The potential role of radiolabeled red blood cell scintigraphy in diagnosis of endometriosis

Endometriosis is a gynecological disease and disorder that occurs when endometrial cells are shed through the fallopian tubes and are implanted on the surfaces of pelvis and abdomen. They form lesions that respond to hormones of the menstural cycle and will stimulate inflammation. It is controversial whether [99mTc]Tc-RBC scan would be sufficient for localizing bleeding sites. This study evaluated the value of [99mTc]Tc-RBC in diagnosing endometriosis. Twenty patients were included in the study for endometriosis localization. Between the 2nd and the 5th days of menstruation, when the lesions were highly activated, [99mTc]Tc-RBC scan was performed and compared with TVUS, pelvic MRI and laparoscopic surgery findings. Scans of the patients were reported by two nuclear medicine specialists who were blind to patients’ history. The patients’ age range was 21-48 years (mean age: 35±8.79). The sensitivity, specificity, positive predictive value and negative predictive value for the right pelvic bleeding sites were 73.3%, 80.0%, 91.7% and 50%, respectively while the corresponding indices on the opposite pelvic site were find to be 87.5%, 75.0%, 93.0% and 60%, respectively. Radiolabeled red blood cell scintigraphy has the potential to be used as an alternative procedure for diagnosing endometriosis.