B-Flow and Contrast-Enhanced Ultrasound (CEUS) Features of Subcutaneous Masses and Nodular Lesions in Dogs

Subcutaneous lesions in dogs are common in clinical practice. This prospective clinical study aims to compare B-flow and CEUS for the characterization of subcutaneous lesions evaluating their usefulness to distinguish benign subcutaneous lesions from malignant ones. Dogs were enrolled and ultrasound cine-loops were achieved in B-mode, Colour Doppler, Power Doppler, B-flow and CEUS. Lesions vascularisation highlighted through B-flow and CEUS were classified into five patterns: P1, absence of contrast uptake; P2, enhancement only in the peripheral area of the lesion; P3, thin (<2 mm) and few vessels (<5/field); P4, thicker (>2 mm) and more numerous vessels (>5/field); P5 enhancement with a reticular aspect and both thick and thin bands inside. Patterns highlighted with B-flow and CEUS were compared to a histological diagnosis of subcutaneous lesions. A total of 24 dogs and 30 subcutaneous nodules were included and divided into three groups: 3 non-neoplastic, 16 benign tumours and 11 malignant tumours. There was a statistically significant difference for B-flow and CEUS to differentiate benign tumours from malignant tumours. B-flow and CEUS had an excellent agreement. B-flow and CEUS displayed similar ability to evaluate different patterns and could be helpful in the evaluation of subcutaneous nodules.