Diagnosis

For polycystic kidney disease, certain tests can detect the size and number of kidney cysts you have and evaluate the amount of healthy kidney tissue, including:

• Ultrasound. During an ultrasound, a wandlike device called a transducer is placed on your body. It emits sound waves that are reflected back to the transducer — like sonar. A computer translates the reflected sound waves into images of your kidneys.
• CT scan. As you lie on a movable table, you're guided into a big, doughnut-shaped device that projects thin X-ray beams through your body. Your doctor is able to see cross-sectional images of your kidneys.
• MRI scan. As you lie inside a large cylinder, magnetic fields and radio waves generate cross-sectional views of your kidneys.