A rotary scanning method to evaluate grooves and porosity for nerve guide conduits based on ultrasound microscopy.
A rotary scanning method to evaluate grooves and porosity for nerve guide conduits based on ultrasound microscopy.
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DOI：
10.1063/1.5004783
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发表时间：
2018-07
期刊：
影响因子：
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通讯作者：
Xiaoyu Yang;Anyu Sun;Bingfeng Ju;Shaoning Xu
中科院分区：
文献类型：
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作者：
Xiaoyu Yang;Anyu Sun;Bingfeng Ju;Shaoning Xu
沟状神经导管在周围神经损伤的临床治疗中具有较好的效果。它们通常是由微结构喷丝板采用纺丝工艺制成的，这很容易造成各种孔隙和形态偏差。内部凹槽的形貌和孔隙度对治疗效果有很大影响。传统的光学或扫描电子显微镜（SEM）方法可以对凹槽进行成像；然而，这些方法是破坏性的，并且需要切片NGCs来制备适合成像的标本。此外，为了确保体外实验和临床研究的可靠结果，需要进行长时间的实验和大量的NGCs。本文提出了一种利用超声成像结合旋转扫描和图像分析算法对NGCs的沟槽和孔隙度进行无损评价的方法。采用两种超声方法：25 mhz点聚焦超声换能器用于观察管道轴向截面，100 mhz点聚焦超声换能器用于检测缺陷引起的大孔隙。在此基础上，提出了一种基于密度的管道局部孔隙度检测理论算法。本文对提出的声学方法和传统的光学方法进行了评价和比较。引入了表征内槽比表面积的参数，并对光学和声学方法进行了计算，3种不同NGCs计算参数值的相对误差分别为7.0%、7.9%和15.3%。声波和光学方法检测到的孔隙位置和形状一致，在导管壁中部观察到更大的孔隙度。本文给出了声学和光学方法的结果，并进一步分析了与声学因素、器件特性和图像处理方法有关的误差。
Grooved nerve guide conduits (NGCs) have been effective in the clinical treatment of peripheral nerve injury. They are generally fabricated from a micro-structured spinneret using a spinning process, which easily can cause a variety of pores and morphological deviation. The topography of internal grooves as well as the porosity can greatly influence the therapeutic effect. Traditional optical or scanning electron microscopy (SEM) methods can be used to image the grooves; however, these methods are destructive and require slicing NGCs to prepare specimens suitable for imaging. Moreover, lengthy experiments and large batches of NGCs are required to ensure reliable results from both in vitro experiments and clinical studies. In this paper, a non-destructive method for evaluating the grooves and porosity of NGCs is proposed using ultrasonic imaging combined with rotary scanning and an image analysis algorithm. Two ultrasonic methods were used: a 25-MHz point-focus ultrasonic transducer applied to observe axial cross sections of the conduits and a 100-MHz point-focus ultrasonic transducer to detect large pores caused by defects. Furthermore, a theoretical algorithm for detecting the local porosity of a conduit based on density is proposed. Herein, the proposed acoustic method and traditional optical methods are evaluated and compared. A parameter representing the specific surface area of the internal grooves is introduced and computed for both the optical and acoustic methods, and the relative errors of the computed parameter values for three different NGCs were 7.0%, 7.9%, and 15.3%. The detected location and shape of pores were consistent between the acoustic and optical methods, and greater porosity was observed in the middle of the conduit wall. In this paper, the results of the acoustic and optical methods are presented and the errors relating to the acoustic factors, device characteristics, and image processing method are further analyzed.