Qualitative evaluation of magnetic resonance imaging features in aneurysmal bone cysts after percutaneous...

Aneurysmal bone cysts (ABCs) are benign vascular lesions commonly affecting the pediatric population.

To assess magnetic resonance imaging (MRI) features of ABCs after percutaneous cryoablation.

A retrospective review of the hospital's electronic medical record database was conducted to identify patients who underwent percutaneous image-guided cryoablation for aneurysmal bone cysts between March 2014 and April 2024. Patients were excluded if they lacked pre- or post-treatment MRI, underwent surgical curettage and bone grafting between cryoablation treatments, or received adjunctive therapies such as sclerotherapy or bone grafting. Demographic data and pre- and post-cryoablation MRI characteristics of the lesions were collected and analyzed.

We retrospectively analyzed 20 patients (mean age = 14.6 years). The average ABC volume decreased from 83 cm³ pre-treatment to 32.7 cm³ post-treatment. In the final post-treatment MRI, there was a 50% decrease in the cystic component in 90% (n = 18) of patients, improved cortical integrity in 75% (n = 9), resolution of peri-lesional edema and mass effect in all (n = 20), and development of organized fibrosis in 50% (n = 10) of the patients. The average time was 8.3 months for a 50% reduction in cystic component, 7.3 months for improvement in cortical integrity, 6.4 months for improvement in mass effect, 15 months for complete resolution of peri-lesional enhancement, and 16.1 months for the development of organized fibrosis.

These findings suggest MRI is a valuable tool for monitoring ABC response to cryotherapy, guiding future treatment protocols.