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Our fluoroscopy equipment combines traditional fluoroscopic examinations such as barium meals and barium enemas, with more specialised procedures such as micturating cystourethrograms (MCU) in infants and hysterosalpingograms. Automatic exposure systems allow fluoroscopic procedures to be performed more rapidly and more accurately than with traditional equipment. Patient comfort is improved and the need for repeat examinations eliminated.
Contrast Agents
A limitation of plain xray examination is that most of the soft tissue structures of the body are of similar radiographic density. In order to visualise these various soft tissue structures, contrast agents were developed and improved during the 20th century. We now have the means to demonstrate most of the structures in the body using contrast agents with xray techniques.
The two most frequently used contrast agents are barium sulphate and water soluble agents such as iopamidol.
Barium Sulphate
Barium sulphate is an inert substance which can be ingested into the bowel and used to outline the various portions of the gastrointestional tract. Barium is not absorbed into the bloodstream and is completely harmless. Examples of barium studies are:
Barium swallow: This is used for the investigation of problems such as swallowing disorders. Video recordings are made as the barium is swallowed.
Barium meal: Used for examination of the oesophagus, stomach and duodenum.
Small bowel study: Used to examine the structure and motility of the small bowel.
Barium enema: Barium and air are introduced through a tube in the rectum to outline the large bowel.
Water Soluble Contrast Agents
Water soluble contrast agents can be safely injected into the bloodstream, either arteries or veins. This can allow images of the arteries or the veins to be obtained, or it can be used to enhance various organs or structures. It can also be injected into various other parts of the body.
Intravenous contrast examinations
Venography: Contrast medium injected into a vein in the foot can check for venous thrombosis in the leg (although ultrasound techniques have now largely replaced venography).
Intravenous Urography (IVU): Contrast medium injected intravenously is excreted rapidly by the kidneys. Xrays exposed at intervals following intravenous injection will display the kidneys, the ureters and the bladder.
Computed Tomographic Scanning (CT): Intravenous contrast medium is frequently used to enhance the body structures shown on CT.
The safety of Intravascular Contrast Agents
If any substance is injected into the body there is some risk of an adverse reaction to that substance. Prior to the 1980's it was not uncommon for people to experience side effects such as nausea, or to have allergic reactions of varying severity, following intravascular injection of contrast agents. Major advances in pharmacology led to the development of nonionic contrast agents. Side effects and allergic reactions to these agents are rare. When these do occur they are usually mild and of no concern. More severe reactions may occur but fortunately these occurrences are very rare.
Allergic reactions are difficult to predict but if you;
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have a history of a previous reaction to contrast media, |
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have a strong allergic history, |
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are an asthmatic, |
you should tell the radiologist before the procedure. Preventative measures may need to be taken in these circumstances.
Intra-arterial contrast examinations
Arteriography: Arteriograms, or angiograms, can demonstrate problems such as narrowing of the arteries to the brain, the legs or the heart (a coronary angiogram). With the exception of coronary angiograms, many arteriogram examinations are being replaced by Magnetic Resonance (MR) procedures.
Other investigations using injected contrast agents
Other procedures where contrast agents are injected for xray examinations include:
Arthrography: Contrast medium is injected into joints to allow visualisation of cartilages, ligaments and other structures.
Cystography: Contrast medium is instilled into the bladder. Micturating cystourethography (MCU) is used in children to check for potentially damaging reflux of urine from the bladder to the kidneys.
Sialography: Contrast examination of the salivary glands.
Dacryocystography: Contrast examination of the tear ducts.
Hysterosalpingography: Contrast examination of the uterus and fallopian tubes. |
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