Table 1 Radiological grading of stress fractures (Arendt et al¹³).

	Radiology	Bone scan		MRI
Normal	Normal	Normal		Normal
Grade 1	Normal	Poorly defined area of increased activity		Positive STIR image
Grade 2	Normal	More intense but still poorly defined		Positive STIR plus positive T2
Grade 3	Discrete line (?), discrete periosteal reaction (?)	Sharply demarked area of increased activity focal or fusiform		Positive T1 and T2 but without definite cortical break
Grade 4	Fracture or periosteal reaction	More intense transcortical localised uptake		Positive T1 and T2 fracture line

MRI, magnetic resonance imaging; STIR, short T1 inversion recovery.