MAGNETIC-RESONANCE-IMAGING OF EWING SARCOMA - MORPHOLOGY AND TUMOR DELINEATION

Purpose: The morphology and delineation of Ewing sarcoma in magnetic resonance imaging was investigated. Methods and materials: Magnetic resonance images (spin-echo techniques; T-1-w pre/post gadolinium, T-2-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: T-1-w: extraosseous: 75% isointense, intraosseous: 92% hypointense; T-2-W extraosseous: 100% hyperintense, intraosseous: 93% hyperintense. Enhancement pattern: 97% both extra- and intraosseous. Best delineation intraosseous in T-1-w (53% good, 36% very good), extraosseous in gadolinium enhanced T-1-w (46% good, 37% very good) and T-1-w (55% good, 33% very good). Differentiation between tumour and oedema was intraosseous not possible, extraosseous in T-2-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.