Asymmetric fatty marrow of right petrous apex.

Asymmetric pneumatization is related to another normal variation: asymmetric fatty marrow within the petrous apex. This finding is a common incidental finding on brain, skull base, and soft-tissue neck MRI studies obtained for evaluation of nonotologic complaints. Typically, normal marrow contains significant adipose tissue, and signal characteristics parallel those of scalp or orbital fat. Fatty marrow is hyperintense on routine T1- and T2-weighted sequences. (1)