Imaging paediatric bone marrow in immunocompromised patients.

The bone marrow of immunocompromised patients may exhibit abnormalities due to the underlying disease, adverse treatment effects, and/or complications arising from either source. Such complexity poses a significant diagnostic challenge, particularly in children. Magnetic resonance imaging (MRI) is the modality of choice when evaluating bone marrow in these patients. The high soft tissue contrast of MRI studies allows for detailed evaluation of bone marrow composition, including fat content, cellularity, and vascularisation. During the early years of life, bone marrow undergoes physiological maturation manifesting as a wide range of MRI findings. Understanding the most common MRI features during this phase of development is essential. However, it is equally critical to recognise physiological variations that can mimic pathological changes, as distinguishing between variations and truly pathological abnormalities is crucial for accurate diagnosis and management. This article reviews normal bone marrow and its variations during childhood, as well as the most common alterations presenting in immunocompromised patients.