Mitchell classification of osteonecrosis of the femoral head

The Mitchell classification is used to stage osteonecrosis of the femoral head and is based on MRI signal characteristics within the center of the lesion on T1 and T2-weighted images.

Classification

The lesion is classified into four stages with stage A representing early disease and stage D representing late disease. However, the signal intensity of more than one stage can be found in a single lesion.

• stage A

  • T1: hyperintense

  • T2: intermediate

  • signal analogous to that of fat

• stage B

  • T1: hyperintense

  • T2: hyperintense

  • signal analogous to that of subacute blood

• stage C

  • T1: hypointense

  • T2: hyperintense

  • signal analogous to that of fluid/edema

• stage D

  • T1: hypointense

  • T2: hypointense

  • signal analogous to that of fibrosis

History and etymology

This classification was described by D G Mitchell et al. in 1987 ¹.

See also

• osteonecrosis

  • osteonecrosis of the femoral head

    • Ficat and Arlet classification

    • ARCO classification

    • Steinberg staging