Ultrasonogram of osteosarcoma. Ultrasonographic appearance of a thoracic precardial mass in a miniature goat. The mass was round and multicystic and had a diameter of approximately 11 cm. A sector scanner with a phased-array probe and a frequency of 1.9 to 4.0 MHz (octave harmonics) was used. 1 Mass, 2 Cyst, Ds Dorsal, Vt Ventral.