Lee Christine, Zhou Chenyun, Hyde Brenda, Song Pengfei, Hangiandreou Nicholas
Department of Radiology, Division of Breast Imaging and Intervention, Mayo Clinic, Rochester, China.
Department of Ultrasound, West China Hospital of Sichuan University, Chengdu, Sichuan, China.
J Clin Imaging Sci. 2020 Apr 18;10:21. doi: 10.25259/JCIS_9_2020. eCollection 2020.
Biopsy markers are often placed into biopsy-proven metastatic axillary lymph nodes to ensure later accurate node excision. Ultrasound is the preferred imaging modality in the axilla. However, sonographic identification of biopsy markers after neoadjuvant therapy can be challenging. This is due to poor conspicuity relative to surrounding parenchymal interfaces, treatment-related alteration of malignant morphology during neoadjuvant chemotherapy, or extrusion of the marker from the target. To the authors' knowledge, the literature provides no recommendations for ultrasound scanning parameters that improve the detection of biopsy markers. The purpose of this manuscript is 3-fold: (1) To determine scanning parameters that improve sonographic conspicuity of biopsy markers in a phantom and cadaver model; (2) to implement these scanning parameters in the clinical setting; and (3) to provide strategies that might increase the likelihood of successful ultrasound detection of biopsy markers in breast imaging practices.
An study was performed using a phantom designed to simulate the heterogeneity of normal mammary or axillary soft tissues. A selection of available biopsy markers was deployed into this phantom and ultrasound (GE LOGIQ E9) was performed. Scanning parameters were adjusted to optimize marker conspicuity. For the cadaver study, the biopsy markers were deployed using ultrasound guidance into axillary lymph nodes of a female cadaver. Adjustments in transducer frequency, dynamic range, cross-beam (spatial compound imaging), beam steering, speckle reduction imaging, harmonic imaging, colorization, and speed of sound were evaluated. Settings that improved marker detection were used clinically for a year.
Sonographic scanning settings that improved biopsy marker conspicuity included increasing transducer frequency, decreasing dynamic range, setting cross-beam to medium hybrid, turning on beam steering, and setting speckle reduction imaging in the mid-range. There was no appreciable improvement with harmonic imaging, colorization, or speed of sound.
On a currently available clinical ultrasound scanning system, ultrasound scanning parameters can be adjusted to improve the conspicuity of biopsy markers. Overall, optimization requires a balance between techniques that clinically increase contrast (dynamic range, harmonic imaging, and steering) and those that minimize graininess (spatial compound imaging, speckle reduction imaging, and steering). Additional scanning and procedural strategies have been provided to improve the confidence of sonographic detection of biopsy markers closely associated with the intended target.
活检标记物常被放置在经活检证实的转移性腋窝淋巴结中，以确保后续准确切除淋巴结。超声是腋窝首选的成像方式。然而，新辅助治疗后超声识别活检标记物可能具有挑战性。这是由于相对于周围实质界面的显影不佳、新辅助化疗期间恶性形态的治疗相关改变或标记物从靶部位挤出。据作者所知，文献中没有关于改善活检标记物检测的超声扫描参数的建议。本手稿的目的有三个：（1）确定能提高模型和尸体模型中活检标记物超声显影性的扫描参数；（2）在临床环境中应用这些扫描参数；（3）提供可能增加乳腺成像实践中超声成功检测活检标记物可能性的策略。
使用一个设计用于模拟正常乳腺或腋窝软组织异质性的模型进行研究。将多种可用的活检标记物放置到该模型中并进行超声检查（GE LOGIQ E9）。调整扫描参数以优化标记物的显影性。对于尸体研究，在超声引导下将活检标记物放置到一名女性尸体的腋窝淋巴结中。评估了换能器频率、动态范围、交叉波束（空间复合成像）、波束控制、斑点减少成像、谐波成像、彩色化和声速的调整。改善标记物检测的设置在临床中使用了一年。
提高活检标记物显影性的超声扫描设置包括提高换能器频率、降低动态范围、将交叉波束设置为中等混合、开启波束控制以及将斑点减少成像设置在中等范围。谐波成像、彩色化和声速方面没有明显改善。
在当前可用的临床超声扫描系统上，可以调整超声扫描参数以提高活检标记物的显影性。总体而言，优化需要在临床上增加对比度的技术（动态范围、谐波成像和波束控制）与使颗粒度最小化的技术（空间复合成像、斑点减少成像和波束控制）之间取得平衡。还提供了额外的扫描和操作策略，以提高与预期靶标紧密相关的活检标记物超声检测的可信度。
