Table 2.

Tibial Stress Injury (TSI) Image Grading Criteria (This table was published Radiology, 263, Beck BR, Bergman AG, Miner M, Arendt EA, Klevansky AB, Matheson GO, Norling TL, Marcus R: Tibial stress injury: Relationship of radiographic, nuclear medicine bone scanning, MR imaging, and CT Severity grades to clinical severity and time to healing, 811–818, Copyright Elsevier, 2012. [5]).

Grade	Radiography [132]	NM Bone Scanning [131]	MR Imaging [2]	CT Scanning [127]
0	No abnormality	No abnormality	No abnormality	No abnormality
I	Gray cortex sign; margin is indistinct, density lower	Linear increased activity in cortical region	Mild to moderate periosteal oedema	Soft tissue mass adjacent to periosteal surface
II	Acute periosteal reaction, density differs from rest of cortex showing incomplete mineralisation	Small focal region of increased activity	Periosteal oedema and bone marrow edema only on T2 weighted images	Increased attenuation of yellow marrow
III	Lucent areas in cortex, ill- defined foci at site of pain	-	Marrow oedema on T1- and T2-weighted images with or without periosteal oedema on T1- or T2- weighted images and loss of cortical signal void, intracortical increased intensity and intracortical linear hyperintensity	Increased hypoattenuation (osteopenia), intracortical hypoattenuation (resorption cavity), and subtle intracortical linear hypoattenuation (striation)
IV	Fracture line present	Very large focal region of highly increased activity	Low-signal-intensity fracture line with all sequences, moderate to severe periosteal oedema on T1- and T-2 weighted images, marrow oedema on T1- and T2- weighted images, may also show severe periosteal and moderate muscle oedema	Hypoattenuating line