Kidney, Ureter, and Bladder X-ray (2023)

What is a kidney, ureter, and bladder X-ray?

A kidney, ureter, and bladder (KUB) X-ray may be performed to assess the abdominal area for causes of abdominal pain, or to assess the organs and structures of the urinary and/or gastrointestinal (GI) system. A KUB X-ray may be the first diagnostic procedure used to assess the urinary system.

X-rays use invisible electromagnetic energy beams to produce images of internal tissues, bones, and organs on film. X-rays are made by using external radiation to produce images of the body, its organs, and other internal structures for diagnostic purposes. X-rays pass through body tissues onto specially treated plates (similar to camera film) and a "negative" type picture is made (the more solid a structure is, the whiter it appears on the film). Digital films and digital media are more commonly used now than the film media.

Other related procedures that may be used to diagnose problems of the urinary organs of the abdomen include computed tomography (CT scan) of the kidney , kidney ultrasound , kidney scan , cystography , cystometry , cystoscopy , intravenous pyelogram , kidney biopsy , magnetic resonance imaging (MRI) , prostate ultrasound , retrograde cystography , retrograde pyelogram , uroflowmetry , and renal venogram .

How does the urinary system work?

Urinary system parts and their functions:

• Two kidneys. This pair of purplish-brown organs is located below the ribs toward the middle of the back. Their function is to:

  • remove liquid waste from the blood in the form of urine

  • keep a stable balance of salts and other substances in the blood

  • produce erythropoietin, a hormone that aids the formation of red blood cells

  • regulate blood pressure

The kidneys remove urea from the blood through tiny filtering units callednephrons. Each nephron consists of a ball formed of small bloodcapillaries, called a glomerulus, and a small tube called a renal tubule.Urea, together with water and other waste substances, forms the urine as itpasses through the nephrons and down the renal tubules of the kidney.

• Two ureters. These narrow tubes carry urine from the kidneys to the bladder. Muscles in the ureter walls continually tighten and relax forcing urine downward, away from the kidneys. If urine backs up, or is allowed to stand still, a kidney infection can develop. About every 10 to 15 seconds, small amounts of urine are emptied into the bladder from the ureters.

• Bladder. This triangle-shaped, hollow organ located in the pelvis. It is held in place by ligaments that are attached to other organs and the pelvic bones. The bladder's walls relax and expand to store urine, and contract and flatten to empty urine through the urethra. The typical healthy adult bladder can store up to two cups of urine for two to five hours.

• Two sphincter muscles. These circular muscles help keep urine from leaking by closing tightly like a rubber band around the opening of the bladder.

• Nerves in the bladder. The nerves alert a person when it is time to urinate, or empty the bladder.

• Urethra. This tube allows urine to pass outside the body. The brain signals the bladder muscles to tighten, which squeezes urine out of the bladder. At the same time, the brain signals the sphincter muscles to relax to let urine exit the bladder through the urethra. When all the signals occur in the correct order, normal urination occurs.

Facts about urine:

• Adults pass about a quart and a half of urine each day, depending on the fluids and foods consumed.

• The volume of urine formed at night is about half that formed in the daytime.

• Normal urine is sterile. It contains fluids, salts and waste products, but it is free of bacteria, viruses, and fungi.

• The tissues of the bladder are isolated from urine and toxic substances by a coating that discourages bacteria from attaching and growing on the bladder wall.

Reasons for the procedure

A KUB X-ray may be performed to help diagnose the cause of abdominal pain,such as masses, perforations, or obstruction. A KUB X-ray may be taken toevaluate the urinary tract before other diagnostic procedures areperformed. Basic information regarding the size, shape, and position of thekidneys, ureters, and bladder may be obtained with a KUB X-ray. Thepresence of calcifications (kidney stones) in the kidneys or ureters may be noted.

There may be other reasons for your doctor to recommend a KUB X-ray.

Risks of the procedure

You may want to ask your doctor about the amount of radiation used duringthe procedure and the risks related to your particular situation. It is agood idea to keep a record of your past history of radiation exposure, suchas previous scans and other types of X-rays, so that you can inform yourdoctor. Risks associated with radiation exposure may be related to thecumulative number of X-ray examinations and/or treatments over a longperiod of time.

Notify your health care provider if you are pregnant or suspect that youmay be pregnant. Radiation exposure during pregnancy may lead to birthdefects.

There may be other risks depending on your specific medical condition. Besure to discuss any concerns with your physician prior to the procedure.

Certain factors or conditions may interfere with the accuracy of a KUBX-ray. These factors include, but are not limited to, the following:

• Recent barium X-rays of the abdomen

• Gas , feces, or foreign body in the intestine

• Uterine or ovarian masses, such as calcified fibromas of the uterus or ovarian lesions

Before the procedure

• Your doctor will explain the procedure to you and offer you the opportunity to ask any questions that you might have about the procedure.

• Generally, no prior preparation, such as fasting or sedation, is required.

• Notify the radiologic technologist if you are pregnant or suspect you may be pregnant.

• Notify your doctor and radiologic technologist if you have taken a medication that contains bismuth, such as Pepto-Bismol, in the past four days. Medications that contain bismuth may interfere with testing procedures.

• Based on your medical condition, your doctor may request other specific preparation.

During the procedure

A KUB X-ray may be performed on an outpatient basis or as part of your stayin a hospital. Procedures may vary depending on your condition and yourdoctor's practices.

Generally, a KUB X-ray follows this process:

1. You will be asked to remove any clothing, jewelry, or other objects that might interfere with the procedure.

2. If you are asked to remove clothing, you will be given a gown to wear.

3. You will be positioned in a manner that carefully places the part of the abdomen that is to be X-rayed between the X-ray machine and a cassette containing the X-ray film or digital media. You may be asked to stand erect, to lie flat on a table, or to lie on your side on a table, depending on the X-ray view your doctor has requested. You may have X-rays taken from more than one position.

4. Body parts not being imaged may be covered with a lead apron (shield) to avoid exposure to the X-rays.

5. Once you are positioned, the radiologic technologist will ask you to hold still for a few moments while the X-ray exposure is made.

6. It is extremely important to remain completely still while the exposure is made, as any movement may distort the image and even require another X-ray to be done to obtain a clear image of the body part in question.

7. The X-ray beam will be focused on the area to be photographed.

8. The radiologic technologist will step behind a protective window while the image is taken.

While the X-ray procedure itself causes no pain, the manipulation of thebody part being examined may cause some discomfort or pain, particularly inthe case of a recent injury or invasive procedure, such as surgery. Theradiologic technologist will use all possible comfort measures and completethe procedure as quickly as possible to minimize any discomfort or pain.

After the procedure

Generally, there is no special type of care following a KUB X-ray. However,your doctor may give you additional or alternate instructions after theprocedure, depending on your particular situation.