Perfusion pattern of musculoskeletal masses using contrast-enhanced ultrasound: a helpful tool for characterisation?

We report 54 patients with histologically evaluated musculoskeletal masses who underwent grey-scale and contrast-enhanced ultrasound (CEUS), followed by ultrasound-guided biopsy. We hypothesise that the definition of a CEUS-based enhancement pattern improves the characterisation of tumour malignancy.

Fifty-four patients with soft-tissue masses were examined according to our standardised ultrasound procedure. After CEUS, quantitative and qualitative perfusion analyses were performed and each mass was assigned to one of four preliminarily defined perfusion patterns (P1-P4). Additionally, mass size and localisation were recorded. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) in the definition of malignancy were calculated for relevant combinations of localisation, size and perfusion pattern.

The single event probability for malignancy was 0% for the P1 and P4 perfusion patterns, and 60% for P2 and 80% for P3. The best combined sensitivity (89%) and specificity (85%) was achieved in a "three-feature combination" of size >3.3 cm, mass location below the superficial fascia and either P2 or P3 perfusion pattern with a PPV of 86% and NPV of 88%.

The proposed definition of perfusion pattern types with CEUS may serve as a new and reliable diagnostic tool for distinguishing malignant soft-tissue masses from their benign counterparts.

• CEUS can assess "tumour perfusion". • Four typical perfusion patterns are seen on CEUS of musculoskeletal masses. • Knowledge of tumour size, localisation and perfusion pattern can help patient management.