Characteristic Single Photon Emission Computed Tomography-Computed Tomography (SPECT-CT) Findings in Secondary Genital Lymphedema.

Diagnosis and evaluation of genital lymphedema (GL) is a challenging yet crucial step in the treatment of GL. Single photon emission computed tomography-computed tomography (SPECT-CT) is useful for lymph flow imaging, but its characteristic findings for GL are not clarified. The purpose of this study was to uncover characteristic SPECT-CT findings in secondary GL. Medical records of patients who underwent SPECT-CT and indocyanine (ICG) lymphography for evaluation of secondary lower extremity lymphedema (LEL) and/or genital lymphedema (GL) were reviewed. Characteristic SPECT-CT findings were identified based on timing, visibility, and extension of lymphatic enhancement in the lower abdominal, inguinal, genital, and pelvic regions. Patients were divided into either GL group with genital ICG lymphography stage I-V or control group with stage 0. Prevalence of each SPECT-CT finding was compared between the groups. Ten female patients were included; 7 (70%) were classified in GL group, and 3 (30%) in control group. Characteristic SPECT-CT findings included pauci-enhancement of inguinal lymph nodes (PEIL), genital dermal back flow, external iliac lymph nodes non-enhancement, common iliac lymph nodes non-enhancement, and periaortic lymph nodes non-enhancement. There was a statistically significant difference between GL and control groups for PEIL (100% vs. 0%, P = 0.002). Characteristic SPECT-CT findings in secondary GL were identified. Further studies are warranted to clarify usefulness of the findings for management of GL.