Ultrasound in Local Soft Tissue Lesions After Orthopaedic Implant Surgery / 中国医学影像学杂志

ABSTRACT

PurposeArtifacts of metal implantation severely affect image quality of CT or MRI examination, which restricts the display of local soft tissue lesions after orthopaedic surgery. This study aims to explore the application value of ultrasound examination in local soft tissue lesions after metal implant surgery.Materials and Methods Seventy patients with metal implantation after various orthopedic surgeries received US examination, and such sonographic features were recorded as lesion morphology, size, internal echo, edge, with/without capsule and calcification, and blood flow. Moreover, the clinical and radiologic data of patients like X-ray, CT and MRI were compared with the US results so as to determine the sensitivity of ultrasonic examination.Results The peripheral nerve injury might lead to thickened swelling and echo reduction. Ultrasonography revealed 20 cases of hematoma formation, 5 cases of abscess, 5 cases of pseudoaneurysm, 3 cases of myositis ossificans, 15 cases of bone tumor recurrence and 12 cases of peripheral nerve injury in operative region. Compared with the clinical results , the sensitivity, specificity and accuracy of ultrasound diagnosis of the study reached 89.4%, 75.0% and 88.6%, respectively, which were signiifcantly higher than those of X-ray, CT and MRI (χ2=78.642, 46.596 and 61.371,P<0.01). The ultrasonic results showed that most hematomas had clear boundary with homogenous echo inside to echo-free zone. Abscesses mostly displayed cystic or hybrid echo with floatable intracavitary pus spots echo, and no blood flow signal existed in the central area of color Doppler. Pseudoaneurysm in the US showed cystic mass around artery, blood flow rotating in capsule, and the typical two-stage bi-spectrum signal in the neck of capsule. Myositis ossiifcans showed intramuscular irregular hyperecho with acoustic shadow. When bone tumor recurred, US showed hypoechoic soft tissue mass with moth-eaten bone destruction, and blood flow signals within the mass were often detected.Conclusion Ultrasonography has relatively high accuracy in observing soft tissues around metal implantation, which can be used as a premier method.