Figure 4.

(A) T1-weighted SEMAC-VAT image, of a 73-year-old male who underwent THA on his right hip joint, showing a low-to-intermediate signal band at the interface between the bone and acetabular cup (black arrow head) (B) T2-weighted TIRM SEMAC-VAT image, of a 73-year-old male who underwent THA on his right hip joint, showing a low signal band surrounding the acetabular cup (white arrow head) (C) T1-weighted SEMAC-VAT image, of a 73-year-old male who underwent THA on his right hip joint, showing an intermediate signal band surrounding the metal implant (white arrow). The lesion on the lesser trochanter side was thinner than 2 mm and could not be diagnosed with bone resorption (D) T2-weighted TIRM SEMAC-VAT image, of a 73-year-old male who underwent THA on his right hip joint, showing a high signal band surrounding the metal implant (black arrows) (E) DR image, of a 73-year-old male who underwent THA on his right hip joint, showing a thin radiolucent line surrounding both the acetabular and femoral components (white arrows). Compared with the SEMAC-VAT MR image, DR underestimated the lesion on the lateral side, and we could hardly tell whether the acetabular radiolucent band in the DR image was caused by bone resorption or osteoporosis. The patient was diagnosed with bone resorption (acetabular zone and lesion on the greater trochanter side) and a synovial-like membrane (lesion on the lesser trochanter side). DR = digital radiography; MR = magnetic resonance; SEMAC-VAT = slice-encoding metal artifact correction and view-angle tilting; THA = total hip arthroplasty; TIRM = turbo inversion recovery magnitude.