Imaging intraosseous hemangiomas: Typical and atypical features across modalities.

Intraosseous hemangiomas are benign vascular lesions within osseous structures, often found incidentally in the spine. Their imaging appearance consists of a variable mixture of fat, vascular channels, and remodeled trabecular bone. Fat-rich lesions typically have characteristic findings, including but not limited to vertically-oriented trabeculae on radiographs, a "polka-dot" pattern on axial computed tomography (CT), a "corduroy" pattern on sagittal or coronal CT, and hyperintensities on both T1- and T2-weighted magnetic resonance imaging (MRI). Conversely, atypical lesions are lipid-poor and may be T1 hypointense and less conspicuous on CT. Imaging appearance may overlap with metastatic disease and other marrow-replacing processes. Aggressive hemangiomas represent an important clinical subset often characterized by osseous expansion, cortical disruption, and epidural or paravertebral extension, pathologic fracture, or neurologic compromise. In current practice, the evaluation of vertebral hemangiomas with nuclear medicine can be challenging due to highly variable and often non-specific radiotracer uptake. On technetium-99m (99mTc) bone scintigraphy, lesions are often inconspicuous, although decreased or increased uptake may occur. On fluorine-18 fluorodeoxyglucose (FDG) PET/CT, hemangiomas are usually non-avid or mildly avid, but occasional marked uptake should not be interpreted in isolation. Uptake on prostate-specific membrane antigen (PSMA)- and somatostatin receptor (SSTR)-targeted PET is similarly inconsistent. Regardless of the radiotracer used, correlation with prior imaging, particularly on CT and MRI, is more reliable than assessing radiotracer avidity alone. This review presents a practical multimodal framework for recognizing typical, atypical, and aggressive intraosseous hemangiomas in adult and pediatric presentations with common nuclear medicine interpretation pitfalls.