Advanced ultrasound techniques improve soft tissue tumor evaluation

Shear wave elastography (SWE) and superb microvascular imaging (SMI) can help better evaluate soft tissue tumors, suggest findings published August 25 in Radiology. 

These two approaches, both alone and combined with B-mode ultrasound, could assist in distinguishing benign from nonbenign lesions, wrote a team led by David Macía-Suárez, PhD, MD, from Complexo Hospitalario Universitario de Santiago de Compostela in Spain. 

“Although a definitive management algorithm cannot yet be established, our findings suggest that advanced ultrasound techniques may help prioritize diagnostic and interventional strategies, particularly selection for MRI or biopsy,” the Macía-Suárez team wrote. 

Differentiating benign from malignant soft tissue tumors can be challenging. While ultrasound is the go-to imaging approach to evaluate these lesions, it can struggle with determining which lesions are benign or malignant. 

However, ultrasound technology in recent years has incorporated advanced techniques that can improve diagnostic accuracy. These include elastography, which measures the stiffness of a targeted tumor, and microvascular imaging, which can visualize small vessels and suppress signals from slow-flowing tissues. 

Macía-Suárez and colleagues studied whether these advanced techniques improve diagnostic accuracy for evaluating soft tissue tumors. 

Examples of ultrasound findings and techniques. (A) Images in a 39-year-old male patient with a mass in the left thigh. The mass is heterogeneous on the B-mode US image (compared with the patient in D) and showed increased microvascularity (superb microvascular imaging [SMI]) and shear-wave elastography (SWE) values. Undifferentiated pleomorphic sarcoma was diagnosed at biopsy (with pleomorphic rhabdomyosarcoma in surgical specimen). (B) Images in an 18-year-old male patient with a mass in the left leg. The mass is hypoechoic on the B-mode image, with no other findings suggestive of malignancy. The lesion is in contact with the cortex of the tibia, which is slightly irregular. CT revealed a doubtful anteromedial tibial erosion. The microvascular study demonstrated high vascularization, suggestive of malignancy. Periosteal Ewing sarcoma was diagnosed with both histologic and immunohistochemical confirmation. (C) Images in a 69-year-old female patient with a lump growing on the outside of the left leg. Multiple SWE examinations were performed (please note the high values obtained in the measurements, whereas the color map highlights the stiffness relative to adjacent tissues). SMI showed areas of increased vascularization to target for sampling. Undifferentiated spindle cell sarcoma was diagnosed at biopsy, with residual leiomyosarcoma in the surgical specimen after neoadjuvant therapy. (D) Images in a 56-year-old female patient with a mass in the right thigh. The mass is heterogeneous at both B-mode ultrasound (similar to patient A) and MRI (coronal T2-weighted spectral attenuated inversion recovery [SPAIR]; T1-weighted pre-contrast and postcontrast imaging), which even shows uptake after the administration of paramagnetic contrast material, which is traditionally suggestive of malignancy. Low values at SMI and elastography are suggestive of benignity. Spindle cell lipoma was diagnosed at biopsy, with atypical spindle cell lipomatous tumor in the surgical specimen.RSNA

The study included 167 lesions from 167 patients (mean age, 59.3 years) with soft tissue tumors who were referred for biopsy in 2022 and 2023. The team recorded B-mode ultrasound features, including largest diameter (LD), deepest diameter (DD), DD-to-LD ratio, and SWE and SMI values. 

Nonbenign soft tissue tumors showed higher mean SWE and SMI values compared to benign lesions. The researchers also reported differences in DD and DD-to-LD ratios for benign and nonbenign lesions. 

SMI and SWE achieved area under the curve (AUC) values of 0.82 and 0.75, respectively. SMI also achieved 71% sensitivity and 87% specificity, while SWE achieved 75% sensitivity and 71% specificity, respectively.  

Finally, the team combined LDs and DDs with SWE and SMI, which improved the AUC to 0.87. 

The study authors highlighted that these techniques could be incorporated into future guidelines and scoring systems. 

“Further studies are needed to refine parameter combinations, validate these results, and support standardized clinical guidelines,” they added. 

These ultrasound techniques could help increase diagnostic confidence and inform treatment decisions, according to an accompanying editorial written by Kenneth Lee, MD, from the University of Wisconsin in Madison, and Zachary Stewart, MD, from Mass General Brigham in Boston. 

“A multiparametric model combining SWE and SMI establishes a quantitative foundation for objective ultrasound assessments that are likely to extend well beyond soft tissue tumors,” they wrote. 

The editorial authors added that future opportunities “should address challenges with implementation and adoption.” This “especially” goes for different vendor platforms, so that standardization and scoring of soft tissue tumors can be established. 

Read the full study here.