Perrey C, Braeker G, Bojara W, Lindstaedt M, Holt S, Ermert H
Institute of High Frequency Engineering, Ruhr University Bochum, Germany.
Biomed Tech (Berl). 2003 May;48(5):135-40. doi: 10.1515/bmte.2003.48.5.135.
Intravascular Ultrasound (IVUS) is routinely used in interventional cardiology for imaging coronary plaque morphology. However, the use of B-mode images for tissue characterization and detection of vulnerable coronary plaques is limited. Strain imaging with ultrasound is a new modality that provides additional information for tissue characterization by imaging differences in tissue stiffness. The aim is to differentiate between vulnerable (soft) plaques and less dangerous calcified (hard) plaques. In this work, the applicability of a time efficient strain imaging algorithm in conjunction with data from IVUS array transducers is evaluated. Unfocused radiofrequency (rf) data from the transducer array is acquired using custom made hardware. Rf line reconstruction is performed offline by synthetic aperture focusing techniques. Vessel mimicking phantoms of different geometries and material stiffness are made from agar and Polyvinyl Alcohol Cryogel (PVA). Experiments are conducted in a water tank and a water column is used for applying intraluminal pressure differences required for strain imaging. The results show that strain images can be calculated with A-lines reconstructed from unfocused rf raw data. Regions of different stiffness can be identified qualitatively by local strain variations. With the used algorithm strains of up to 2% can be imaged without significant decor-relation.
血管内超声（IVUS）在介入心脏病学中常用于冠状动脉斑块形态成像。然而，利用B模式图像进行组织特征分析和检测易损冠状动脉斑块存在局限性。超声应变成像是一种新的模式，通过对组织硬度差异成像为组织特征分析提供额外信息。目的是区分易损（软）斑块和危险性较低的钙化（硬）斑块。在这项工作中，评估了一种高效应变成像算法与IVUS阵列换能器数据结合的适用性。使用定制硬件采集来自换能器阵列的未聚焦射频（rf）数据。通过合成孔径聚焦技术离线进行rf线重建。不同几何形状和材料硬度的血管模拟体模由琼脂和聚乙烯醇冷冻凝胶（PVA）制成。实验在水箱中进行，使用水柱施加应变成像所需的腔内压力差。结果表明，可以从未聚焦的rf原始数据重建的A线计算应变图像。不同硬度区域可通过局部应变变化进行定性识别。使用所采用的算法，可以成像高达2%的应变而无明显去相关。
