Figure 4b: (a) Coronal T1-weighted spin-echo (340/15) and (b) fat-saturated T2-weighted spin-echo (2000/80) MR images of two knees in a 54-year-old man. Diffuse low signal intensity on T1-weighted images and intermediate signal intensity on T2-weighted images are visible in diaphysis and metaphysis of distal femora and proximal tibiae. The fatty marrow of the subchondral bone is preserved with well-defined margins (arrows).