Breast Cancer Assessment With Pulse-Echo Speed of Sound Ultrasound From Intrinsic Tissue Reflections

Abstract

The aim of this study was to differentiate malignant and benign solid breast lesions with a novel ultrasound (US) technique, which measures speed of sound (SoS) using standard US transducers and intrinsic tissue reflections and scattering (speckles) as internal reference. MATERIALS AND METHODS This prospective, institutional review board-approved, Health Insurance Portability and Accountability Act-compliant prospective comparison study was performed with prior written informed consent from 20 women. Ten women with histological proven breast cancer and 10 with fibroadenoma were measured. A conventional US system with a linear probe was used for SoS-US (SonixTouch; Ultrasonix, Richmond, British Columbia, Canada). Tissue speckle reflections served as a timing reference for the US signals transmitted through the breasts. Relative phase inconsistencies were detected using plane wave measurements from different angular directions, and SoS images with 0.5-mm resolution were generated using a spatial domain reconstruction algorithm. The SoS of tumors were compared with the breast density of a larger cohort of 106 healthy women. RESULTS Breast lesions show focal increments ΔSoS (meters per second) with respect to the tissue background. Peak ΔSoS values were evaluated. Breast carcinoma showed significantly higher ΔSoS than fibroadenomas ([INCREMENT]SoS > 41.64 m/s: sensitivity, 90%; specificity, 80%; area under curve, 0.910) and healthy breast tissue of different densities (area under curve, 0.938; sensitivity, 90%; specificity, 96.5%). The lesion localization in SoS-US images was consistent with B-mode imaging and repeated SoS-US measurements were reproducible. CONCLUSIONS Using SoS-US, based on conventional US and tissue speckles as timing reference, breast carcinoma showed significantly higher SoS values than fibroadenoma and healthy breast tissue of different densities. The SoS presents a promising technique for differentiating solid breast lesions.

Ultrasound Aberration Correction based on Local Speed-of-Sound Map Estimation

“…The assumption of a global homogeneous SoS in beamforming led in this case to a 2-to-3 times higher localization error. In this study, the largest SoS contrast was 3% (45 m/a), which is on the order of maximum variations expected in the breast [11]. Nevertheless, higher SoS contrasts, e.g.…”

Speed-of-sound imaging using diverging waves

“…Similarly, when an inclusion is located to the sides (e.g., simulation 27), many Tx apertures may not cover it, again reducing lag measurements for its reconstruction. Accordingly, where possible, an inclusion should be imaged in the middle of the imaging field for optimal reconstructions [27,31]. For the PW cases, the best reconstructions are achieved using an angle accumulation of Δθ = 2 • and an adapted receive aperture, similarly to [34].…”

“…Note that for PW we focus on the center part of the image and mask out 10% on both sides of the imaging region (Fig. 5), since the apodization of the angled PW causes significant artifacts in these image regions, as was also discussed in [27]. Accordingly, RMSE and CNR were computed in these shown central regions.…”

“…for breast tissue classification [17], solid mass differentiation [13], and imaging human-knee [41]. Using conventional transducers in pulse-echo mode, SoS has been studied clinically for quantifying muscle loss [30] and breast density [29], as well as for differential diagnosis of breast can-cer [27]. SoS maps can also help to correct for beamforming delays and hence to improve any other US imaging modality.…”

Hybrid Spectral-IRDx: Near-IR and Ultrasound Attenuation System for Differentiating Breast Cancer From Adjacent Normal Tissue

“…However, such systems needs to be designed and developed to perform a similar analysis for ex-vivo breast biopsy tissues. High-frequency time-resolved ultrasound techniques have also been studied to diagnose cancer [13], [14]. Anastasiadis [13] reviewed high-frequency time-resolved ultrasound techniques to diagnose cancer.…”