Imaging of the Urinary Tract

What does "imaging" mean?

In medicine, "imaging" is the general term for any technique used to provide pictures of bones and organs inside the body. Imaging techniques consist of x rays, ultrasound, magnetic resonance imaging (MRI), and computerized tomography (CT) scans. Imaging helps doctors see the causes of medical problems.

What is the urinary tract?

The urinary tract consists of the organs, tubes, and muscles that work together to make, move, store, and release urine, the liquid waste of the human body. The upper urinary tract includes the kidneys, which filter wastes and extra fluid from the blood, and the ureters, which carry urine from the kidneys to the bladder. The lower urinary tract includes the bladder, a balloon-shaped muscle that stores urine, and the urethra, a tube that carries urine from the bladder to the outside of the body during urination. Doctors who specialize in kidney problems are called nephrologists. Doctors who specialize in problems of the organs and tubes that transport urine from the kidneys to outside the body are called urologists. These problems may involve cancers or growths of these organs, including the kidneys, ureters, bladder, and testes, or may involve abnormalities in storing or releasing urine.

What problems could require imaging of the urinary tract?

Imaging may help your doctor find the cause of

One symptom could have several possible causes. Your doctor can use imaging techniques to determine, for example, whether a urinary stone or an enlarged prostate is blocking urine flow. Imaging can also help clarify kidney diseases, tumors, urinary reflux-backward flow of urine-urinary tract infections, incomplete emptying, and small bladder capacity.

What factors will my doctor consider before ordering tests?

The first step in solving a urinary problem is to talk with your doctor. You will be asked about your general medical history, including any major illnesses or surgeries, so you should be prepared to give as many details as you can about the problem and when it started. You should mention all the medicines you take, both prescription and nonprescription, because they might be part of the problem. You should also talk about how much fluid you drink a day and whether the beverages you drink contain alcohol or caffeine.

Why does the doctor choose one imaging technique instead of another?

Your doctor will look at several factors to decide what imaging technique to use. Each has advantages and disadvantages. Convenience and cost-effectiveness are also factors.

Conventional radiology. Doctors have used x-ray machines to diagnose diseases for about a century. X rays of the urinary tract can help highlight a kidney stone or tumor that could block the flow of urine and cause pain. An x ray can also show the size and shape of the prostate. Conventional x rays do involve some exposure to ionizing radiation-radiation that is strong enough to damage some cells. Two x-ray procedures involve the use of contrast medium, which is a liquid that acts like a dye and shows the shape of the urinary tract as it passes through the tract.

Ultrasound. In ultrasound, or sonography, a technician holds a device, called a transducer, that sends harmless sound waves into the body and catches them as they bounce back off the internal organs to create a picture on a monitor. Different angles make it possible to examine different organs.

MRI. MRI machines use radio waves and magnets to produce detailed pictures of internal organs and tissues. No exposure to radiation occurs. With most MRI machines, the patient lies on a table that slides into a tunnel that may be open-ended or closed at one end. Some newer machines are designed to allow the patient to lie in a more open space. During an MRI, the patient is awake but must remain perfectly still while the images are being taken, usually only a few minutes. A sequence of images may be needed to create a detailed picture of the organ. During the sequencing, the patient will hear mechanical knocking and humming noises.

CT scan. CT scans use a combination of x rays and computer technology to create three-dimensional images. Like MRIs, CT scans require the patient to lie on a table that slides into a tunnel. CT scans can help identify stones in the urinary tract, infections, cysts, tumors, and traumatic injury to the kidneys and ureters.

How do I prepare for an imaging examination?

How you prepare will depend on the purpose of the examination and the type of equipment to be used. You should listen to your doctor's instructions carefully and ask questions if you do not understand something that is said.

What are the test procedures like?

Most procedures for imaging the urinary tract are performed as the patient lies on a table.

What should I do after the test?

For most of these tests, you will be able to resume normal activity immediately afterward. If your test involved placing a catheter in the urethra, you may have some mild discomfort. Drinking an 8-ounce glass of water every 30 minutes for 2 hours should help. Also, you may be able to take a warm bath. Alternatively, holding a warm, damp washcloth over the urethral opening may relieve the discomfort.

You may experience some discomfort after a transrectal ultrasound as well. A prostate biopsy may produce pain in the rectum and the perineum-the area between the rectum and the scrotum.

For catheterization or biopsy, your doctor will sometimes, but not always, give you an antibiotic to take for 1 or 2 days to prevent an infection. If you notice signs of infection-including chills, fever, or persistent pain when you urinate-you should call your doctor at once.

When will I get the results?

Results for simple tests can be discussed with your doctor or nurse immediately after the test. Other results may take a few days. You will have the chance to ask questions about the results and possible treatments for your problem.