Tests and diagnosis

By Mayo Clinic Staff

Your doctor may try to rule out other causes of swelling when diagnosing lymphedema. Swelling can have many causes, including a blood clot or an infection that doesn't involve your lymph nodes.

If you're at risk of lymphedema — for instance, if you've recently had cancer surgery involving your lymph nodes — your doctor may diagnose lymphedema based on your signs and symptoms.

If the cause of your lymphedema isn't as obvious, your doctor may order imaging tests to determine what's causing your signs and symptoms. To get a look at your lymphatic system, your doctor may use an imaging technique, such as:

  • Magnetic resonance imaging (MRI). Using a magnetic field and radio waves, an MRI produces 3-D, high-resolution images. An MRI gives your doctor a better look at the tissues in your arm or leg. He or she might be able to use an MRI to see characteristics of lymphedema.
  • Computerized tomography (CT). A CT scan — also called computerized tomography, or just CT — is an X-ray technique that produces detailed, cross-sectional images of your body's structures. CT scans can reveal areas of the lymphatic system that may be blocked.
  • Doppler ultrasound. This variation of the conventional ultrasound looks at blood flow and pressure by bouncing high-frequency sound waves (ultrasound) off red blood cells. Ultrasound can be helpful in finding obstructions.
  • Radionuclide imaging of your lymphatic system (lymphoscintigraphy). During this test you're injected with a radioactive dye and then scanned by a machine. The resulting images show the dye moving through your lymph vessels, highlighting areas where the lymph fluid is blocked.
Nov. 15, 2011

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