Nuclear Medicine Lymphoscintigraphy: Applications and Technical Overview.

Although lymphoscintigraphy is most commonly used for sentinel lymph node mapping, it can also be helpful for evaluating lymphedema, lymphatic malformations, lymphatic leaks, chylous ascites, and chylothorax. Assessment for lymphedema is important because this condition poses significant clinical challenges, and early diagnosis is essential for timely intervention and prevention of complications. Lymphoscintigraphy is a valuable radiologic tool for distinguishing lymphatic causes of edema from nonlymphatic ones, with findings of lymphedema including absent, asymmetric, or delayed drainage from the injection site; dermal backflow; and reduced activity in the inguinal or axillary lymph nodes at lower extremity and upper extremity lymphoscintigraphy. Other supporting evidence of lymphedema may include collateral lymphatic channels and visualization of the deep lymphatic nodes. Additional imaging modalities, such as fluorescence lymphangiography, US, and MR lymphangiography, can also aid in lymphedema assessment. The authors provide an overview of lymphatic physiology, image acquisition, and image interpretation. RSNA, 2025.