Breast ultrasound imaging systems performance evaluation using novel Contrast-Detail (C-D) and Anechoic-Target (A-T) phantoms.

Abstract

Ultrasound imaging plays an important role in the early detection and management of breast cancer. This study aimed to evaluate the imaging performance of a range of clinically-used breast ultrasound systems using a set of novel spherical lesion contrast-detail (C-D) and anechoic-target (A-T) phantoms.

Methods: C-D and A-T phantoms were imaged using a range of clinical breast ultrasound systems and imaging modes. A novel sensitive imaging performance metric, the Detectability Score (DS), was proposed which encompasses the Lesion Contrast to Noise Ratio (L_CNR) weighted by the lesion depth and diameter. A geometry-based theoretical model comparing L_CNR measured using spherical and cylindrical phantom anechoic/lesion targets was developed to investigate the influence of slice thickness on focal lesion detectability.

Results: L_CNR and DS metrics derived from phantom image measurments were capable of differentiating the imaging performance of a range of ultrasound systems and advanced imaging modes, with the -2 dB contrast lesion targets offered as the most challenging to resolve. The geometry-based theoretical model, validated against phantom measurements, demonstrated the significant influence of slice thickness on focal lesion detectability, highlighting the need for increased availability of low contrast resolution spherical target phantoms for clinically realistic performance evaluation.

Conclusions: The performance metrics coupled with the -1 dB contrast targets provide scope for evaluating future technological improvements in ultrasound systems. Given the high dependence of breast cancer care on high quality ultrasound imaging techniques, there is a need for evaluating imaging performance using clinically relevant test objects.