Premensturation Hyperemia of the Uterus and Endometrial Shedding on Delayed RBC Scan​​​​​​

We present the case of a 44-year-old woman with a recent history of liver transplantation who underwent 99m Tc-RBC scan to identify the source of melena. Initial imaging revealed a zone of increased radiotracer uptake in the hypogastric region. SPECT/CT localized this uptake to the uterus. Delayed imaging performed the following day showed a focal zone in the same region, which was localized to the uterine cavity on the second SPECT/CT, consistent with endometrial shedding during menstruation. Our case emphasizes the importance of SPECT/CT to reduce the false positives of the RBC scan.