MR imaging characteristics of osteoradionecrosis of the pelvis after radiation therapy on gynecological tumors.

PURPOSE: To describe MR imaging characteristics of osteoradionecrosis (ORN) of the pelvis as a result of radiation therapy (RT) on gynecological tumors.

MATERIAL AND

METHODS

Radiography, computed tomography (CT) and magnetic resonance imaging (MRI) were performed on 9 women (mean age 67.5 years) with gynecological tumors to identify ORN. T1- and T2-weighted sequences and contrast-enhanced t1-weighted sequences with and without fat saturation were used. The patients began developing pain after the completion of RT indicating a possible ORN a which time MRI was performed. MR images were correlated with the results of clinical examinations.

RESULTS

Depending on the time elapsed after RT, ORN presented with different signal intensities. The acquired images suggested that signal changes in T2-weighted images as well as the different enhancement behaviour of ORN could be dependent on the time elapsed after RT. Visualisation of the affected regions was best achieved with fat-saturated T1-weighted sequences. CT showed increased density in the affected regions corresponding to osteosclerosis. In all cases the sacroiliac joint was affected, some times bilaterally.

CONCLUSION

MRI is helpful in detecting and characterizing ORN. Changes in signal intensity, based on histopathological tissue changes could make a chronological classification possible.