Optimization of reconstruction time of ultrasound computed tomography with a piecewise homogeneous region-based refract-ray model

• Published in: Ultrasonics Vol. 127; p. 106837
• Main Authors: Yuan, Yu, Zhao, Yue, Xiao, Yang, Jin, Jing, Feng, Naizhang, Shen, Yi
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.01.2023
• Subjects: Image reconstruction; Ray-based algorithm; Ultrasound computed tomography; Ultrasound refraction; Ray-based algorithm; Ultrasound refraction; Image reconstruction; Ultrasound computed tomography
• ISSN: 0041-624X; 1874-9968; 1874-9968
• DOI: 10.1016/j.ultras.2022.106837

•Ultrasound waves undergo refraction when propagate through the field of imaging.•The field of imaging is assumed to be piecewise homogeneous.•The refraction only occurs at the edges which are detected from the B-mode images.•B-mode imaging and USCT imaging correct each other in iterations.•Reconstruction time is reduced by more than 90% without loss of imaging quality. In this article, a novel ultrasound computed tomography (USCT) reconstruction algorithm for breast imaging is proposed. This algorithm is based on an ultrasound propagation model, the refract-ray model (RRM). In this model, the field of imaging is assumed as piecewise homogenous and is divided into several regions. The ultrasound propagation paths are considered polylines that only refract at the borders of the regions. The edge information is provided by B-mode imaging. Both simulations and experiments are implemented to validate the proposed algorithm. Compared with the traditional bent-ray model (BRM), the time of reconstructions using RRM decreases by over 90 %. In simulations, the imaging qualities for RRM and BRM are comparable, in terms of the root mean square error, the Tenengrad value, and the deformation of digital phantom. In the experiments, a cylindrical agar phantom is imaged using a customized imaging system. When imaging using RRM, the estimate of the phantom radius is about 0.1 mm in error, while it is about 0.3 mm in error using BRM. Moreover, the Tenengrad value of the result using RRM is much higher than that using BRM (9.76 compared to 0.79). The results show that the proposed algorithm can better delineate the phantom within a water bath. In future work, further experimental work is required to validate the method for improving imaging quality under breast-mimicking imaging conditions.