Department of Radiology,
Lister Hospital,
Stevenage,
Herts SG1 4AB

Email: Dr. Amerasekera
Tel: 01438 781 028
Fax: 01438 781 176

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The North Herts Radiology Group

Contrast Study

Contrast Agents

Contrast agents are radio-opaque substances which are introduced into the body by mouth, per rectum or by injection. Some patients are allergic to these contrast agents. if you are allergic to any substances or have asthma or hay fever it is very important that you mention this to the Radiologist who will be performing the examination .

Background

In recent years (1986 to the present), several "nonionic" or "low osmolar" agents have been introduced and widely marketed in the U.S. and UK. These include iohexol (Omnipaque, Winthrop), iopamidol (Isovue, Squibb) and ioversol (Optiray, Mallinckrodt). An additional agent, ioxaglate (Hexabrix, Mallinckrodt) is best described as an ionic, but low osmolar contrast agent. We will subsequently refer to this group of agents interchangeably as either nonionic or low osmolar, unless specified otherwise. The cardiovascular effects of the newer low osmolar agents have been thoroughly investigated during premarketing surveillance and subsequent clinical use (7-14). These data suggest that the low osmolar agents are better tolerated than the high osmolar agents and are possibly safer in hemodynamically compromised patients, but that the low osmolar agents are much more expensive.

The low osmolar agents cost approximately 10 times more than conventional ionic agents. Despite the high cost, use of these agents is increasing. In our practice we do not use ionic agents intravenously . Controversy exists over whether the possible safety benefits of low osmolar agents outweigh their substantial increase in costs.

Administration of high osmolar contrast agents produces a systemic arterial vasodilation. This phenomenon results in characteristic flushing or sensation of warmth experienced by the patient. These effects are dose dependent. This sensation is clearly reduced by low osmolar agents.

Renal Toxicity

Administration of iodinated contrast medium may produce acute renal insufficiency. This is frequently manifested as an alteration in the laboratory measures of renal function, but less commonly requires treatment with dialysis or results in permanent injury. A number of risk factors have been identified in predicting this complication including diabetes mellitus, multiple myeloma and volume depletion.

Allergic Manifestations

Anaphylactoid reactions occur in 1% to 2% of patients undergoing procedures utilizing iodinated contrast media. The incidence of severe reactions is approximately 0.1%.

Morbidity and Mortality

Fatal reactions to contrast media are very uncommon. Several very large scale radiologic studies have compared complications (including mortality) in patients who receive contrast agents, usually intravenously, for procedures such as pyelography or computed tomography. However, these large studies were not randomized and the choice of contrast agent was determined by the radiologist. The low incidence of contrast agent related mortality in general radiography (I in 40,000) has precluded definitive conclusions from the published studies regarding the relative mortality risk of the available agents.

Please note

If you suffer from any allergies, asthma or hayfever please inform the Radiologist. If you have had a reaction to any injections please let us know. Those on tablets (Metformin) for their diabetes ask the Radiologist whether it is safe to proceed with the examination. We take great care to avoid reactions to contrast although reactions are rare. You are most welcome to speak to the Radiologist or the Radiographer if there are any queries. Phone: Lister 01438 781028 or Pinehill 01462-422822 If you are taking treatment for kidney or heart problems please let the Radiologist know and discuss this with your own Physician

The descriptions provided about the different investigations are for general information. The procedure may vary according to the patients clinical problem. Please discuss your queries with the Radiologist.

The Urinary Tract

The urinary tract, or system, consists of the kidneys, ureters, bladder, and urethra. The kidneys are two bean-shaped organs located below the ribs toward the middle of the back. The kidneys remove extra water and wastes from the blood, converting it to urine. They also keep a stable balance of salts and other substances in the blood. The kidneys produce hormones that help build strong bones and help form red blood cells. Narrow tubes called ureters carry urine from the kidneys to the bladder, a triangle-shaped chamber in the lower abdomen. Like a balloon, the bladder's elastic walls stretch and expand to store urine. They flatten together when urine is emptied through the urethra to outside the body.

Renal Stones

Gallstones and kidney stones are not related. They form in different areas of the body. If you have a gallstone, you are not necessarily more likely to develop kidney stones

Appearance of renal stones

Very little of what we eat is retained by the body, most is excreted. Sometimes, portions of the excreted material crystallize into stones of various sorts. Bile can crystallize in the gallbladder and form gallstones. Urine in the kidneys can form kidney stones, which can cause writhing flank pain and bleeding into the urine (hematuria). Kidney stones can enlarge and block the part of the kidney that collects the urine (staghorn calculus), or they may try to travel from the kidney to the bladder through the tube that connects these two organs, the ureter.
While the kidney is a relative capacious space for stones, the ureter is not. It is a tiny muscular tube about the thickness of a shoelace. Having a stone block the ureter is like a tiny rock with sharp edges getting stuck in it. The kidney is still filtering and putting out urine, but it all gets backed up behind that stone, and the battle begins. The pressure of the backed-up urine either pushes the little prickly stone along the ureter, causing severe pain and bleeding as the lining of the ureter gets scraped; or the stone can get stuck in one spot and completely block the flow of urine from the kidney. With time, most stones are eventually pushed all the way through the ureter into the bladder where they pass with the outgoing urine into the outside world. In the meantime, if they're stuck, they may need the help of a urologist

Sometimes stones do not cause symptoms and are found on x-rays taken during a general health screen. These stones are likely to pass unnoticed. More often, kidney stones are found on an x-ray or Ultrasound scan taken on someone who complains of blood in the urine or sudden pain. These diagnostic images give the doctor valuable information about the stone's size and location. Blood and urine tests help detect any abnormal substance that might promote stone formation. The doctor may decide to scan the urinary system using a special x-ray test called an IVP (intravenous pyelogram). The results of all these tests help determine the proper treatment. IVP is the first test that is performed when a stone is suspected in the renal tract.

RENAL CANCER

Renal cell carcinoma is a form of kidney cancer caused when cells in the lining of the renal tubule undergo cancerous changes. It is the most common type of kidney cancer, affecting about 3 out of 10,000 people. It is more common in men than women, usually men over 55 years old. Why the cells become cancerous is not known. A history of smoking greatly increases the risk for developing renal cell carcinoma. There may be a hereditary component involved in the tendency to develop renal cell carcinoma. A history of kidney cancer (in the patient or family) increases the risk. Kidney disorders that require dialysis for treatment also increase the risk for developing renal cell carcinoma. The disorder is diagnosed in most cases on investigation for causes of blood in the urine. It is not uncommon for both kidneys to be involved. The cancer metastasizes (spreads) easily, most often to the lungs and other organs, with about one-third of cases showing metastasis at the time of diagnosis.

BLADDER CANCER

Bladder cancer is the fifth most common neoplasm and the twelfth leading cause of cancer death. Males are affected three times more frequently than women. Numerous chemicals are suspected bladder cancer forming agents, however, only cigarette smoking and occupational exposure to a certain class of organic chemicals called aromatic amines (beta-naphthylamines, xenylamine, 4-nirtobiphenyl, benzidine) are well-established risk factors.2 Bladder cancer due to aromatic amine exposure has been documented in the textile, leather, rubber, dye, paint, hairdressing, and organic chemical industries. A period of 5 to 50 years may follow the exposure of carcinogenic agents and the diagnosis of bladder cancer by a physician . The more one smokes the greater the risk of bladder cancer; in most cases the risk from smoking increases the chance of bladder cancer two- to five-fold. No direct relationship between secondhand smoke inhalation and bladder cancer has been established. The most common clinical presentation is blood in the urine or hematuria. Usually this is painless and the blood may be visible to the naked eye (gross hematuria) or can be seen only under the microscope (microscopic hematuria). Frequently the diagnosis of bladder cancer is delayed because bleeding is intermittent or attributed to other causes such as urinary tract infection or blood thinners. However, a substantial proportion of these patients will have a significant problem such as kidney stones or tumors, urinary tract obstruction and bladder cancer. IVU helps in the diagnosis usuall confirmed by cystoscopy. CT or MRI scan helps in the staging of the tumour.

PROSTATIC CANCER

The prostate gland, located at the base of the penis, surrounds the urethra and produces seminal fluid. Cancer of the prostate is one of the most common cancers among men, with an incidence rate exceeding that for lung cancer. It is primarily a disease of the elderly: The median age at diagnosis is 72. The dramatic increase in prostatic cancer is in part due to the greater frequency of operations for benign disease of the prostate, with the subsequent incidental finding of asymptomatic prostatic tumours, as well as the escalation in the use of new diagnostic technology including transrectal ultrasound guided needle biopsy, computer tomography, and serum testing for prostate-specific antigen (PSA). However, the steady increase in the mortality rates implies that the escalation in incidence is not solely attributable to incidental discovery and early detection, but to a real change in the risk of developing the disease. The evidence for an important role of diet in prostate cancer development has increased over the last decade. Reports of greater sexual activity and frequency of venereal disease in prostate cancer cases than controls raises the possibility that some cases may be the result of a sexually transmitted agent although no likely microorganism has been identified. A history of some benign prostatic disease, including prostatitis and some types of hyperplasia , may increase the risk of prostate cancer. Studies of occupational groups have shown farmers to be consistently at higher risks for prostate cancer, although it is unclear if this finding is the result of occupational factors or to concomitant lifestyle factors. Other studies weakly suggest associations with work in rubber manufacturing, iron and steel foundries. Although the mechanism of prostate cancer development is not understood, hormones, including the male androgenic hormone, testosterone, could play an important role. These hormones are essential in normal prostate development and function; their manipulation is important in prostate cancer treatment and in the development of prostate cancer in experimental animals.

Symptoms:- More specific symptoms of prostatic cancer can be : presence of blood or pus in the urine or sperm; painful ejaculation; pain in the back or hips. The most frequent symptoms are identical to those of benign prostatic hypertrophy . It is for this reason that, if you have these symptoms, you should consult your family doctor. In most cases the cause will be a benign tumour (BPH). Regular check-ups can detect prostatic cancer in its early stage, which increases the likelihood of a cure. Your GP will confirm the diagnosis and answer all your questions on this subject.

Diagnosis of prostatic cancer Doctors have various methods at their disposal for detecting prostatic cancer. Digital rectal examination PSA : Prostate Specific Antigen PSA is an antigen (substance) produced exclusively by the prostate. When raised levels of this antigen are present in the blood, this may be a sign of prostatic cancer. A rise in the level of PSA can indicate a worsening of prostatic cancer. Sonography During this examination, the doctor inserts a small instrument into the rectum. Biopsy The doctor can remove a small part of the prostate for microscopic examination. This enables the presence or absence of cancerous cells to be determined. It is the only way to definitively diagnose prostatic cancer.

Fluoroscopy

One of the first imaging improvements was the fluoroscope. Described by an Italian physicist three months after Roentgen's X ray discovery, it consisted of a tube with a fluorescent screen at one end and an eyepiece at the other. A body part placed between the X-ray tube and the screen produced an image even in a lighted room. A month later, Thomas Edison announced that calcium tungstate would fluoresce brighter than the original barium platinocyanide. Newspaper accounts of the day suggested that "X-ray photographs" would no longer be necessary because of the accurate images produced by the fluoroscope. History proved these predictions wrong. Several radiological investigations like Barium studies and Arteriography involves fluoroscopy. Fluoroscopy involves a small dose of radiation and it is important that you indicate to the Radiologist if you think you may be pregnant Radiologists are specially trained in the use of Fluoroscopy to minimise the risks.Video fluoroscopy is a means of studying the motion of joints of the body or study the movements of the muscles of the throat during swallowing and recording the results of that motion on Video tape.

Buscopan

BUSCOPAN is a drug which relaxes the smooth muscle of the gastrointestinal, biliary and urinary tracts and is commonly given during barium examinations. Buscopan is administered intravenously. The half-life of the terminal elimination phase is approximately 5 hours. The total clearance is 1.2 l/min, approximately half the clearance is renal.

Contraindications

BUSCOPAN is contraindicated in myasthenia gravis, megacolon and in patients who have demonstrated prior sensitivity to the product. In addition, BUSCOPAN should not be administered parenterally in the following disorders: untreated narrow angle glaucoma; tachycardia, hypertrophy of the prostate with urinary retention; and mechanical stenoses of the gastrointestinal tract. Due to the risk of transient visual accommodation disturbances following parenteral administration, patients should not drive or operate machinery until vision has normalised.

Pregnancy and Lactation

Long experience has shown no evidence of ill effects during human pregnancy. However, the usual precautions regarding the use of drugs at this time, especially during the first trimester, should be observed. Safety during lactation has not yet been established, however, adverse effects on the new born have not been reported. Very rarely hypersensitivity reactions, particularly skin reaction and, in extremely rare cases, dyspnoea have been reported. The anticholinergic effect of tricyclic antidepressants, antihistamines, quinidine, amantadine and disopyramide may be intensified by BUSCOPAN. Concomitant treatment with dopamine antagonists such as metoclopramide may result in diminution of the effects of both drugs on the gastrointestinal tract. The tachycardic effects of beta-adrenergic agents may be enhanced by BUSCOPAN.

Barium Swallow and Barium Meal

What is the oesophagus? The oesophagus is a muscular tube approximately 20 cm (8 inches) in length that passes from the neck, behind the major blood vessels and heart in the chest, to penetrate the diaphragm (at the hiatus), and joins the stomach at another muscular valve (lower oesophageal sphincter). Food does not simply fall down through the oesophagus by gravity. The muscle bands of the oesophagus contract sequentially like a snake to propel food actively from top to bottom. The lining of the oesophagus is smooth to facilitate passage of food and fluid; nothing is actually absorbed in the oesophagus. The lower oesophageal sphincter is a muscular ring where the oesophagus joins the stomach, usually just below the diaphragm. It relaxes reflexly as food and fluids pass down through the oesophagus. While fasting, and after eating, the valve stays closed to prevent food and fluid refluxing back up the oesophagus.

What is the stomach?The stomach is a muscular bag, which can distend with large meals, and acts as the reservoir for food. Its movements help churn up the food into a soft thick soup. The stomach lining contains cells which produce acid and other digestive enzymes, which help break down the food.

What happens after the test? A barium meal takes approximately half an hour. Normally, people can resume their daily activities afterwards, although you may want to take it easy for the rest of the day. You can begin eating normally again. Make sure you drink at least three litres of fluid each day for the next few days to flush the barium through your system. Your stools will be light coloured for one to three days. What are the risks? This is a safe test. There are no significant risks.

A barium examination of the esophagus (gullet) is referred to as a Barium swallow. A barium examination of the upper digestive tract (the area from the mouth to the start of the small intestine) is called a barium meal. The patient swallows a cup full of barium (a liquid that enhances X-ray images) and gas granules and stands in front of a fluoroscopy machine.

Small Bowel Meal

The small bowel represents that portion of the digestive tract that lies between the stomach above and the large bowel (colon) below. The small bowel is extremely long (approximately 30 ft) and tortuous, and therefore very difficult to investigate. One of the best ways to investigate the small intestine is using barium.

Barium Enema

What is a barium enema examination? This is a special examination of the large intestines. A Barium-based liquid is introduced throught the anus and rectum to fill the large intestines, so that it shows up clearly on a TV screen and x-ray films. The examination may take about 45 minutes.

What to expect during the examination. The doctor may give you an injection to relax your stomach muscles. You will be asked to lie on an X-Ray couch, and a tube will be inserted gently into your anus. A barium-based liquid will be introduced through the tube into your large intestines, with the doctor observing the filling on an X-Ray TV monitor.Next, the doctor will introduce some air to distend your bowels so that a proper examination can be done. You may experience slight discomfort However it is essential that you try to retain the liquid and air inside until the examination is over.You will be asked to lie in various positions so that X-ray films can be taken of the large intestines in different angles.

After the examination. Drink plenty of water and take fresh fruits and vegetables to prevent constipation.Do not be alarmed if your faeces are white in colour for a few days after the examination, as this is due to the residual barium in your bowels.You are advised not to drive on the day of your examination as the injection given to relax your muscles may sometimes affect your vision temporarily. For an elderly patient, it is best if someone accompanies him/her.

COLON CANCER

Cancer of the colon, a common form of cancer, is a disease in which cancer (malignant) cells are found in the tissues of the colon. The colon is part of the body's digestive system. The digestive system is made up of the esophagus, stomach, and the small and large intestines. The last 6 feet of intestine is called the large bowel or colon. Genes are markers in cells associated with hereditary traits. Abnormal genes have been found in patients with some forms of colon and rectal cancer. Tests are being developed to determine who carries these genes long before cancer appears. Screening tests (such as a rectal examination, proctoscopy, and colonoscopy) may be done regularly in patients who are at higher risk to get cancer. These tests may be done in patients who are over age 50; who have a family history of cancer of the colon, rectum, or of the female organs; who have had small noncancerous growths (polyps) in the colon; or who have a history of ulcerative colitis (ulcers in the lining of the large intestines). A doctor may order these tests to look for cancer if there is a change in bowel habits or if there is any bleeding from the rectum. A doctor will usually begin by giving the patient a rectal examination.The doctor may also want to look inside the rectum and lower colon with a special instrument called a sigmoidoscope or a proctosigmoidoscope. The examination called flexible sigmoidoscopy finds about half of all colon and rectal cancers. Some pressure may be felt, but usually with no pain. The doctor may also want to look inside the rectum and the entire colon (colonoscopy) with a special tool called a colonoscope. This test is usually done in a special Endoscopic Suite by a doctor specially trained in the procedure. Some pressure may be felt, but usually with no pain. If tissue that is not normal is found, the doctor will need to cut out a small piece and look at it under the microscope to see if there are any cancer cells. This is called a biopsy. Biopsies are usually done during the proctoscopy or colonoscopy. The prognosis (chance of recovery) and choice of treatment depend on the stage of the cancer (whether it is just in the inner lining of the colon or if it has spread to other places) and the patient's general state of health. After treatment, a blood test (to measure amounts of carcinoembryonic antigen or CEA in the blood) and x-rays may be done to see if the cancer has come back. Often in the UK a barium enema is performed if there is no blood per rectum but a colon cancer is suspected by the examining doctor.

Special Procedures

Special Procedures are examinations that are usually invasive. Some kind of contrast medium (iodine) is used and a Radiologist performs the procedure. Very little preparation is required for these tests that are available on an outpatient basis. Usually they require about an hour of the patient's time. In this section, we will explain some of these procedures and their preparations.

Hysterosalpingogram

A hysterosalpingogram is an important test that is part of the investigations for infertility. The test is usually done in the radiology department of a hospital in which radiographic contrast (dye) is injected into the uterine cavity through the vagina and cervix. The uterine cavity fills with dye and if the fallopian tubes are open the dye will then fill the tubes and spill out into the abdominal cavity. In this way it can be determined whether the fallopian tubes are open or blocked. The uterine cavity is evaluated for the presence of polyps or fibroids . The fallopian tubes are also examined for any defects within the tube or suggestion of a partial blockage. Usually hysterosalpingogram study only takes about 15-20 minutes to perform. Complications Complications associated with a hysterosalpingogram include the possibility of an allergic reaction to the dye, which is uncommon. This usually manifests as a rash, but can rarely be more serious. Pelvic infection or uterine perforation are also possible complications. Both of these are very uncommon. Some doctors prescribe several days of antibiotics for their patients to attempt to reduce the risk of infection after HSG. Analgesic before the examination may reduce the pain when contrast is injected. Hysterosalpingograms are only done in the first 10 days after a period to make certain you are not pregnant.

Nephrostomy

This is a procedure in which a catheter is placed through your skin into your kidney to drain your urine. An interventional radiologist, who is specially trained, performs this procedure in the Radiology Department. The radiologist may use ultrasound or x-ray imaging to help guide the catheter into exactly the right place to drain your urine. This is done instead of surgery. Blockage of the ureter is a common reason to need a nephrostomy. The kidney makes urine, which drains down the ureter from the kidney to the bladder. When your ureter is blocked, the urine backs up in your kidney. Signs of his are pain and fever, but some people experience no symptoms. The blocked ureter needs treatment because urine cannot drain out of the kidney and the kidney may stop working. The nephrostomy will give the urine a way to leave the kidney. There are other reasons when a nephrostomy may be needed. Please discuss the risks with the Radiologist. Before the procedure starts, you will be given pain medication intravenously. A local anesthetic will also be used to numb the skin and deeper tissues in the area of your back where the catheter will be placed.

There are three major steps to the procedure:

Placement of a needle into the kidney
Placement of a guide wire farther in the kidney
Placement of the drainage catheter

The procedure normally takes 1-2 hours.

Arthrograms

Arthrograms are images made of the sac surrounding the joint space. This area cannot be visualized with x-ray without using contrast media. In a knee arthrogram, a needle is placed under the knee cap in the joint space and contrast agent containing iodine is injected into the space. Meniscal tears can be detected. Other joints which are most commonly examined are the shoulder, ankle and the wrist. This procedure is sometimes carried out prior to an MRI scan of the joint. Examination Time: Approx.1 hour. Precautions: Patients who have an allergy to iodine or local anesthesia should discuss this with the Radiologist prior to the examination. Patient Instructions: Bring recent x-rays of area to be examined.

Venograms

Venograms are x-rays usually made of the vessels in the lower extremity including inferior vena cava, iliac veins, superficial and deep femoral veins and veins in the lower leg and ankle. Contrast agent containing Iodine is injected into a vein in the foot and is examined returning up the leg into the inferior vena cava. Varicosities and obstruction in the lower extremities are well defined by the contrast. Examination Time: Approx. 30 minutes. Precautions: Patients who are allergic to iodine or shellfish and those who suffer from asthma or hayfever should Check with radiologist before scheduling. Note: Patients with a history of renal insufficiency should discuss with the renal physician and the radiologist whether it is safe to go ahead with the procedure.Patient Instructions: An instructions sheet will be given to you by the Radiology Department. Diabetic patients please check with the Radiographer or Radiologist.

IVP / IVU or Intravenous Pyelogram

The examination of the kidneys, ureters and bladder. It requires the intravenous injection of contrast medium (containing iodine). Patient may notice a flushed sensation during the test or very rarely feel slightly nauseated. Examination Time: 30 minutes to 1 hour. Precautions: Patients who suffer from asthma or hayfever or are allergic to iodine or shellfish should check with the radiologist prior to scheduling. Patient Instructions: You will be given an instructions sheet by the Radiology department. Diabetic patients: Check with Radiologist or the Radiographer before scheduling. Patients with a history of renal insufficiency should discuss with the renal physician and the radiologist whether it is safe to go ahead with the procedure.

Sialogram

The test is performed in a hospital radiology department by a Consultant Radiologist. You will be asked to lie on your back on the X-ray table or be seated in a chair. An X-ray is taken before the contrast material is injected to ensure that no stones are present to stop the contrast material from entering the ducts. A catheter (a small flexible tube) will be inserted through your mouth and into the duct of the salivary gland. A contrast medium in then injected into the duct so that the duct will show up on the X-ray. X-rays will be taken from a number of positions. You may be given lemon juice by mouth to help stimulate the production of saliva. Pictures are repeated to examine the drainage of the saliva into the mouth.

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