Hendriks Gijs A G M, Holländer Branislav, Menssen Jan, Milkowski Andy, Hansen Hendrik H G, de Korte Chris L
Medical UltraSound Imaging Center (MUSIC), Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, The Netherlands.
Phys Med Biol. 2016 Apr 7;61(7):2665-79. doi: 10.1088/0031-9155/61/7/2665. Epub 2016 Mar 15.
In breast cancer screening, the automated breast volume scanner (ABVS) was introduced as an alternative for mammography since the latter technique is less suitable for women with dense breasts. Although clinical studies show promising results, clinicians report two disadvantages: long acquisition times (>90 s) introducing breathing artefacts, and high recall rates due to detection of many small lesions of uncertain malignant potential. Technical improvements for faster image acquisition and better discrimination between benign and malignant lesions are thus required. Therefore, the aim of this study was to investigate if 3D ultrasound elastography using plane-wave imaging is feasible. Strain images of a breast elastography phantom were acquired by an ABVS-mimicking device that allowed axial and elevational movement of the attached transducer. Pre- and post-deformation volumes were acquired with different constant speeds (between 1.25 and 40.0 mm s(-1)) and by three protocols: Go-Go (pre- and post-volumes with identical start and end positions), Go-Return (similar to Go-Go with opposite scanning directions) and Control (pre- and post-volumes acquired per position, this protocol can be seen as reference). Afterwards, 2D and 3D cross-correlation and strain algorithms were applied to the acquired volumes and the results were compared. The Go-Go protocol was shown to be superior with better strain image quality (CNRe and SNRe) than Go-Return and to be similar as Control. This can be attributed to applying opposite mechanical forces to the phantom during the Go-Return protocol, leading to out-of-plane motion. This motion was partly compensated by using 3D cross-correlation. However, the quality was still inferior to Go-Go. Since these results were obtained in a phantom study with controlled deformations, the effect of possible uncontrolled in vivo tissue motion artefacts has to be addressed in future studies. In conclusion, it seems feasible to implement 3D ultrasound quasi-static elastography on an ABVS-like system and to reduce scan times within one breath-hold (~10 s) by plane-wave acquisitions.
在乳腺癌筛查中，自动乳腺容积扫描仪（ABVS）作为乳腺X线摄影的替代方法被引入，因为后一种技术不太适合乳房致密的女性。尽管临床研究显示出有前景的结果，但临床医生报告了两个缺点：采集时间长（>90秒）会引入呼吸伪影，以及由于检测到许多恶性潜能不确定的小病变而导致召回率高。因此，需要进行技术改进以实现更快的图像采集以及更好地区分良性和恶性病变。因此，本研究的目的是探讨使用平面波成像的三维超声弹性成像是否可行。通过一个模拟ABVS的设备获取乳腺弹性成像体模的应变图像，该设备允许附着的换能器进行轴向和仰角移动。以不同的恒定速度（1.25至40.0毫米/秒之间）并通过三种方案获取变形前和变形后的容积：Go-Go（变形前和变形后的容积具有相同的起始和结束位置）、Go-Return（类似于Go-Go，但扫描方向相反）和Control（每个位置采集变形前和变形后的容积，该方案可视为参考）。之后，将二维和三维互相关算法及应变算法应用于获取的容积，并比较结果。结果表明，Go-Go方案具有更好的应变图像质量（CNRe和SNRe），优于Go-Return方案，且与Control方案相似。这可归因于在Go-Return方案中对体模施加了相反的机械力，导致平面外运动。通过使用三维互相关，这种运动得到了部分补偿。然而，质量仍低于Go-Go方案。由于这些结果是在具有可控变形的体模研究中获得的，未来的研究必须解决体内组织可能出现的不可控运动伪影的影响。总之，在类似ABVS的系统上实施三维超声准静态弹性成像并通过平面波采集在一次屏气（约10秒）内减少扫描时间似乎是可行的。
