56 year old female with history of left buttock abscess status post I&D 2 weeks ago now with increased drainage in the setting of chronic immunosuppression on steroids and a history of total hip replacement with revision (2002, 2012). Assess extent of abscess cavity and possible joint involvement. Evaluation of the hip and surrounding soft tissues is limited due to metallic susceptibility artifact resulting from the patient's total arthroplasty and acetabular reconstruction. There is a nonenhancing collection of heterogeneous signal intensity on T2-weighted images along the medial margin of the left gluteus maximus muscle that extends through the skin best seen on image 33 of series 1102 which presumably represents residua of the patient's known draining buttock abscess perhaps containing packing material. The collection is approximately 4 cm x 1 cm in transverse dimension and 6-7 cm in oblique craniocaudal dimension tracking from the skin towards the ischial tuberosity; however we see no signal abnormality within the ischium to indicate osteomyelitis. There is surrounding soft tissue inflammation involving the skin, subcutaneous fat and the gluteus maximus muscle. This inflammation also extends anteriorly and laterally to involve the quadratus femoris and adductor muscles of the hip but we see no direct communication with the hip joint itself.The conjoined tendon of the hamstrings is avulsed from its origin on the ischial tuberosity and there is a tear of the proximal semimembranosus tendon such that only a few strands are seen extending to the ischium. Edema extends inferiorly along the hamstrings however this may reflect a chronic tear rather than an acute tear.There is bandlike signal abnormality tracking through the subcutaneous fat of the lateral hip region which likely represents a scar related to the patient's prior surgery. There is edema in the adjacent subcutaneous fat. Small collection of near-fluid signal intensity with thin enhancing margins and septa in the soft tissues along the cranial extent of the hardware measuring 2 cm x 1 cm x 3 cm which we suspect likely represents a small seroma, with a small abscess considered less likely. There is atrophy of the left gluteus minimus and medius muscles as well as fatty atrophy of the left iliopsoas muscle.There is a collection of heterogeneous high signal intensity on T2-weighted images along the medial aspect of the proximal femur extending inferiorly off the field of view of the study. It is surrounded by a rim of low signal intensity which corresponds to ossification seen on recent radiographs. We suspect that this finding represents a prior subperiosteal hemorrhage with subsequent bone formation rather than representing an infectious process as it does not appear to communicate with the aforementioned abscess cavity.A few mildly enlarged inguinal lymph nodes are noted on the left. Evaluation of the right hip on the large field-of-view images is limited by metallic susceptibility artifact resulting from the patient's total hip arthroplasty. Note is made of heterotopic ossification along the gluteal tendons. Degenerative arthritis affects the visualized lower lumbar spine.
1.Postoperative changes as described above.2.Draining buttock abscess cavity and surrounding inflammation as described above. We see no evidence to suggest joint involvement.3.Other findings as above.