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Application of limb lymphoscintigraphy in the diagnostic workup of lymphedema Ramin Sadeghi, M.D. Nuclear Medicine Specialist Associate Professor DSNMC Nuclear Medicine Research Center (NMRC; MUMS) www.DSNMC.ir

Lymphedema Etiology Secondary Primary The most common type Due to surgery, radiotherapy, trauma, etc Primary Due to congenital abnormalities of the lymphatic system Categorized according to the time of presentation Congenital Precox Tarda

Stemmer’s sign: Negative

Stemmer’s sign: Positive

Technique Sub-cutaneous injection of 1 or 2 injections of Tc-99m- Antimony Sulfide Colloid or Phytate (0.5 mCi each) in the interdigital webs Imaging A whole body imaging from the injection site to the liver 10-12 cm/min: Preferably faster 1 to 4 hours post injection

Case 1 43 y/o female patient with mild bilateral pitting edema of the lower limbs

Normal Early Delayed

Normal lymph flow Symmetric visualization of the inguinal lymph nodes on the early and delayed images. Sometimes lymph vessels can be visualized No other abnormal activity in the limbs

Imaging criteria for impairment of lymphatic drainage (Lymphedema) No lymph node visualization Visualization of ≤3 lymph nodes in the inguinal areas on both early and delayed images Dermal backflow Visualization of the intercalary node (epitrochlear or politeal) Quantitative analysis: Significantly reduced uptake in the inguinal area (<1.5% of the injection side) Significant asymmetry of the inguinal uptake (< 50% of the amount in the contra-lateral limb on the early or delayed images)

Case 2 31 y/o female with severe non pitting edema of the left lower limb started since birth

Lymphedema of the left lower limb No lymph node visualization Early Delayed

Primary vs. secondary lymphedema Not possible to be distinguished by lymphoscintigraphy

Case 29 y/o female patient with the history of the right axillary surgery for accessory breast 8 month before. Progressive edema since then

Early Delayed

Patient with progressive edema of the left lower limb after pelvic surgery

Case 39 y/o female with non-pitting edema of the right lower limb since 7 years ago and mild pitting edema of the left lower limb.

Bilateral lymphedema of the lower limbs Visualization of ≤3 lymph nodes in the inguinal areas on both early and delayed images Early Delayed

Case 4 18 y/o female patient with the history of 2 year pitting edema of the right lower limb. Minimal intermittent swelling on the left side.

Bilateral lymphedema of the lower limbs Visualization of the intercalary node ( politeal) Early Delayed

Case 6 40 y/o male patient with the history of left lower limb swelling since 20 years ago.

Lymphedema of the left lower limb Dermal backflow Early Delayed

Case 6a 15 y/o male with progressive swelling of the lower extremities (more on the left side)

Bilateral Dermal backflow Early Delayed

Quantitative imaging Significantly reduced uptake in the inguinal area (<1.5% of the injection side) Significant asymmetry of the inguinal uptake (< 50% of the amount in the contra-lateral limb on the early or delayed images)

Quantitative approach Without quantitative approach the sensitivity of lymphoscintigraphy would be low for detection of lymphedema Inguinal to injection site ratio is important Use the geometric or arithmetic mean for ant/post images Values for different pathologies Normal: >8-10% Lipedema: 3-4% Lymphedma: <1.5% (for lower limbs)

Anterior Posterior Anterior Posterior Early Delayed Left 6% Right 2%

Case 7a A 60 year old patient with puffy edema of the lower limbs. Lipedema with superimposed lymphedema

L: 4.5%

Case 8 14 y/o male with bilateral mild swelling of the limbs since 3 months ago

Bilateral impairment of lymphatic drainage intercalary node Early Delayed

Normal distribution of the tracer Tc-99m Phytate Kidneys Bladder Growth plates Tc-99m Antimony Sulfide Colloid Less intense activity in the renal system

Case 9 23 y/o male with history of right lower extremity swelling since 4 years ago. No history of trauma. The swelling started proximally from the groin and scrotum. There were small blisters on these areas and the patient reported occasional oozing of milky fluid for several days. A skin biopsy was taken from right groin and showed lymphangectasia. Referred for diagnosis of possible lymphatic refulx

Injection technique? Injection only on the non-affected side

Case 9 Cont. The patient underwent surgery for ligation of the abnormal pelvic lymphatic trunks

Case 10a A 7 year old child with progressive four limb edema

Global nature of lymphedema Lymphedema is usually due to defect in the superficial lymphatic network and is a global disease in the body Apparently normal limbs can have impaired lymphatic flow

Case 10b A 30 year old female with right lower limb edema for 10 years. No sign of edema on the left side

V.R.Dabbagh; DSNMC; www.DSNMC.ir