Microcalcifications as elastic scatterers under ultrasound

One of the fundamental limitations of medical ultrasound in the imaging of the breast is the inability of current practice to reliably visualize microcalcifications in the size range of clinical interest. Microcalcifications (MCs) are small crystals of calcium phosphates that form in human tissue through a number of mechanisms. The size, morphology, and distribution of MCs are important indicators in the mammographic screening for and diagnosis of various carcinomas in the breast. We are investigating the imaging of MCs under ultrasound in the interest of extending the utility of medical ultrasound in the breast clinic. We present an analysis of the acoustic properties of MCs modeled as elastic spheres based on the Faran model that considers the predicted complex spectra and spatial coherence of echoes from MCs. We have found the predictions of the model to be similar to ultrasound echoes from suspected MCs in vivo. We also present breast phase aberration estimates and spatial and frequency compounding results based on the echoes from these targets.