title: Real-time texture analysis for identifying optimum microbubble concentration in 2-D ultrasonic particle image velocimetry.
abstract: Many recent studies on ultrasonic particle image velocimetry (Echo PIV) showed that the accuracy of two-dimensional (2-D) flow velocity measured depends largely on the concentration of ultrasound contrast agents (UCAs) during imaging. This article presents a texture-based method for identifying the optimum microbubble concentration for Echo PIV measurements in real-time. The texture features, standard deviation of gray level, and contrast, energy and homogeneity of gray level co-occurrence matrix were extracted from ultrasound contrast images of rotational and pulsatile flow (10 MHz) in vitro and in vivo mouse common carotid arterial flow (40 MHz) with UCAs at various concentrations. The results showed that, at concentration of 0.8∼2 × 10³ bubbles/mL in vitro and 1∼5 × 10⁵ bubbles/mL in vivo, image texture features had a peak value or trough value, and velocity vectors with high accuracy can be obtained. Otherwise, poor quality velocity vectors were obtained. When the texture features were used as a feature set, the accuracy of K-nearest neighbor classifier can reach 86.4% in vitro and 87.5% in vivo, respectively. The texture-based method is shown to be able to quickly identify the optimum microbubble concentration and improve the accuracy for Echo PIV imaging.
authors.affiliation: Paul C. Lauterbur Research Center for Biomedical Imaging, Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.
authors.forename: Lili
authors.initials: L
authors.lastname: Niu
authors.forename: Ming
authors.initials: M
authors.lastname: Qian
authors.forename: Liang
authors.initials: L
authors.lastname: Yan
authors.forename: Wentao
authors.initials: W
authors.lastname: Yu
authors.forename: Bo
authors.initials: B
authors.lastname: Jiang
authors.forename: Qiaofeng
authors.initials: Q
authors.lastname: Jin
authors.forename: Yanping
authors.initials: Y
authors.lastname: Wang
authors.forename: Robin
authors.initials: R
authors.lastname: Shandas
authors.forename: Xin
authors.initials: X
authors.lastname: Liu
authors.forename: Hairong
authors.initials: H
authors.lastname: Zheng
mesh_terms: D000818:Animals; D001783:Blood Flow Velocity; D002339:Carotid Arteries / Q000000981:diagnostic imaging*; D003287:Contrast Media / Q000737:chemistry / Q000493:pharmacokinetics*; D051379:Mice; D045423:Microbubbles; D010316:Particle Size; D019047:Phantoms, Imaging; D011673:Pulsatile Flow; D012212:Rheology / Q000379:methods*; D014463:Ultrasonography / Q000379:methods*
chemical_list: D003287:Contrast Media