Pre-operative Imaging
Pre-operative Imaging
Your doctor may use the following imaging techniques to better assess your lymphedema and help plan any necessary surgical treatment.
Lymphoscintigraphy
Lymphoscintigraphy
Lymphoscintigraphy is a commonly used and straightforward imaging test to help diagnose lymphedema. It involves injecting a small amount of radioactive dye just under the skin, usually in the web space between the fingers or toes of the affected limb. The test is carried out in the hospital’s nuclear medicine department.
After the injection, a series of scans are taken over time—typically at 15 minutes, 30 minutes, 1 hour, and up to 2 hours—to track how the dye moves through your lymphatic system.
This test helps your doctor:
- Confirm whether your swelling is caused by lymphedema
- Assess how well your lymphatic vessels are working
- Determine the severity of the condition
Although a small amount of radiation is involved, the test is safe and provides a valuable overview of the lymphatic flow in the affected limb.
Indocyanine Green (ICG) Lymphangiography
Indocyanine Green (ICG) Lymphangiography
ICG lymphangiography is another imaging method used to evaluate how well your lymphatic vessels are working. It’s a simple, bedside procedure that involves injecting a small amount of a green dye (called Indocyanine Green or ICG) just under the skin of your affected limb.
Using a special infrared camera, your doctor can see detailed images of the surface-level lymphatic vessels and observe how the dye moves through them. This helps identify which vessels are working properly and which may be damaged.
If surgery is planned, ICG lymphangiography is especially useful—it allows your doctor to map out the lymphatic vessels on your skin to guide the procedure.
Unlike lymphoscintigraphy, ICG does not use any radiation. However, it only shows the lymphatic vessels near the surface and not the entire limb in one view.
Magnetic Resonance Lymphangiography (MRL)
Magnetic Resonance Lymphangiography (MRL)
MRL is an advanced imaging test that provides highly detailed pictures of the lymphatic system. It offers much higher resolution than lymphoscintigraphy or ICG lymphangiography and is typically used for detailed assessment and surgical planning.
This test is done in the radiology department of a hospital. A small amount of contrast dye is injected into the web spaces of your affected limb, and you’ll lie inside an MRI scanner for about 1.5 to 2 hours. It’s important to stay still and follow the radiographer’s instructions to get the best images.
MRL helps your doctor to:
- Assess the extent and severity of your lymphedema
- Determine if the swelling is caused by fluid or fat
- Locate deeper lymphatic vessels and understand their relationship with veins
- Plan the most suitable treatment, such as lymphovenous bypass, liposuction, or combination therapies
- Monitor progress after surgery
MRL uses a strong magnetic field and does not involve any radiation. However, it’s not suitable for patients with certain implants (like pacemakers or cochlear implants) unless they are MRI-safe. Also, patients with kidney disease may not be able to receive the contrast dye.
Compared to other imaging methods, MRL is typically more expensive due to its detailed imaging and specialized equipment.
Dr. Law Yan Mee
Consultant Radiologist
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