To provide an in-depth review of pelvic bone changes observed on MRI following pelvic radiotherapy. To distinguish between metastases and common radiation-induced changes in the pelvic bone, such as radiation osteitis, osteoradionecrosis, and insufficiency fractures. To increase awareness among radiologists for more accurate diagnosis and management.

In 2022 the incidence and mortality of cervical carcinoma all around the world was 14.1 and 7.1/100.000 women, respectively according to the Global Cancer Observatory (1). Radiotherapy (RT) is the crucial and standard treatment choice for cervical carcinoma, especially stage IIB and over-stage cancer (2-5). However, radiation exposure can lead to bone alterations that may mimic pathological conditions such as metastasis, infection, or osteonecrosis. The effect of radiation on healthy bone marrow and bone structure can be evaluated in a wide spectrum, that is, while...

Radiation-induced changes in bone are primarily identified using MRI, which is highly sensitive to both bone marrow and structural alterations (8-9).Typical imaging findings for radiation osteitis include: (10) T2W and STIR : Hyperintense signals indicative of bone marrow edema. T1W : Hypointense or isointense signals depending on the stage of the condition. Early radiation osteitis often retains normal T1-weighted signal characteristics, while later stages may exhibit diffuse hypointensity. T1W + contrast: Diffuse or patchy enhancement in active inflammation or reparative processes. For osteoradionecrosis, imaging findings...

Radiological imaging plays a pivotal role in understanding and managing radiotherapy-induced bone changes. MRI remains the gold standard for detecting early and dynamic changes in bone marrow, with T2W and STIR sequences highlighting edema and T1W images revealing structural alterations. Over time, MRI allows clinicians to monitor the progression or resolution of radiation osteitis and differentiate it from more severe conditions such as osteoradionecrosis. CT and PET-CT complement MRI by providing detailed insights into structural deformities and metabolic activity, aiding in accurate diagnosis. Recognizing these...

H. Kose: Nothing to disclose H. Aydin: Nothing to disclose I. Kızıldağ Yırgın: Nothing to disclose M. G. Dagoglu Kartal: Nothing to disclose

1- https://gco.iarc.who.int2-Manganaro, Lucia et al. “Staging, recurrence and follow-up of uterine cervical cancer using MRI: Updated Guidelines of the European Society of Urogenital Radiology after revised FIGO staging 2018.”European radiologyvol. 31,10 (2021)3-Zeng SY, Li LY, Shu KY, Pan M, Li HP, Luo B (2008) Concurrent chemoradiotherapy versus radiotherapy in advanced cervical carcinoma. Ai Zheng 27:942–946 3.4-Meyer LA, Bohlke K, Wright AA (2016) Postoperative Radiation Therapy for Endometrial Cancer: American Society of Clinical Oncology Clinical Practice Guideline Endorsement of the American Society for Radiation Oncology Evidence-Based...