Fig. 11
From: Pelvic heterotopic ossification: when CT comes to the aid of MR imaging
A 34-year-old paraplegic male following spinal cord injury. Examinations were performed to evaluate abscess and osteomyelitis of the left ischial tuberosity (large arrow). The MR study reveals a lesion in the area of the right psoas muscle (small arrow): (a) central hypo-intense area on axial T1-weighted non-enhanced image (small arrow), (b) enhanced tissue and some fluid after contrast administration (small arrow). Note that the sterile HO is similar to the abscess of the left ischial region. c The corresponding CT shows the mass as non-homogeneous with some subtle calcifications on the medial side. d The CT study repeated 10 months later shows transformation of the immature bone into a mature, heterotopic ossification that adheres to the femur