Polycystic Kidney Disease

Diagnosis

Mayo Clinic specialists use several diagnostic methods to identify PKD. These methods detect the size and number of cysts and evaluate the amount of healthy kidney tissue.

• Ultrasound examination — Physicians use this method to evaluate the shape and size of the kidney. During an ultrasound exam, a wand-like device called a transducer is placed on the body. The transducer emits safe, inaudible sound waves, which are then reflected back from the body to the transducer, much like active sonar. A computer translates the reflected sound waves into a moving image of the kidney as it functions.
• Computerized tomography (CT) scan — Physicians use this method to produce a two-dimensional image of the kidneys. During a CT scan, the patient lies on a movable table that is guided through a doughnut-shaped device that passes very thin X-ray beams through the body.
• Magnetic resonance imaging (MRI) scan — Physicians use this method to determine the volume of the kidney and identify any cysts that may be present. During a MRI, the patient lies inside a large cylinder in which magnetic fields and radio waves generate a cross-sectional view of the kidneys.
• Genetic testing — Gene linkage analysis involves special blood tests for the patient and at least three family members who are known to have or not to have polycystic kidney disease. Results of the patient's blood test are compared to those of the family members. This test is often used when one family member is considering donating a kidney to another family member for a living donor kidney transplant. Genetic testing can also be used when imaging results do not yeild a clear answer and a definitive diagnosis is needed.