Multimodality imaging findings of infected endometriomas: "T1 signal reversal" as a potential diagnostic sign?

Endometrioma superinfection is a rare clinical entity that may cause diagnostic confusion and can be complicated by rupture, peritonitis, sepsis, and even death. Therefore, early diagnosis is crucial for appropriate patient management. Since clinical findings can be mild or nonspecific, radiological imaging is frequently used for diagnostic purposes. From a radiological perspective, it can be challenging to distinguish the presence of infection in an endometrioma. Complex cyst structure, wall thickening, increased peripheral vascularization, nondependent air bubbles, and surrounding inflammatory changes have been reported as potential US and CT findings suggestive of superinfection. On the other hand, there is a gap in the literature regarding MRI findings. To the best of our knowledge, this is the first case report in the literature to discuss MRI findings and temporal evolution of infected endometriomas. In this case report, we aim to present a patient with bilateral infected endometriomas at different stages, and to discuss the multimodality imaging findings, focusing specifically on the MRI. We defined 2 new MRI findings that may indicate the presence of superinfection in the early period. The first one was the "T1 signal reversal" seen in bilateral endometriomas. The second one, "progressive disappearance of T2 shading," was observed only in the right-sided lesion. These nonenhancing signal changes accompanied by increased lesion sizes during MRI follow-up were thought to represent a transition from blood to pus, and the percutaneous drainage of the right-sided endometrioma microbiologically confirmed our suspicion. In conclusion, MRI can be helpful in the early diagnosis of infected endometrioma due to its high soft tissue resolution. Percutaneous treatment may contribute to patient management as an alternative to surgical drainage.