Why MRI Is Performed
Magnetic Resonance Imaging (MRI) is non-invasive, does not use X-ray radiation, and is one of the best tests for diagnosing lesions and abnormalities in the body. It is able to provide a higher contrast detail than a computed tomography (CT) scan. For this reason, it plays a vital role in identifying and finding many forms of cancer, certain brain tumors, sports injuries, heart disease, and vascular disease.
MRI helps detect abnormalities in most parts of the body including:
Typical indications for an MRI of the brain include headaches, dizziness, visual changes, hearing loss, seizures, nausea, history of cancer, autoimmune disease, and tingling or numbness in extremities. MRI of the brain can help detect tumors and other lesions, metabolic disorders, and demyelinating diseases like multiple sclerosis.
MRI helps distinguish differences between lymph nodes and blood vessels. Typical indications for an MRI of the neck include enlarged lymph nodes or a palpable mass. MRI of the neck can help detect tumors and other lesions, vascular abnormalities, and structural abnormalities.
Typical indications for an MRI of the spine include back pain, numbness or tingling in extremities, history of cancer, and loss of bladder or bowel control. MRI of the spine can help detect herniated or bulging discs, arthritic changes, tumors and other lesions, differences between a postoperative scar or recurrent disc, and structural abnormalities.
In the past, it was difficult to obtain diagnostic pictures of the thorax with MRI due to heart and breathing motion. However, MRI has improved its capability to take pictures by using a set of cardiac leads to monitor heart rhythms and acquire pictures with a "snapshot" eliminating heart motion. Breath-hold imaging utilizes ultrafast techniques while a patient holds his/her breath to acquire motion-free pictures. Typical indications for a MRI of the thorax include history of cancer and a questionable mass. MRI of the thorax can help detect metastatic disease, aortic aneurysms, and aortic dissections.
MRI is currently improving methods for evaluating the heart. While cardiac gating reduces heart motion and allows visualization of heart structures, coronary arteries can still be difficult to evaluate. Typical indications for a MRI of the heart include congenital and acquired heart disease.
MRI’s ability to differentiate water, fat, and silicone makes it the procedure of choice for evaluating silicone breast implants or residual silicone from removed implants. MRI of the breast for cancer detection or screening is currently being developed.
With the advent of breath-hold imaging techniques and new equipment (coils), MRI is increasingly used to evaluate the liver, spleen, kidneys, and pancreas. Typical indications for an MRI of the abdomen include history of cancer, pain, loss of organ function, bleeding, cirrhosis of the liver, and hepatitis. MRI of the abdomen can help detect enlarged lymph nodes, metastatic disease, tumors and other lesions, aneurysms, and structural abnormalities.
MRI of the pelvis is increasingly used to evaluate the uterus, cervix, ovaries, bladder, fetus, and placenta in women – and the prostate, bladder, penis, and scrotum in men. Typical indications for an MRI of the pelvis include cancer staging, pain, palpable masses, and pregnancy complications. MRI of the pelvis can help detect enlarged lymph nodes, fibroids, ovarian masses, prostate cancer staging, metastatic disease, testicular cancer, and structural abnormalities.
MRI is able to evaluate the shoulder, wrist, knee, ankle, and feet with exquisite detail. Typical indications for an MRI of a joint or soft tissue include pain, swelling, weakness, palpable mass, or decrease in range in motion. MRI of the joints and soft tissue can help detect torn ligaments, torn cartilage, edema (swelling), arthritic changes, tumors, lesions, osteomyelitis, and structural changes.
Magnetic Resonance Angiography (MRA)
MRI is now able to utilize the blood as its own contrast agent to evaluate the blood vessels of the head and neck. This technique is known as magnetic resonance angiography (MRA). MRA can evaluate blood vessels of the head and neck without injecting the patient with a contrast agent. This non-invasive technique requires only one additional set of pictures taken in addition with a standard MRI exam. MRA of the head and neck can help detect vessel narrowing (stenosis), blood vessel blockage, cerebral aneurysm, arteriovenous malformation (AVM), and blood vessel dissection.
Contrast Enhanced Magnetic Resonance Angiography (CE-MRA)
CE-MRA is a relatively new technique utilizing an injected MRI contrast media (Gd-DTPA) into the blood stream while simultaneously acquiring MRA pictures. CE-MRA is now utilized for the evaluation of blood vessels in the thorax, abdomen, pelvis, and legs.