Mitchell classification of avascular necrosis

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Mitchell classification of avascular necrosis 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 .

See also