Figure 4a. Focal cartilage contusion in a 17-year-old patient after trauma. (a) Sagittal 3D spoiled GRE image shows a contusion of the medial femoral condyle (arrow). (b) Sagittal fast SE image obtained with fat suppression shows the contusion (solid arrow) and adjacent marrow edema (dashed arrow). Marrow edema is an excellent marker for cartilage damage but is not seen with the relatively T1-weighted spoiled GRE technique.