Purpose or Case Report: Osteonecrosis (ON) is a significant complication in pediatric oncology, characterized by bone tissue death due to impaired blood supply. It most commonly affects poorly vascularized bones, such as the femoral head, distal femur, and proximal tibia. In children with oncohematological diseases, ON is often multifactorial—linked to prolonged corticosteroid therapy, chemotherapy, and underlying systemic conditions. Prevalence can reach up to 40% in high-risk groups.

This educational poster aims to equip radiologists with practical imaging strategies for early detection and staging of ON, enhancing diagnostic confidence and multidisciplinary collaboration. This work builds on institutional experience at a high-complexity pediatric hospital, integrating recent imaging protocols and outcome data to refine diagnostic pathways.

Early diagnosis is crucial, as ON is frequently asymptomatic and multifocal at onset. Magnetic resonance imaging (MRI) is the gold standard for early detection, with whole-body MRI protocols enabling comprehensive screening of asymptomatic patients. MRI findings include bone marrow edema and geographic areas of necrosis, often surrounded by the characteristic double line sign. Advanced stages show subchondral collapse, loss of sphericity, and cartilage irregularity, which can be graded using systems such as Niinimäki, Ficat and Arlet, or ARCO.

The use of whole-body MRI for asymptomatic screening represents a proactive approach that may reduce long-term disability in pediatric oncology patients. Conventional radiography is useful for assessing bone structure and detecting late-stage changes, while computed tomography (CT) is reserved for preoperative planning. Treatment strategies depend on the severity and location, ranging from conservative management (corticosteroid withdrawal, bisphosphonates, load reduction) to surgical interventions such as core decompression or, in severe cases, joint replacement. Imaging plays a key role not only in early diagnosis but also in monitoring treatment response and guiding surgical planning.
Imaging also plays an important role in complications, that include acute subchondral fractures and superinfection, which require prompt recognition and management.

Radiologists play a pivotal role in early detection. Familiarity with imaging patterns and grading systems is essential to guide timely intervention and improve long-term outcomes.
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