Indicator of Small Calcification Detection in Ultrasonography using Decorrelation of Forward Scattered Waves

Abstract

For the improvement of the ability in detecting small calcifications using Ultrasonography (US) we propose a novel indicator of calcifications in an ultrasound B-mode image without decrease in frame rate. Since the waveform of an ultrasound pulse changes at a calcification position, the decorrelation of adjacent scan lines occurs behind a calcification. Therefore, we employ the decorrelation of adjacent scan lines as an indicator of a calcification. The proposed indicator depicted wires 0.05 mm in diameter at 2 cm depth with a sensitivity of 86.7% and a specificity of 100%, which were hardly detected in ultrasound B-mode images. This study shows the potential of the proposed indicator to approximate the detectable calcification size using an US device to that of an X-ray imager, implying the possibility that an US device will become a convenient, safe, and principal clinical tool for the screening of breast cancer. Keywords—Ultrasonography, Calcification, Decorrelation, Forward scattered wave we reported that the waveform change of the echo caused by a calcification results in the decorrelation between the echoes received at adjacent scan lines (7), (8). These reports indicate that the existence of a small calcification is predictable from the waveform difference between adjacent scan lines by calculating cross-correlation coefficients. In this paper, we propose a novel indicator of calcifications and evaluate the method experimentally using a commercial US device.