treat the patient.
A computed tomography scan or CT scan allows the physician to examine cross-section images of the body. It presents a multi-dimensional view of the scanned area. Moderate to high levels of radiation are used in CT scanning.
Conditions Best Diagnosed or Tracked by CT Scan
CT scans focus on diagnosing conditions, which involve internal organs, soft tissue, bone and blood vessels.
CT scans are typically used to diagnose or track many of the following conditions, among others:
- Pulmonary embolism
- Abdominal pain, including inflammatory bowel disease, acute appendicitis
- Cancer, including lung, liver, kidney and pancreatic
- Trauma involving liver, spleen, bowel, lungs and kidneys
- Musculoskeletal disorders of the spine and extremities
- Lymphoma and neuroblastoma
- Congenital malformations of the heart, kidneys and blood vessels
- Cystic fibrosis
- Guidance for organ biopsy and abscess drainage
- Measuring bone density in osteoporosis
When is a CT Scan the Best Choice?
Despite the fact that a CT scan exposes the patient to radiation, there are circumstances in which it is the best diagnostic option.
- If the patient has an implanted medical device containing any metal, including a cardiac pacemaker, it stands a risk of malfunctioning if MRI is used
- Over-sized patients who are unable to safely and comfortably fit into an MRI scanner
- If a patient is unable to lie completely still for MRI
MRI or Ultrasound vs. CT Scan
There are circumstances in which it is appropriate to ask a physician if an MRI or ultrasound can be done instead of a CT scan, which involves radiation. Ultrasound can provide detailed imaging of soft-tissue areas, while MRI can image areas obscured by bone, and there is basically no risk with either of these diagnostics.
Magnetic resonance imaging or MRI uses a powerful magnetic field and radio frequency pulses to create highly detailed images. No radiation exposure is involved with MRI imaging.
Conditions Best Diagnosed by MRI
MRI is an appropriate diagnostic tool for the following, but not limited to this list:
- Soft tissue structures like brain and pelvic organs
- Reproductive organs including the male prostate and testicles and female cervix, uterus and ovaries; assesses fibroids, endometriosis, adenomyosis and uterine abnormalities for women undergoing infertility treatment
- Joints including knees and shoulders
- Chest and abdominal organs: heart, liver (including cirrhosis), biliary tract, kidneys and urinary tract, spleen, bowel, pancreas and adrenal glands
- Blood vessels: renal arteries, arteries in legs, aorta, blood vessel enlargement
- Breast cancer and implants
- Fetal assessment in pregnant women
- Diseases of bile ducts, gallbladder and pancreatic ducts
- Colorectal disease involving the small intestine, colon, rectum and anus
An ultrasound study is done using sound waves focused on the affected area of the body to produce diagnostic digital images. There is no radiation exposure involved. Ultrasound is less effective in navigating around internal obstructions, like bone, to attain a clear image.
When a physician orders a specific diagnostic test, the decision is made based upon the desired images and the benefits versus the risks of the study. In the case of a CT scan, the benefits of the information accrued from the scan often outweigh the risk of radiation exposure. It is important to discuss the best personal option with the ordering physician.