Contributions of SPECT/CT imaging to the lymphoscintigraphic investigations of the lower limb lymphedema.

Lymphoscintigraphy is a safe and reliable technique for investigating lymphedema. However, interpretation of delayed planar conventional imaging may be questionable due to the superimposition of soft tissues. Therefore, the aim of this retrospective study was to evaluate the contribution of single photon emission computed tomography/computed tomography (SPECT/CT) to lymphoscintigraphic investigation in a selected population with abnormal interstitial activity. Forty one patients with lower limb lymphedema either primary (n=17) or secondary (n=5), or associated with chronic venous insufficiency (n=19) underwent lymphoscintigraphy according to a standard protocol. SPECT/CT imaging that started immediately after planar imaging covered the part of the lower limbs with the most significant interstitial activity. The CT images were also analyzed separately to identify the typical honeycomb pattern of lymphedema. SPECT/CT identified additional abnormalities in vessels and soft tissues in 19 patients (46%). The additional information, primarily related to dermal collateralization of flow, dermal backflow, lymphangioma, and lymphorrhea, aided in understanding the physiopathology of edema and may have influenced management in 35 patients (85%). The honeycomb appearance of the soft tissues was noted on CT in most patients (90%). This study suggests that SPECT/CT is a promising addition to planar imaging in lymphoscintigraphic investigations of lymphedema.