Before you're tested for fibromuscular dysplasia, your doctor may also want to check for atherosclerosis, another condition that can narrow your arteries.

Tests for atherosclerosis usually include:

  • A physical exam
  • A fasting blood test to check your blood sugar and cholesterol levels

The tests you'll have to diagnose fibromuscular dysplasia could include:

  • Catheter-based angiography. During this commonly used test for fibromuscular dysplasia, a thin tube (catheter) is inserted into one of your arteries and moved until it reaches the location your doctor wants to examine. A tiny amount of dye is injected and X-rays are used to examine the location.
  • Doppler ultrasound. Doppler ultrasound can determine if an artery is narrowed by fibromuscular dysplasia.

    In this noninvasive test, an instrument called a transducer is pressed to your skin to send sound waves into your body. The sound waves bounce off red blood cells and body structures, showing how fast your blood flows and the size and shape of the blood vessels.

  • Computerized tomography (CT) angiogram. A CT angiogram allows your doctor to check your arteries to see if they're narrowed or blocked. You'll receive an injection of a dye, and the doughnut-shaped CT scanner will be moved to take images of the artery your doctor believes is narrowed.
  • Magnetic resonance imaging (MRI). This test allows your doctor to see the soft tissues in your body. During an MRI, you lie on a table inside a long tubelike machine that uses a magnetic field and radio waves to capture images from inside your body. Using the images from the test, your doctor may be able to see the cluster of cells narrowing your artery.

The most common form of fibromuscular dysplasia looks like a "string of pearls" on imaging tests. Other, more-aggressive forms of fibromuscular dysplasia have a smooth appearance.

Once you've been diagnosed with fibromuscular dysplasia, your doctor may repeat a Doppler ultrasound exam, a CT angiogram or an MRI angiogram from time to time to see if your condition is getting worse.