Role of Ultrasonography in Imaging of Tumours Around Knee Joint

摘要

Imaging of the neoplasms of knee is important for multidisciplinary management in the modern day practice. Radiography followed by Magnetic Resonance Imaging (MRI) is a commonly used modality, whereas Ultrasonography (USG) is less commonly used method for this purpose, especially for bone tumours.Aim: To evaluate the role of USG in tumours around knee joint.Materials and Methods: This was a prospective descriptive study carried out in Nizam?s institute of Medical Sciences, Hyderabad, India from January 2015 to June 2017. During the study period, 158 patients presented to the orthopaedic department with complaints of swelling of knee were included. Based on clinical history of trauma, joint pain, fever, swelling of knee, restricted movements of knee and clinical examination of affected knee with radiography, 58 patients with 59 lesions were included. USG and cross-sectional imaging (CT/MRI) were done in all patients. Final diagnosis was made by histopathological findings or classical imaging features. Non parametric Mann-Whitney-Wilcoxon test was used to differentiate the resistive indices of benign and malignant lesions.Results: Study group consisted of 59 lesions where 77.97% (46/59) were bone lesions and 22.03 % (13/59) were soft tissue lesions. USG is 100% sensitive to demonstrate cortical thinning/break/fracture, soft tissue component, Neurovascular Bundle (NVB) involvement, cystic component with fluid-fluid level and joint effusion. USG is better than CT for assessing the cartilage cap of osteochondroma; USG is better than MRI and comparable to CT to identify the calcifications; Doppler USG had 89.5% sensitivity and 80% specificity to differentiate benign and malignant lesions, although only 61% lesions (36/59) showed vascularity; Doppler along with gray scale parameters (like peritumoural oedema, necrosis, absent fat rim, size and heterogeneity of soft tissue component in bone lesions, invasion of adjacent joint, muscles, NVB and lymph node involvement) was helpful in 88.1% (52/59) for diagnosing as well as differentiating benign from malignant lesions.Conclusion: USG is useful in all soft tissue tumours and bone tumours with cortical discontinuity, whereas less informative in intra-osseous and sclerotic lesions. It is useful to differentiate benign and malignant lesions. It is very informative than any other modality in recurrent tumours with implants producing artefacts.