Pre-operative Imaging
Your physician may make use of the following imaging modalities to further evaluate your lymphedema and plan for surgery
Your physician may make use of the following imaging modalities to further evaluate your lymphedema and plan for surgery.
Lymphoscintigraphy
Lymphoscintigraphy is a readily available and simple investigation tool for lymphedema. This investigation requires a radioactive dye to be injected via a small injection into the skin at the web space of your affected limb and is performed in the nuclear medicine department of the hospital. Following injection of the dye, a series of scans will be performed at several time intervals; 15 minutes, 30 minutes, 1 hour and 2 hours after injection if necessary.
This investigation will allow your doctor to confirm that the cause of your limb swelling is due to lymphedema. It provides the doctor with valuable information of the severity of your condition and function of the lymphatic vessels in your affected limb. There is a small amount of radiation in this investigation but it provides an excellent bird’s eye view of the lymphatic function of the entire limb affected by lymphedema.
Indocyanine Green (ICG) Lymphangiography
Like lymphoscintigraphy, this investigation allows your doctor to assess the function of the lymphatic vessels in your limb. It may be conveniently performed at the bedside and requires a small injection of a green dye known as ICG into the skin of your affected limb. Using a special infrared camera, your doctor will be able to visualize high resolution images of the superficial lymphatic vessels on your skin. Your doctor can then identify the lymphatic vessels and assess their function based on how well the dye flows. If you are required to undergo surgery for treatment of your lymphedema, this investigation will allow your doctor to mark out the lymphatic vessels on the skin, in preparation for surgery. ICG lymphangiography does not require the use of ionizing radiation. However, unlike lymphoscintigraphy, your doctor is unable to visualize the entire affected limb in a single image.
Magnetic Resonance Lymphangiography (MRL)
Magnetic resonance lymphangiography is a detailed high resolution examination of lymphedema, yielding images of superior resolution compared to lymphoscintigraphy and ICG lymphangiography. It is a specialized examination performed in the radiology department of a hospital. MRL requires a small injection of MRI contrast dye into the web spaces of the affected limb and you will be required to lie in a MRI unit for a period of 1.5 to 2 hours, during which it is important that you follow the instructions of the radiographer in order to acquire optimal images. You will not be able to receive the dye if you have kidney disease.
MRL images provide your doctor with detailed and extremely useful information of the extent and severity of lymphedema for pre-surgery planning. It also determines if the swelling of your limb is caused by fat or fluid accumulation. It also locates deep lymphatics and studies their position in relation to veins. This information would be useful to help determine suitable forms of surgery, be it lymphovenous bypass, liposuction or combination treatment. Your doctor may also request that you undergo MRL for follow up of your condition after surgery. MRL makes use of a strong magnetic field to generate high resolution images and does not require ionizing radiation. If you have a cardiac pacemaker or a cochlear implant, your doctor will have to ensure that your implanted devices are MRI compatible before you can undergo MRL. Compared to lymphoscintigraphy and ICG lymphangiography, MRL will usually incur a higher cost.
Dr. Law Yan Mee
Consultant Radiologist
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