Fig. 1.

Osteosarcoma of the proximal tibial metaphysis with extension to physis, epiphysis and joint surface in a 9.5-year-old boy (patient 17). a−f Coronal planes acquired at T1-W (a, d), DWI at b0 value (b, e) and corresponding apparent diffusion coefficient (ADC) maps (c, f). Examples of ADC calculation (good responder) at MRI-1 (a, b, c) and MRI-2 (d, e, f): a region of interest is manually drawn around the tumour along its longer axis to calculate the mean ADC of the tumour. A qualitative assessment of the ADC map shows a decrease in signal intensity at mid-course chemotherapy