[The magnetic resonance tomography of Ewing's sarcomas: the morphology and tumor extension]

Abstract

Purpose: The morphology and delineation of Ewing sarcoma in magnetic resonance imaging was investigated.

Methods and materials: Magnetic resonance images (spin-echo techniques; T1-w pre/post gadolinium, T2-w) of 59 patients as part of a multicenter study were evaluated retrospectively. Qualitative image analysis was performed: signal intensity (point of reference extraosseous: muscle, intraosseous: bone marrow), enhancement patterns, lesion delineation and differentiation between tumor and oedema.

Results: Signal intensity: T1-w: extraosseous: 75% isointense, intraosseous: 92% hypointense; T2-w extraosseous: 100% hyperintense, intraosseous: 93% hyperintense. Enhancement pattern: 97% both extra- and intraosseous. Best delineation intraosseous in T1-w (53% good, 36% very good), extraosseous in gadolinium enhanced T1-w (46% good, 37% very good) and T2-w (55% good, 33% very good). Differentiation between tumour and oedema was intraosseous not possible, extraosseous in T2-w in 61%.

Conclusion: Morphology of Ewing sarcoma in magnetic resonance imaging is rather uniform. The lesion is intra- and extraosseous sharply delineated, though tumour and oedema can be rarely differentiated.