Common Tests

X-ray :: MRI :: CT Scan :: Ultrasound :: Myelogram
Arthroscopy :: Bone Scan :: DEXA BMD :: EMG

Your physician may order few tests to diagnose your problem. These inlcude

X-rays

X-raysX-rays are waves of electromagnetic energy. They behave in much the same way as light rays, but at much shorter wavelengths. When directed at a target, X-rays can often pass through the substance uninterrupted, especially when it is of low density.

Higher density targets (like the human body) will reflect or absorb the X-rays. They do this because there is less space between the atoms for the short waves to pass through. X-rays are one of the most common radiology procedures. X-rays produce a still picture of bones and organs.

Since Rontgen’s discovery that X-rays can identify bone structures, X-rays have been developed for their use in medical imaging. Radiology is a specialized field of medicine that employs radiography and other techniques for diagnostic imaging. X-rays are especially useful in the detection of pathology of the skeletal system, but are also useful for detecting some disease processes in soft tissue.

Diagnostic imaging techniques help narrow the causes of an injury or illness and ensure that the diagnosis is accurate. These techniques include X-rays, computed tomography (CT) scans, and magnetic resonance imaging (MRI).

These imaging tools let your doctor see inside your body to get a picture of your bones, organs, muscles, tendons, nerves, and cartilage. Your doctor uses these tools to determine if there are any abnormalities.

X-rays (radiographs) are the most common and widely available diagnostic imaging technique. Even if you also need more sophisticated tests, you will probably get an X-ray first.

The X-ray or radiograph is produced by the transmission of energy. A beam of high-energy photons is passed through the body, some of which are attenuated or blocked when they strike subatomic particles.

The higher the atomic weight of the substance through which the photons are passing, the “denser” it appears to photons, and the more likely they are to be blocked, or attenuated. In decreasing order of density, the principal densities visible in a radiograph are metal, bone, water (including soft tissues such as muscle), fat, and air.

Risks of X-Ray

There is very little risk with having one X-ray test. However, with repeated tests there is a risk that the X-rays may damage some cells in the body, possibly leading to cancer in the future. The dose of X-ray radiation is always kept to the minimum needed to get a good picture of the particular body part being checked.

Also, radiographers who take the X-ray pictures always wear lead aprons or go behind a protective screen when the X-rays are fired to avoid repeated exposure to X-rays.

Pregnant women, if possible, should not have an X-ray test as there is a small risk that X-rays may cause an abnormality to the unborn child. This is why women are asked before having an X-ray if they are, or might be, pregnant.

 

MRI

MRIMRI Stands for Magnetic Resonance Imaging. MRI is a way of getting pictures of various parts of your body without the use of X-rays. Unlike X-rays and computed tomographic (CT) scans, which use radiation, a MRI uses powerful magnets and radio waves. A radio wave antenna is used to send signals to the body and then receive signals back.

These returning signals are converted into pictures by a computer attached to the scanner. Pictures of almost any part of your body can be obtained at almost any particular angle.

MRI is quite safe in the majority of patients. Certain patients may not be able to have an MRI. These include people who get nervous in small spaces (claustrophobic) and those with implanted medical devices such as aneurysm clips in the brain, heart pacemakers and cochlear (inner ear) implants.

Also, people with pieces of metal close to or in an important organ (such as the eye) may not be scanned. There are a few additional safety considerations and some exceptions based on individual circumstances.

This test may be used to diagnose or evaluate:

  • Abnormal growths and tumors
  • Blood flow
  • Blood vessels
  • Lymph nodes
  • Organ function

Combining MRIs with other imaging methods can often help the doctor make a more definitive diagnosis. MRI images taken after a special dye (contrast) is delivered into the body may provide additional information about the blood vessels. An abdominal MRI provides detailed pictures of the belly area from many different views.

It is often used to clarify findings from previous X-rays or CT scans. A pad is placed on the patient’s abdomen to help make the pictures clearer. MRI can distinguish tumors from normal tissues and can help the doctor determine the tumor’s size, severity, and spread. This is called staging.

Advantages & Dis-Advantages

Advantages of MRI include diagnosing:

  • Strokes in their earliest stages
  • Brain and pituitary tumors
  • Spine, or joint infections
  • Visualizing torn ligaments in the wrist, knee, and ankle
  • Visualizing shoulder injuries
  • Herniated discs in the spine

MRI also has disadvantages. These include:

  • People with pacemakers cannot have MRIs
  • Patients who are morbidly obese may not fit into an MRI system
  • Claustrophobic patients often cannot make it through a MRI. These patients may require sedatives or an Open MRI which is an MRI system that is not completely closed around the patient
  • The MRI machine makes a tremendous amount of noise during a scan. The noise sounds like a continual, rapid hammering. The noise is due to the rising electrical current in the wires of the gradient magnets being opposed by the main magnetic field. The stronger the main field, the louder the gradient noise. Patients are given earplugs or stereo headphones to muffle the noise
  • MRI scans require patients to hold still for extended periods of time. MRI exams can range in length from 20 minutes to 90 minutes or more
  • MRI systems are very expensive. Therefore the exams are also very expensive
  • Lastly, people with kidney disease, dialysis patients, or people who didn’t know they had kidney disease are at high risk to develop an incurable condition called Nephrogenic Systemic Fibrosis (NSF) from the MRI dye injection gadolinium. NSF causes a hardening or stiffening of the skin and joints

Preparation for MRI Test

Before your MRI test, tell your health professional and the MRI technologist if you:

  • Are allergic to any medicines
  • If you are or might be pregnant
  • If you wear any jewellery, eyeglasses, hearing aids, hairpins, removable dental work or other objects that may interfere with the procedure
  • Have any other health conditions, such as kidney problems that may prevent you from having an MRI using contrast material
  • Had recent surgery on a blood vessel. In some cases you may not be able to have the MRI test
  • Wear any medication patches. The MRI may cause a burn at the patch site
  • For an MRI of the abdomen, you may be asked not to eat or drink for several hours before the test

 

CT Scan

CT ScanA Computerized Tomography (CT) scanner is a special kind of X-ray machine. The CT scanner was discovered by Sir Godfrey Hounsfield and Dr. Alan Cormack.

A CT Scanner sends several beams of X-Rays simultaneously from different angles to make detailed study of all parts of the body.

Working of A CT scanner

A CT Scanner uses a series of X-ray beams to build up images of the body in slices. The CT scanner emits a succession of narrow beams of radiation as it moves through an arc. The X-ray detector within a CT scanner can see hundreds of different levels of density within the organs of the body including the tissues.

A computer uses this information to work out the relative density of the tissues examined and finally processes the results displaying them as a two dimensional picture on a monitor.

CT-Scan in Medical Treatments

CT Scans are far more detailed than ordinary X-Rays. The CT scanner is particularly good at testing for bleeding in the brain, for aneurysms, brain tumors and brain damage.

A CT Scan can study all parts of the body, such as the chest, abdomen, pelvis, or an arm or leg. It can also study blood vessels, bones and the spinal cord.

Fluoroscopy CT is a special test which allows the doctor to inspect the inside of the body without having to operate or perform unpleasant examinations.

Diagnostic Uses

CT Scans are mainly used to study the different areas of the body. A CT Scan of the chest (thorax) can identify problems within the lungs, heart, esophagus, and the blood vessels or tissues in the chest. The common chest problems that CT Scans identify are lung cancer, pulmonary embolisms, and aneurysms.

A CT Scan of the abdomen can find cysts, abscesses, infection, tumors, bleeding in the abdomen, enlarged lymph nodes, appendicitis, as well as other abnormalities.

A CT Scan of the liver can find liver tumors, bleeding from the liver and liver diseases. A CT Scan of the liver can also help determine the cause of Jaundice.

A CT Scan of the kidneys can find kidney stones, bladder stones or blockage of the urinary tract.

A CT scan can look for problems of the arms or legs, including the shoulder, elbow, wrist, hand, hip, knee, ankle, or foot.

A CT scan can look for problems within the organs of the pelvis. For a woman, these include the uterus, ovaries, and fallopian tubes. For a man, the pelvic organs include the prostate gland and the seminal vesicles.

Transmission Imaging

X-rays, Computer Tomography Scans (CT Scans) and fluoroscopy are radiological examinations whose images are produced by transmission.

A CT scan is a diagnostic imaging procedure that uses a combination of X-rays and computer technology to produce cross-sectional images both horizontally and vertically of the body. A CT scan shows detailed images of any part of the body, including the bones, muscles, fat, and organs.

Preparing a Patient for a CT scan

A CT Scan is usually done by a radiology technologist. The scan may need a contrast dye or substance that improves the picture of certain tissues or blood vessels. This material may be swallowed, given as an enema or injected into the blood stream, depending on the part of your body that is to be scanned.

If the patient is undergoing an abdominal scan, they will be asked not to eat for six hours before the test. The patient will be asked to remove any jewelry or metal fastenings that are in the area to be scanned.

During the scan the patient lies on a bed that is attached to the CT scanner, which is a large doughnut-shaped machine. The CT scanner sends X-rays through the patient’s body and the bed moves slowly backwards and forwards to allow the scanner to take pictures of the body. The length of the scan depends on the number of pictures taken at different angles.

Risks

Doctors do not generally recommend CT Scans without a good medical reason as there is far more X-ray exposure than is involved in ordinary X-rays. Pregnant women should not have a CT scan as there is a small risk that X-rays may cause abnormality to the unborn child.

Nursing mothers should wait for 24 hours after a scan using a contrast dye before resuming breastfeeding.

The contrast dye used in CT Scans often contains iodine, which can cause allergic reaction in some patients.

Also, the dye may cause some kidney damage to people who already have kidney problems.

 

Ultrasound

UltrasoundUltrasound is an imaging technique that uses high frequency sound waves to create images of organs and systems within the body. Ultrasound is non- invasive technique used to diagnose a disease or a condition and also may aid in treatment of diseases.

Ultrasonography is a technical term for ultrasound imaging.

The test is performed in the radiology department. You will probably be asked to lie down on table for the procedure. A clear water based conducting gel is applied onto the patients skin to help with the transmission of sound waves. A transducer or probe is being moved over the area being examined. The scan usually takes about 15 minutes. Ultrasound images are viewed on the screen attached to the scanner.

Ultrasound can be used for various purposes including:

    • Obstetric uses – confirmation of viable pregnancy, detection of developmental or structural abnormalities in the fetus
    • Non-obstetric uses – diagnosis of gallbladder disease or obstruction, evaluation of blood flow in blood vessels, assessment of thyroid gland
    • Echocardiography – specialized type of ultrasound used to look at the action and function of the heart. It is used to detect structural and functional abnormalities of the heart wall, valves, and large blood vessels
    • Doppler echocardiography – it is a recently developed ultrasound technique that indirectly measures the flow velocity of blood as it passes through the heart
    • Ultrasound may also be used to guide a needle into a cavity that needs to be drained or a mass that needs to be biopsied

Patients are requested to avoid eating and drinking 6 to 8 hours prior to examination, if internal organs such as gall bladder are to be examined.

For examination of baby and womb during pregnancy, the patient is recommended to drink at least four to six glasses of water 1 to 2 hours prior to examination for the purpose of filling the bladder

 

Myelogram

MyelogramA Myelogram (Myelography) is an imaging examination performed by a radiologist to detect abnormalities of the spine, spinal cord, or surrounding structures using a real time form of X-ray called fluoroscopy.

Contrast material is injected into the subarachnoid space of the spinal area enabling the radiologist to view and evaluate the status of the spinal cord, nerve roots, and intervertebral discs. Myelography provides a very detailed picture of the spinal cord and spinal column.

How does the procedure work?

X-rays are a form of radiation like radio waves. X-ray machines produce a small burst of radiation that passes through the body, recording an image on photographic film or a special digital image recording plate.

Fluoroscopy uses a continuous X-ray beam to create a sequence of images that are projected onto a fluorescent screen, or television-like monitor. This special X-ray technique makes it possible for the physician to view internal organs in motion.

Diagnostic Use Of Myelogram

Myelography is most commonly used to detect abnormalities of the spinal cord, the spinal canal, the spinal nerve roots and the blood vessels that supply the spinal cord.

A myelogram is performed to assess:

  • The cause of arm or leg numbness, weakness, or pain
  • A tumor or infection causing problems with the spinal cord or nerve roots
  • Narrowing of the spinal canal
  • Inflammation of the arachnoid membrane that covers the brain and spinal cord.

A myelogram may help to find the cause of pain that cannot be found by other tests, such as an MRI or a CT scan.

Procedure

Myelography is done on an outpatient basis. The patient is asked to lie face down on the examination table. The radiologist then uses the fluoroscope to project a sequence of radiographic images on a monitor. This enables the radiologist to visualize the spine to determine where to inject the contrast material.

The contrast material usually is injected into the lower lumbar spine, because it is considered easier and safer. At the site of the injection, the skin will be cleaned and numbed with a local anesthetic.

Depending on the location of the puncture, the patient will be positioned on their side, on their abdomen, or in a sitting position as the needle is inserted.

The contrast material is then injected and the x-ray table is slowly tilted so that contrast material will run up and down the spine and surround the nerve roots that are next to the spinal cord.

The radiologist will monitor the flow of contrast with fluoroscopy, focusing on the area of the patient’s symptoms.

Risks

This procedure is very safe, however, as with most procedures; there are possible risks and complications.

Because X-rays are used during this procedure, pregnant women should not have this test as there is a small risk that X-rays may cause an abnormality to the unborn child.

A small percentage of people who have a myelogram may experience headache, nausea, or vomiting after the test.

There is a small risk of infection at the injection site and a possible risk of bleeding into the spinal canal.

The contrast dye used often contains iodine, which can cause allergic reaction in some patients. Also, the contrast dye may cause kidney damage in people who have a history of kidney problems.

 

Arthroscopy

ArthroscopyArthroscopy is a surgical procedure in which an arthroscope is used for diagnosis and treatment of orthopaedic conditions.

Arthroscopic technique is used to evaluate and diagnose a joint problem, and perform surgery to repair the joint. An arthroscope enables the surgeons to view the damaged joint and surrounding soft tissues. During arthroscopy, the arthroscope is injected into the joint through a small incision around the site of injury. It has a light source and an attached video camera that enables your doctor to view larger images on a video monitor.

Arthroscopy offers several benefits including smaller incisions, minimal pain, faster healing and less scarring. The procedure can be done on an outpatient basis without an overnight stay in the hospital.

Some of the most frequent conditions found during arthroscopic examinations of joints are:

  • Inflammation of the synovial membrane (membrane lining the joints of the knee, shoulder, elbow, wrist, or ankle)
  • Acute or chronic injury: Injuries to the joints of the shoulder, knee and wrist such as cartilage tears, tendon tears, carpal tunnel syndrome
  • Osteoarthritis: A type of arthritis caused by cartilage loss in a joint
  • Removal of loose bodies of bone or cartilage that becomes logged within the joint

During an arthroscopic surgery, you will be administered general, spinal or local anesthesia. A small buttonhole sized incision is made through which the arthroscope is inserted. Other specially designed instruments will be inserted through other small incisions. After the procedure the arthroscope is removed and incisions are closed. You may be instructed regarding incision care, activities to be avoided and exercises to be performed for faster recovery.

Some of the possible complications after arthroscopy include infection, phlebitis (clotting of blood in vein), excessive swelling, bleeding, blood vessel or nerve damage and instrument breakage.

Recovery

It may take several weeks for the punctured wounds to heal and the joint to recover completely. A rehabilitation program may be advised for a speedy recovery of normal joint function. You can resume normal activities within few days.

 

Bone Scan

Bone ScanA bone scan is an imaging test that detects areas of increased or decreased bone metabolism. Bone Scans assist in identifying tumors, infection, or fractures. The radiopharmaceutical most commonly used is 99mTc-Medronate (MDP). MDP is injected into a vein, usually in the arm, where it is transported by the bloodstream to the bones.

Indications

A bone scan is used to identify abnormalities involving the bone. Some abnormalities that can be assessed include:

  • Arthritis
  • Bone tumors
  • Fractures
  • Bone Infection (osteomyelitis)
  • Degenerative disorders
  • Metabolic disorders
  • Cancer

Results of the Scan

Bone Scan results include the following descriptions:

  • Normal distribution:
    Areas where the radioactive substance has been distributed normally will appear uniform and gray throughout all the bones in the body.
  • Hot spots:
    Areas where there is increased accumulation of the radioactive substance appear black on the scan. Hot spots may be caused by a fracture, bone cancer, infection, arthritis or other diseases such as Paget’s disease.
  • Cold spots:
    Areas where there is a lack of radioactive substance appear light or white on the scan. Cold spots may be caused by a certain type of cancer such as multiple myeloma, or lack of blood supply to the bone.

Pre-procedural preparation

  • You will be asked to remove all jewelry and other metal objects. You may be asked to wear a hospital gown.
  • Women who are pregnant or think they could be pregnant should inform their physicians of their condition prior to the test due to the potentially adverse effects of radiation exposure to the unborn child.
  • Drinking plenty of fluids before and after the injection of the MDP often helps to give better pictures of your bones.
  • You will be instructed to urinate prior to the exam to ensure that the radioactive substance is not concentrated in the bladder.

Procedure

A bone scan involves injecting a radioactive material called a radiotracer into a vein. The radiotracer travels through the bloodstream and collects in the bones of the body. As the radiotracer wears off it gives off radiation. This radiation is detected by a camera that slowly scans your body. The camera takes pictures of how much radiotracer collects in the bones.

If a bone scan is done to see if you have a bone infection, images will be taken shortly after the radioactive material is injected and again 3 to 4 hours later, when it has collected in the bones. This is called a 3-phase bone scan.

To evaluate metastatic bone disease, images are taken only after the 3 to 4 hour delay. Normal bone areas will appear gray.

“Hot spots” are areas where there is an increased absorption of the tracer. These areas will appear dark. “Cold spots” are areas where there is less absorption of the tracer. These areas will appear light on the scan. The scanning part of the test will last about 1 hour and may require you to change positions.

How safe is a Bone Scan?

If the patient is pregnant or nursing a baby, the test will probably be postponed to decrease the chance of radiation exposure affecting the baby.

The amount of radiation injected into your vein is very small, and nearly all radiation is gone from the body within 2-3 days.

Risks related to the bone radiotracer are rare, but may include:

  • Anaphylaxis (severe allergic response)
  • Rash
  • Swelling

There is a slight risk of infection or bleeding when the needle is inserted into a vein.

 

DEXA BMD

DEXA BMDBone Mineral Density test is a procedure that allows a doctor to determine the bone health using special X-Ray, CT-Scan or Ultrasound tests. Bone Mineral Test measures the density of minerals such as calcium that are present in the bone. This test can identify osteoporosis, a disease that causes bones to become more fragile and likely to break.

Bone Mineral Density Test is also called a dual-energy X-ray abnormality or DEXA test. A bone density test uses X-rays to measure how many grams of calcium and other bone minerals are packed into a segment of bone. The results of a bone density measurement are reported in two ways: as T-scores and as Z-scores.

A T-score compares the bone density to the optimal peak bone density for gender. A T-score of greater than minus 1 (-1) is considered normal. A T-score of minus 1 to minus 2.5 is considered osteopenia, and is a risk for developing osteoporosis. A Z-score is used to compare your results to others of same age, weight, ethnicity, and gender. A Z-score of less than minus-1.5 raises concern of factors other than aging as contributing to osteoporosis.

Indications

A bone mineral density test informs your doctor about the mineral content in your bones and helps diagnose Osteoporosis. The higher the bone mineral content, the denser the bones are. And the denser the bones, the stronger they generally are and are therefore less likely to break.

Procedure

A bone mineral density scan is usuallydone in the special radiologydepartment or clinic by a technologist.There are different machines that cando bone mineral density testing. Themost common methods use low-doseX-rays (1/10th the radiation dose of achest X-ray).

The patient will lie on a padded table. A scanner passes over the patient’s body and the machine takes X-rays of the lower spine and hip. The machine will scan the bones and measure the amount of radiation they absorb. Testing at least two different bones each time, usually the hip and spine, is the most reliable way of measuring BMD. It is best to test the same bones and to use the same measurement technique and BMD equipment each time.

Peripheral dual-energy X-ray absorptiometry (P-DEXA) machines are portable units that can be used in a doctor’s office. P-DEXA can measure bone density in the wrist or forearm. Ultrasound measurements are usually taken in the heel. For these measurements, the patient may be able to sit in a chair during the test.

Risks

Bone density tests are easy, fast and painless. In fact, some simple versions of the bone density tests can be done at a local pharmacy or drugstore. Possible risks of a Bone Mineral Density Test include:

  • During a bone mineral density scan, the patient is exposed to a very low dose of radiation
  • A BMD scan is not recommended for pregnant women because of the radiation exposure to the unborn baby

 

EMG

EMGAn EMG is designed to record the electrical activity produced by the muscles, during rest and contraction.Your doctor may arrive at a diagnosis based on the results of the EMG along with information from your medical history, physical and neurological examinations, and results from other tests.

Indications

EMG testing can be used for the diagnosis of a variety of disorders that damage muscle tissue, nerves, or the junctions between nerve and muscles. An EMG can also be used to evaluate the cause of weakness, paralysis, and muscle twitching.

Prior to the procedure

You will be instructed not to use lotion on your skin prior to the procedure. Please take all your usual medications on the day of the procedure.

Procedure

Electromyography is performed by an EMG technologist or a doctor. It may be conducted in a doctor’s office, hospital or clinic. During the test, you will be asked to lie down on a table or bed so that the muscles being tested are relaxed.

An EMG normally takes about 20 to 40 minutes. A needle electrode is inserted into the muscle, connected by wires to a recording machine. You may feel a quick, sharp pain during the insertion of the electrode. The doctor then records your readings with the muscle at rest and under contraction. The needle electrode may be moved several times to record the electrical activity in different areas of the muscle. On the computer screen the electrical activity may be depicted as wavy and spiky lines. Electrical impulses may also be monitored through a speaker, in which the electrical signals are denoted by a popping sound or monitored on video. After the test, the needle electrode is removed.

Some soreness and a tingling sensation may persist for 1 or 2 hours after electromyography.Certain factors or conditions may interfere with the test results. These tests are usually avoided in individuals with swelling, bleeding, or obesity.

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