Differentiation and characterization of rat mammary fibroadenomas and 4T1 mouse carcinomas using quantitative ultrasound imaging.

Scatterer properties like the average effective scatterer diameter and acoustic concentration were determined in vivo using a quantitative ultrasound (QUS) technique from two tumor phenotypes grown in animal models. These tumor models included spontaneously occurring mammary fibroadenomas in rats and transplanted 4T1 mammary carcinomas in mice. The scatterer properties of average scatterer diameter and acoustic concentration were estimated using a Gaussian form factor from the backscattered ultrasound measured from both types of tumors. QUS images of the tumors were constructed utilizing estimated scatterer properties from regions in the tumors. The QUS images showed a clear distinction between the two types of tumors and a statistically significant difference existed between their estimated scatterer properties. The average scatterer diameter and acoustic concentration for the mammary fibroadenomas were estimated to be 105 +/- 25 microm and -15.6 +/- 5 dB(mm(-3)), respectively. The average scatterer diameter and acoustic concentration for the carcinomas was estimated to be 28 +/- 4.6 microm and 10.6 +/- 6.9 dB(mm(-3)), respectively. The distinctions in the scattering properties are clearly seen in the QUS images of the tumors and indicate that QUS imaging can be useful in differentiating between different types of mammary tumors.