Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.
An MRI (or magnetic resonance imaging) scan is a
radiology technique that uses magnetism, radio waves, and a computer
to produce images of body structures. The MRI scanner is a tube
surrounded by a giant circular magnet. The patient is placed on
a moveable bed that is inserted into the magnet. The magnet creates
a strong magnetic field that aligns the protons of hydrogen atoms,
which are then exposed to a beam of radio waves. This spins the
various protons of the body, and they produce a faint signal
that is detected by the receiver portion of the MRI scanner.
The receiver information is processed by a computer, and an image
is produced.
The image and resolution produced by MRI is quite detailed and can
detect tiny changes of structures within the body. For some procedures, contrast agents, such as gadolinium, are used to increase the accuracy of the images.
When are MRI scans used?
An MRI scan can be used as an extremely accurate
method of disease detection throughout the body. In the head,
trauma to the brain can be seen as bleeding or swelling. Other
abnormalities often found include brain aneurysms,
stroke,
tumors
of the brain, as well as tumors or inflammation of the spine.
Neurosurgeons use an MRI scan not only in defining brain anatomy
but in evaluating the integrity of the spinal cord after trauma.
It is also used when considering problems associated with the
vertebrae or intervertebral discs of the spine. An MRI scan can
evaluate the structure of the heart and
aorta, where it can detect
aneurysms or tears.
It provides valuable information on glands
and organs within the abdomen, and accurate information about
the structure of the joints, soft tissues, and bones of the body.
Often, surgery can be deferred or more accurately directed after
knowing the results of an MRI scan.
Medical Author: Benjamin Wedro, MD, FAAEM
Medical Editor: Melissa Conrad Stöppler, MD
June 2008 - In the last few months, Tiger Woods has won nine out of the 12
golf tournaments he has entered. So who cares? Whenever he tees it up, it's
Tiger against the field, and Tiger always wins. But Tiger has met his match.
While his mind was willing, his body has suffered a breakdown.
The medical story goes like this. In the midst of his latest winning streak,
Tiger ruined his left knee, tearing the anterior cruciate ligament (ACL) and
damaging the cartilage. Most people can't easily walk with this injury; Tiger
played on. In mid-April he underwent
arthroscopyto trim the damaged cartilage
and began golf practice almost immediately. Without his surgeon's blessing, he
played and won the USGA Open 2008. Only afterwards was it revealed that he had
sustained a stress fracture in his
tibia. The pain on his face could now be
understood. It is time to pay the piper. Tiger is done for the year, with knee
reconstruction surgery and months of rehab in his future.
Sciatica pain, caused by irritation of the sciatic nerve, typically radiates from the low back to behind the thigh to below the knee. Disc herniation is
A pinched nerve can be caused of a variety of conditions, for example, carpal tunnel syndrome, herniated disc, sciatica, arthritis, spinal stenosis, trauma,
Abdominal pain is pain in the belly and can be acute or chronic. Causes include inflammation, distention of an organ, and loss of the blood supply to an
Liver disease can be cause by a variety of things including infection (hepatitis), diseases such as gallstones, high cholesterol or triglycerides, blood
Dizziness is a symptom that is often applies to a variety of sensations including lightheadedness and vertigo. Causes of dizziness include low blood pressure,
Diverticulitis is a condition in which diverticuli in the colon rupture. The rupture results in infection in the tissues that surround the colon. Diverticulitis
A hematoma is a collection of blood that is outside a blood vessel. There are different areas where hematomas occur including the inside the skull, scalp,
A torn meniscus (knee cartilage) may be caused by suddenly stopping, sharply twisting, or deep squatting or kneeling when lifting heavy weight. Symptoms
Pancreatic cancer is a malignant tumor of the pancreas. Pancreatic cancer has been called a "silent" disease because early pancreatic cancer usually does
There are many causes of back pain. Pain in the low back can relate to the bony lumbar spine, discs between the vertebrae, ligaments around the spine and
Cysts are saclike structures that can occur throughout the body and usually contain a semisolid, liquid, or gaseous substance. Infections, tumors, genetic
Foot pain may be caused by injuries (sprains, strains, bruises, and fractures), diseases (diabetes, Hansen disease, and gout), viruses, fungi, and bacteria
In the U.S., more than 2,000 people are diagnosed with bone cancer every year. There are many types of bone cancer. The most common forms of bone cancer
The knee joint is composed of three compartments and ligaments which stabilize the joint. Causes of knee pain may include injury, degeneration, infrequently
Gallstones are stones that form when substances in the bile harden. Gallstones (formed in the gallbladder) can be as small as a grain of sand or as large
Shin splints result from inflammation from injury to the tendon and adjacent tissues in the front of the outer leg. Shin splints commonly occur in runners
A Baker cyst, also called a popliteal cyst, is swelling caused by knee joint fluid protruding to the back of the knee (popliteal area of the knee). Not
Temporomandibular joint disorder, or TMJ, is a disorder of the temporomandibular joint(s) that causes signs and symptoms including ear pain, bite problems,
Liver cancer is the fifth most common cancer in the world and the majority of patients with liver cancer will die within one year as a result. Patients
Angina is chest pain that is due to an inadequate supply of oxygen to the heart muscle. Angina can be caused by coronary artery disease or spasm of the
Bone spurs are pointy outgrowths of bone that develop in areas of inflammation or injury. They commonly occur on the heel and spine and may be the result
Migraine is usually periodic attacks of headaches on one or both sides of the head. These may be accompanied by nausea, vomiting, increased sensitivity
Fainting, also referred to as blacking out, syncope, or temporary loss of consciousness has many causes. Often a person will have signs or symptoms prior
Gas or "intestinal gas" means different things to different people. Everyone has gas and eliminates it by belching or farting (passing it through the rectum).
A pulmonary embolism occurs when a piece of a blood clot from deep vein thrombosis (DVT) breaks off and travels to an artery in the lung where it blocks
The spinal cord is a collection of nerves that travels from the bottom of the
brain down your back. There are 31 pairs of nerves that leave the spinal cord
and go to your arms, legs, chest and abdomen. These"...
