How are simple kidney cysts diagnosed?
Most simple kidney cysts are found during imaging tests done for other reasons. When a cyst is found, the following imaging tests can be used to determine whether it is a simple kidney cyst or another, more serious condition.
These imaging tests are performed at an outpatient center or hospital by a specially trained technician, and the images are interpreted by a radiologist—a doctor who specializes in medical imaging. Ultrasound may also be performed in a health care provider’s office. Anesthesia is not needed though light sedation may be used for people with a fear of confined spaces who undergo magnetic resonance imaging (MRI).
Ultrasound
Ultrasound uses a device, called a transducer, that bounces safe, painless sound waves off organs to create an image of their structure. An abdominal ultrasound can create images of the entire urinary tract. The images can be used to distinguish harmless cysts from other problems.
Computerized tomography (CT) scan
CT scans use a combination of x-rays and computer technology to create three-dimensional (3-D) images. A CT scan may include the injection of a special dye, called contrast.
CT scans require the person to lie on a table that slides into a tunnel-shaped device where the x-rays are taken. CT scans can show cysts and tumors in the kidneys.
MRI
MRI machines use radio waves and magnets to produce detailed pictures of the body’s internal organs and soft tissues without using x-rays. An MRI may include the injection of a contrast medium. With most MRI machines, the person lies on a table that slides into a tunnel-shaped device that may be open-ended or closed at one end; some newer machines are designed to allow the person to lie in a more open space. Like CT scans, MRIs can show cysts and tumors.
How are simple kidney cysts treated?
Treatment is not needed for simple kidney cysts that do not cause any symptoms. Simple kidney cysts may be monitored with periodic ultrasounds.
Simple kidney cysts that are causing symptoms or blocking the flow of blood or urine through the kidney may need to be treated using a procedure called sclerotherapy. In sclerotherapy, the doctor punctures the cyst using a long needle inserted through the skin. Ultrasound is used to guide the needle to the cyst. The cyst is drained and then filled with a solution containing alcohol to make the kidney tissue harder. The procedure is usually performed on an outpatient basis with a local anesthetic.
If the cyst is large, surgery may be needed. Most surgeries can be performed using a laparoscope—a special tool with a small, lighted video camera. The procedure is usually done under general anesthesia in a hospital. The surgeon drains the cyst and then removes or burns away its outer tissue. This type of surgery allows for a smaller incision and quicker recovery.