|
|
|
|
| | |
|
 | |
| Radiology |
The Department of Radiology at university hospital-Sharjah offers a wide variety of diagnostic radiology examinations for both
inpatients and outpatients. All imaging procedures are performed using state-of-the-art equipment that is subject to
stringent regulatory standards. Our team specialized radiologists and expert technologists provides the best service
possible with the latest advances available within the field.Radiologic examinations offer safe and noninvasive methods of
gaining information for improved diagnosis and treatment.
Frequently asked questions include:
Am I receiving too much radiation?
Does it hurt?
How long does it take?
Dose it needs to be fasting?
We wish to answer most of your questions about medical imaging and in alleviating some of the unknowns you may have.
Please feel free at all times to discuss any additional questions or concerns with our team.
Computed Tomography (CT)
Computed tomography (CT), also known as Computed Axial Tomography (CAT), is a painless, sophisticated x-ray procedure.
Multiple images are taken during a CT or CAT scan, and a computer compiles them into complete, cross-sectional pictures
("slices") of soft tissue, bone, and blood vessels. A CT scan obtains images of parts of the body that cannot be seen on a standard x-ray.
Therefore, these scans often result in earlier diagnosis and more successful treatment of many diseases.
A CT scan is considered to be a safe examination. While CT imaging does involve x-rays, the diagnostic benefits generally
outweigh the risks of x-ray (radiation) exposure. CT uses a computer and a rotating x-ray device to create detailed,
cross-sectional images, or slices, of organs and body parts.
CT scanning has the unique ability to image a combination
of soft tissue, bone, and blood vessels. Among all available imaging techniques, it is one of the best tools for studying the lungs and abdomen.
It is also invaluable in cancer diagnosis, and is the preferred method for diagnosing lung, liver, and pancreatic cancer.
For many CT examinations, a contrast agent will be administered. Depending on the type of examination, the contrast may be given orally,
intravenously, or as an enema. If certain types of contrast will be used during an examination, the patient may be required to fast for
several hours or use an enema to cleanse the colon prior to the appointment.
Magnetic Resonance Imaging (MRI)
An equally impressive technology, magnetic resonance imaging or MRI, has greatly improved the sensitivity and specificity of diagnostic imaging, particularly in structures such as the liver, brain, spinal cord, and joint spaces.
A great advantage of MRI is that the patient is not exposed to x-rays. The images are created with the use of strong magnetic fields, radiofrequency transducers (called coils), and computer assisted image processing. To date, no any side effects have been reported by use of superconducting magnets or radiofrequency pulses in the diagnostic range.
Solutions such as gadolinium are sometimes injected intravenously into an arm vein, as contrast agents to enhance lesions. Few adverse drug events are reported with these agents.
Prior to the MR examination, patients are asked to fill out a screening questionnaire to identify any indwelling magnetic materials (metal fragments, shunt regulators, cardiac pacemaker, or other devices) that may not be safely placed in the magnetic field. Many devices, despite containing metal, can be safely imaged.
During the examination, which takes an average of thirty minutes, a "knocking" sound can be heard. This is a normal effect of the gradient coils responding to the different fields. Despite this noise, most patients can easily tolerate the procedure. As with the CT scan, a technologist is always in close observation and intercom communication with the patient throughout the procedure.
Ultrasound
In many instances, a quick and painless exam can be performed without ionizing radiation.
The exam is called a sonogram, or ultrasound scan. Ultrasound is defined as sound with a frequency greater than 20,000
cycles/sec (Hertz, or Hz), which is the upper limit of audible sound. Sonography for diagnostic imaging purposes employs
frequencies of one million to twenty million cycles per second.
These are produced by a device known as a transducer, which is placed directly on, and occasionally within, the patient.
The device contains a material that vibrates upon receiving a voltage charge. Sound waves are then created and either transmitted,
refracted, or reflected back to a receiver. The degree of reflection is based on applied frequency, the sound velocity,
and the acoustic impedance of the tissue. In other words, different tissues will have different responses to the sound waves.
Various transducers have been optimized for specific body parts. Major applications of ultrasound include obstetrical imaging,
abdominal imaging, and Doppler imaging, a variant technique used in heart and vascular diagnosis. In some instances, biopsies are performed under the guidance of ultrasound, permitting more accurate and less invasive tissue sampling.
Bone Densitometry (BMD) or (DEXA Scan)
DEXA stands for "dual-energy x-ray absorptiometry," and BMD stands for Bone Mineral Density DEXA is considered the most accurate
test for bone density. While standard x-rays show changes in bone density after about 40% of bone loss, a DEXA scan can detect
changes after about a 1% change.
DEXA uses a small amount of radiation. However, the amount of radiation used in a DEXA scan is very low,
less than the amount of radiation you get in one day just living on Earth.
Osteoporosis is a common bone disease that causes bone to become weak. This weakness can lead to fractures of the spine, hip, ankle, and wrist from simple falls which might not have resulted in a fracture in someone with normal bones.
The World Health Organization is the source of the commonly accepted definitions for osteoporosis (WHO Technical Report Series #843, Geneva 1994):
Normal: A value for BMD statistically within 1 standard deviation of the young adult peak bone mass.
The report shows a T score between +1 and -1, signifying a BMD within the normal range.
Low bone mass (medically termed Osteopenia): A value for BMD greater than 1 standard deviation but less than 2.5 standard
deviations below that of an average young adult. The report shows a T score between -1 and -2.5, which signifies an increased fracture
risk but does not meet the criteria for osteoporosis.
Osteoporosis: A value for BMD 2.5 or greater standard deviations below that of the average peak young adult bone mass. BMD in this range signifies an even higher fracture risk than osteopenia. The report shows a T score of -2.5 or lower.
Mammography
Mammography, a plain x-ray technique, is designed for breast examinations. The breast is placed on x-ray plate and gently pressed.
The compression, although uncomfortable, greatly improves the visibility of abnormalities. Mammography, as a screening tool,
has been found to save many lives. Mammography plays a central part in early detection of breast cancers because it can show changes
in the breast up to two years before a patient or physician can feel them.
Digital mammography is a new type of breast cancer screening.
It is done the same way as a regular mammogram. But instead of storing the images on film, a digital mammogram records
and stores the images on a computer. Digital mammography may be better than film mammography at finding cancer in women younger
than 50 and women with dense breast tissue
Aniography
Angiographic and interventional radiologic techniques are also performed with injection of contrast material. In this instance,
catheter insertion or needle placement is performed under fluoroscopic guidance, so that a particular vessel or organ can be seen
and, in some instances, repaired via the catheter.
A classic example is angioplasty, for which a catheter is threaded into an obstructed vessel. An attached balloon is inflated
to increase the opening of the vessel-thus improving blood supply to the tissues. This procedure is commonly performed on vessels
in the heart, abdomen, and legs. As one might expect, these interventional techniques are complex procedures, involving teams of
nurses, doctors, and radiographers working together.
The great advantage is that angioplasty and other image-guided interventional procedures replace the need and risks of surgery and
general anesthesia for many patients. The interventional service offers more specific information and advice for patients undergoing
these procedures.
Flouroscopy
Contrast Radiography
A major improvement to the diagnostic accuracy of radiography has been the addition of contrast agents, which can be administered in a vein
or instilled in a duct or hollow organ, such as barium sulfate in the alimentary tract.
A contrast medium contains relatively dense material of a high atomic number that absorbs more of the x-rays than the surrounding tissues,
hence making the stomach, colon, or vessel appear white on the x-ray film. One can then look for structural changes such as polyps, stones,
or ulcerations.
Upper Gastrointestinal Series (UGI)
An upper gastrointestinal (UGI) series looks at the upper and middle sections of the gastrointestinal tract .
The test uses barium contrast material, fluoroscopy, and X-ray. Before the test, you drink a mix of barium
(barium contrast material) and water. The barium is often combined with gas-making crystals.
Your doctor watches the movement of the barium through your esophagus, stomach, and the first part of the small intestine
(duodenum ) on a video screen. Several X-ray pictures are taken at different times and from different views.
Barium is a dry, white, chalky, metallic powder that is mixed with water to make a thick milkshake-like drink. Barium
is an x-ray absorber and appears white on x-ray film. When swallowed, a barium drink coats the inside walls
of the upper GI tract organs so that the swallowing motion, inside wall lining, function, size, and shape of these
organs are visible on x-ray. This process shows differences that might not be seen on standard x-rays. Barium is
used only for diagnostic studies of the GI tract.
The exam will take approximately half an hour. Additional films of the barium moving through the small intestine
may be taken when requested by the referring physician. This can add anywhere from 45 minutes to several hours.
Throughout these procedures, the patient usually feels no discomfort or pain.
Barium Enema
The lower GI tract, including the colon and rectum, are also important areas to examine.
The x-ray procedure for that area is called the barium enema.
In addition to not eating breakfast, a bowel-cleansing preparation must be administered the day before the procedure to permit
clearer images of the large bowel and surrounding tissues.
At the time of examination, a barium mixture is instilled through an enema tip placed in the rectum by the radiologist.
This procedure may cause some discomfort but is not painful. As it is instilled, the radiologist will examine and film the flow of barium. S
ometimes, air is added to the barium mixture. The patient will be asked to move to several different positions. Patients should try to
relax and hold their breath when instructed in order to avoid blurred images.
When the radiologist has completed his or her portion of the exam, the radiographer will take several more images to demonstrate
various portions of the large bowel. Once the imaging sequence is finished, the technologist will assist the patient to the toilet.
Afterward one or more images will be taken to demonstrate the emptied bowel.
Intravenous Urography
Intravenous Urography used to examine the urinary tract, a contrast medium containing iodine is injected intravenously
(into a vein, usually in the arm). The iodine improves the contrast on the x-ray image. Some people are allergic to iodine
and must be premedicated. Prior to the procedure, all patients should be sure to fill out the contrast screening form and to
notify the radiographer of any prior reaction.Intravenous Urography (IVU) and Pyelography (IVP) are different names for x-ray
examination of the kidneys, ureters, and bladder. This test yields information about the function of the kidneys, the presence
of stones in the urinary tract, and the passage of urine from the kidneys to ureters and bladder.
IVP is commonly done to identify diseases of the urinary tract, such as kidney stones, tumors, or infection.
It is also used to look for problems with the structure of the urinary tract that were present from birth (congenital).
The test takes approximately one hour. Some patients may experience a brief sensation of warmth, nausea, or a metallic taste
in the mouth after the contrast medium injection. Other patients may experience itching, hives, or other effects.
The radiographer or nurse closely monitors all patients for any adverse drug events.
|
|
|
|
|
