Purpose or Case Report: Lymphoscintigraphy is a minimally invasive first-line imaging technique for the evaluation and management of primary and secondary lymphedema, detection of chylous leaks, and sentinel lymph node mapping. This exhibit will provide an illustrated review of the technique, clinical indications, characteristic imaging findings, and pitfalls in interpretation of lymphoscintigraphic studies in children.
Methods & Materials: Lymphoscintigraphy is routinely performed with a dual-head gamma camera after intradermal injection of small amount of radiolabelled colloidal particles (typically filtered ^99mTc sulfur colloid). Injections are placed in the dorsum of the feet or hands for evaluation of lymphedema and peritumorally for sentinel node studies. Sequential anterior and posterior planar or whole body images are typically obtained within the first 15 minutes, at 45-60 minutes, and 120 minutes with a parallel hole, high-resolution collimator. Delayed imaging may be necessary in many cases. All 92 lymphoscintigraphy procedures performed at our institution between January 2005 to September 2015 in patients 18 years or younger were reviewed in PACS and representative examples were selected for the exhibit.
Results: 1. Primary lymphedema due to congenital lymphatic aplasia or hypoplasia is a more common cause of lymphedema in children and adolescents as compared to secondary lymphedema. Absent visualization of regional lymph nodes, delayed or asymmetric transit of lymph flow, collateral lymphatic channels, and dermal backflow are the key imaging findings in lymphedema.
2. Lymphoscintigraphy is utilized in the assessment of chylous pleural effusion, pericardial effusion, or ascites.
3. Lymphoscintigraphy is essential to sentinel lymph node biopsy, which is used in children with melanoma and sarcomas, such as synovial cell sarcoma and rhabdomyosarcoma.
Conclusions: Lymphoscintigraphy is a simple, reliable and inexpensive diagnostic tool for the functional assessment of lymphatic transit. It usually does not require sedation and the radiation dose to the child is minimal. In the pediatric population, lymphoscintigraphy is most commonly utilized to confirm or exclude lymphatic dysfunction as the cause of a swollen extremity. Pediatric radiologists may guide clinical decisions based on their knowledge and expertise in performing and interpreting lymphoscintigraphic studies.