Tumor characterization and treatment monitoring of postsurgical human breast specimens using harmonic motion imaging (HMI).

Yang Han,Elisa Konofagou,Hanina Hibshoosh,Shutao Wang,Bret Taback

doi:10.1186/s13058-016-0707-3

Abstract

BackgroundHigh-intensity focused ultrasound (HIFU) is a noninvasive technique used in the treatment of early-stage breast cancer and benign tumors. To facilitate its translation to the clinic, there is a need for a simple, cost-effective device that can reliably monitor HIFU treatment. We have developed harmonic motion imaging (HMI), which can be used seamlessly in conjunction with HIFU for tumor ablation monitoring, namely harmonic motion imaging for focused ultrasound (HMIFU). The overall objective of this study was to develop an all ultrasound-based system for real-time imaging and ablation monitoring in the human breast in vivo.MethodsHMI was performed in 36 specimens (19 normal, 15 invasive ductal carcinomas, and 2 fibroadenomas) immediately after surgical removal. The specimens were securely embedded in a tissue-mimicking agar gel matrix and submerged in degassed phosphate-buffered saline to mimic in vivo environment. The HMI setup consisted of a HIFU transducer confocally aligned with an imaging transducer to induce an oscillatory radiation force and estimate the resulting displacement.Results3D HMI displacement maps were reconstructed to represent the relative tissue stiffness in 3D. The average peak-to-peak displacement was found to be significantly different (p = 0.003) between normal breast tissue and invasive ductal carcinoma. There were also significant differences before and after HMIFU ablation in both the normal (53.84 % decrease) and invasive ductal carcinoma (44.69 % decrease) specimens.ConclusionsHMI can be used to map and differentiate relative stiffness in postsurgical normal and pathological breast tissues. HMIFU can also successfully monitor thermal ablations in normal and pathological human breast specimens. This HMI technique may lead to a new clinical tool for breast tumor imaging and HIFU treatment monitoring.

Highlights

High-intensity focused ultrasound (HIFU) is a noninvasive technique used in the treatment of early-stage breast cancer and benign tumors
harmonic motion imaging (HMI) In Fig. 2, 3D HMI images of a normal breast specimen, a breast tumor specimen, and an FA specimen before and after harmonic motion imaging for focused ultrasound (HMIFU) ablation are shown in comparison with gross pathology images
In the 1D system, the HMI displacement amplitudes of the normal breast, invasive ductal carcinoma (IDC), and FA tissue averaged within the −3 dB regions were 40.10 ± 15.50 μm (n = 9), 24.90 ± 9.64 μm (n = 5), and 7.40 μm (n = 1), respectively (Fig. 3a)

Summary

Introduction

High-intensity focused ultrasound (HIFU) is a noninvasive technique used in the treatment of early-stage breast cancer and benign tumors. We have developed harmonic motion imaging (HMI), which can be used seamlessly in conjunction with HIFU for tumor ablation monitoring, namely harmonic motion imaging for focused ultrasound (HMIFU). Breast cancer is the most common cancer and the second leading cause of cancer death among women. HIFU is an entirely noninvasive technique, in which the ultrasound beam is focused on a small target volume to reach high focal power, resulting in temperature elevations causing coagulative necrosis in the target while surrounding structures are spared. Acoustic energy can induce temperature elevations at the focal spot in a few seconds and can simultaneously induce cell death and vascular destruction in normal and tumor tissues [5]. Because of the steep thermal gradients involved, the boundaries of the ultrasound-treated volumes can be closely spaced until the entire target is covered

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Conclusion