Visualization of microvasculature with contrast-enhanced ultrasound in the diagnosis of soft tissue tumors

Introduction. Ultrasound (US) is the first step in diagnosing soft tissue tumors (STT). However, standard US might not provide enough information to determine the nature of STT, particularly for rare or deep tumors. Malignant tumors are characterized by new blood vessel growth (neoangiogenesis), so technologies that can detect microcirculation and blood flow are crucial for diagnosing them. One of these technologies is contrast-enhanced ultrasound (CEUS). CEUS allows us to visualize the smallest blood vessels and evaluate their structure, making it a promising method for diagnosing changes in soft tissues. However, currently, there are no Russian studies published that explore its effectiveness. Objective. To determine the diagnostic effectiveness of CEUS in differentiating between benign and malignant STT and to compare its results with a study without contrast. Materials and methods. This retrospective study examined the results of scans from patients with STT who underwent multiparametric ultrasound examinations (mpUS). The mpUS used standard modes (Bmode, color Doppler mapping, sonoelastography) and contrast-enhanced ultrasound (CEUS). A crucial requirement was the availability of the pathology report, which acted as a reference standard. Results. Based on the results of the analysis of visualization and histological examination data, differential diagnostics of benign and malignant SST was performed; ultrasound without contrast enhancement (CE) had a sensitivity of 82% (CI 69–91 %), specificity of 61 % (CI 48–73 %), accuracy of 70 % (CI 61–78 %), positive predictive value of 63 % (CI 50–75 %), negative predictive value of 80 % (CI 66–90 %), and the area under the curve was 0.72 (good quality of the model). Adding the information obtained with CEUS significantly increased all the parameters: sensitivity – 94 % (CI 83–98%), specificity – 88 % (CI 78–95 %), accuracy – 91 % (CI 84–95%), positive predictive value – 87 % (CI 75–94 %), negative predictive value – 94 % (CI 85–98 %), and area under the curve – 0.91 (excellent quality of the model). Conclusions. The study revealed that ultrasound using only standard modes was significantly less accurate than CEUS. CEUS demonstrated a much higher ability to differentiate between benign and malignant STT. This makes CEUS a valuable tool for diagnosticians and oncologists. However, further research is needed to better understand the potential of CEUS and incorporate it into the diagnostic process for detecting soft tissue lesions, as well as in the program of control observations of the scar area after excision of sarcoma.

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