Diagnostic imaging at Greater Rochester Orthopaedics
An arthrogram is often used to help diagnose the cause of unexplained joint pain. A contrast iodine solution is injected into the joint area to help highlight the joint structures, such as the ligaments, cartilage, tendons and joint capsule. Several X-rays of the joint are taken, using a fluoroscope, a special piece of X-ray equipment that immediately shows the image. You may be asked to fast prior to the exam. During the examination, you may be asked to move the joint into various positions as the images are taken. It is normal to experience some discomfort or tingling during the procedure. If you are or may be pregnant, or are allergic to iodine or shellfish, notify your physician; you may be at a higher risk of complications.
A bone scan is a more lengthy procedure and involves two parts. First, a small amount of radioactive material is injected and allowed to work its way through the bloodstream to be absorbed by the bones. After the injection, the waiting period is approximately three hours. The actual scan takes place after this time and detects any areas of uptake, producing a series of pictures that are used to detect bone growth, suspected fractures that are difficult to see on regular x-rays, tumors or infections. No preparation is required for this test, but bone scans should be avoided by pregnant women.
Computed Tomography (CT Scan)
A CT scan (computed tomography) combines X-rays with computer technology to produce a more detailed, cross-sectional image of your body. It may be ordered if your doctor suspects a tumor or a fracture that doesn’t appear on X-rays (such as in your collarbone or pelvis) or if you’ve had severe trauma to the chest, abdomen, pelvis or spinal cord. The process is painless. You lie motionless on a table as it slides into the center of the cylinder-like CT scanner. An X-ray tube slowly rotates around you, taking many pictures from all directions. A computer combines the images to produce a clear, two-dimensional view on a television screen. You may need to drink or be injected with barium sulfate or a dye so that certain parts of your body can be seen more clearly. The drink has a chalky taste and may make you feel nauseous; a dye injection may be moderately painful. Tell your doctor if you are pregnant before undergoing a CT scan.
A discography is a test used to determine whether the discs, the cushioning pads that separate the bones of the spine, are the source of back pain. It may be performed before surgery to positively identify the painful disc(s).
Before the procedure begins, you will be given antibiotics and relaxation medications through an IV line. Medication is used to numb the skin over the test site. During the procedure, the doctor inserts a needle into one or more discs and injects a contrast dye. You’ll feel pain when the dye is introduced into the problem disc. Afterward, a CT scan will show any changes in the disc size or shape. You may experience some muscle discomfort after the procedure; your doctor can prescribe pain relievers to ease the discomfort.
No special preparations are required for this test.
An orthopaedist who suspects that you have a blockage in the blood vessels of your legs or arms may order an ultrasound test. An ultrasound uses high-frequency sound waves that echo off the body. This creates a picture of the blood vessels. The Doppler audio system transmits the "swishing" sound of the blood flow. This is a noninvasive test that has no side effects.
A clear jelly is applied to the skin over the blood vessels being tested. The technician uses a sensor that looks like a microphone. The sensor is placed against the skin and moved up and down across the area being tested. The technician will apply pressure every few inches to see if the blood vessels change their shape. The test takes about 30 minutes, and most people experience no pain or discomfort.
An electromyography (EMG) records and analyzes the electrical activity in your muscles. It is used to learn more about the functioning of nerves in the arms and legs. For example, a fracture of the upper arm bone (humerus) may tear or pinch the radial nerve. An EMG can be used to identify the damage if nerve function doesn’t return within 4 months of the injury.
During an EMG, small, thin needles are placed in the muscle to record the electrical activity. When the needles are inserted, you may feel some pain and discomfort. The doctor will ask you to relax the muscle and then to tense it slightly. The electrical signals generated by your muscle are broadcast on a TV-like screen. When the needles are removed, you may experience some soreness and bruising, but this will disappear in a few days. There are no long-term side effects. If you are taking blood-thinning medications, have lung disease or are at risk for infection, tell the physician who is conducting the test. On the day of the test, do not put any lotions or creams on the area to be tested and do not wear any jewelry. Usually, you can get the results immediately after the test.
Magnetic Resonance Imaging (MRI)
An MRI (magnetic resonance image) uses magnetic fields and a sophisticated computer to take high-resolution pictures of your bones and soft tissues, resulting in a cross-sectional image of your body. It can be used to help diagnose torn muscles, ligaments and cartilage, herniated disks, hip or pelvic problems and other conditions. As with a CT scan, you lie on a table that slides into the tube-shaped MRI scanner. The MRI creates a magnetic field around you, then pulses radio waves to the area of your body to be imaged. The radio waves cause your tissues to resonate. A computer records the rate at which your body’s various parts (tendons, ligaments, and nerves) give off these vibrations, and translates the data into a detailed, two-dimensional picture. You won’t feel any pain while undergoing an MRI, but the machine may be noisy. An MRI takes 30 to 90 minutes, and is not available at all hospitals. Tell your doctor if you have implants, metal clips or other metal objects in your body before you undergo an MRI scan.
Involves the injection of a dye or contrast media into the spinal canal; a specific x-ray study that also allows careful evaluation of the spinal canal and nerve roots.
Nerve Conduction Study (NCS)
Nerve conduction studies are often done along with an electromyogram to determine if a nerve is functioning normally. It may be recommended if you have symptoms of carpal tunnel syndrome or ulnar nerve entrapment. The doctor conducting the test will tape wires (electrodes) to the skin in various places along the nerve pathway. Then the doctor stimulates the nerve with an electric current. As the current travels down the nerve pathway, the electrodes placed along the way capture the signal and measure its speed. In healthy nerves, electrical signals can travel at speeds of up to 120 miles per hour. If the nerve is damaged, however, the signal will be slower and weaker. By stimulating the nerve at various places, the doctor can determine the specific site of the injury. Nerve conduction studies also may be used during treatment to test the progress being made. Although you may initially be startled by the suddenness of the stimulation, it is not usually painful and most people are comfortable during the testing procedure. The shock is similar to one received when you touch a doorknob after walking across carpeting.
An ultrasound is a procedure that bounces high-frequency sound waves off an area to be examined and captures the returning “echoes” as images. Ultrasounds have significantly improved over the years in their diagnostic capabilities, and these tests are now used for a variety of conditions. In the orthopaedic setting, ultrasounds can be used to detect the presence or absence of blood flow in the legs if a blood clot is suspected. No prior preparation is required for this test.
X-rays (radiographs) are the most common and widely available diagnostic imaging technique. Even if you just complain about a sprain in your wrist or ankle, your doctor will probably order radiographs to make sure no bone is broken. X-rays are always used for fractures and joint dislocations, and may also be recommended if your doctor suspects damage to a bone or joint from other conditions such as arthritis or osteonecrosis (bone cell death). The part of your body being pictured is positioned between the X-ray machine and photographic film. As you hold still, the machine briefly sends electromagnetic waves (radiation) through your body. This exposes the film, creating a picture of your internal structure. The level of radiation exposure from X-rays is minimal, but your doctor will take special precautions if you are pregnant. Bones, tumors and other dense matter appear white or light because they absorb the radiation. Soft tissues and breaks in bone let radiation pass through, making these parts look darker. Sometimes, to make certain organs stand out in the picture, you are asked to drink barium sulfate or be injected with a dye. Several X-rays from different angles may be needed. If you have a fracture in one limb, your doctor may want a comparison X-ray of your uninjured limb. Your X-ray session will probably take 10 to 15 minutes; no specific preparations are required.