Selected images of the pelvis and left hip.
There is increased signal in the metaphysis of the left proximal femur. This is asymmetrical and abnormal.
In addition, there is linear STIR hyperintensity throughout the same physis. This is subtle and could easily be missed. You need to go looking for it.
Asymmetric physeal and metaphyseal STIR hyperintensity should make you think about slipped upper femoral epiphysis in a skeletally immature patient. In this case, pre-slip.