title: Influence of bright intramural echoes on estimates of ultrasonic attenuation from backscattered ultrasound in excised myocardium.
abstract: The purpose of this study was to quantitate the influence of bright intramural echoes on estimates of myocardial attenuation from analyses of backscattered ultrasound. To achieve this, M-mode image-based measurements of the inherent anisotropic properties of myocardial attenuation were performed on rotating myocardial specimens. The approach was to use a commercially-available ultrasonic imaging system to acquire M-mode images of 24 excised cylindrical specimens from six formalin-fixed lamb hearts for data analysis using a video signal analysis technique. As a control, through-transmission rf-based measurements were performed concurrently using a pair of focused, single-element ultrasonic transducers. We devised an objective approach to compensate M-mode results for the presence of bright intramural echoes that makes use of the rotational symmetry of the measurements. A comparison of the uncompensated and compensated estimates of attenuation shows that the effect of bright intramural echoes under the conditions of this study increases the average error in M-mode results by approximately 240% compared with that observed when such effects are minimized by compensation. For both uncompensated and compensated M-mode results, increased temporal averaging shows only a modest reduction in average error. These data suggest that for measurements of attenuation from backscattered ultrasound using M-mode images, the effects of bright intramural echoes can be a significant source of error despite increased temporal averaging and therefore may require compensation.
authors.affiliation: Department of Physics, Washington University, St. Louis, MO 63130, USA.
authors.forename: Steven L
authors.initials: SL
authors.lastname: Baldwin
authors.forename: Min
authors.initials: M
authors.lastname: Yang
authors.forename: Karen R
authors.initials: KR
authors.lastname: Marutyan
authors.forename: Kirk D
authors.initials: KD
authors.lastname: Wallace
authors.forename: Mark R
authors.initials: MR
authors.lastname: Holland
authors.forename: James G
authors.initials: JG
authors.lastname: Miller
mesh_terms: D000818:Animals; D016880:Anisotropy; D004452:Echocardiography / Q000379:methods*; D007091:Image Processing, Computer-Assisted; D066298:In Vitro Techniques; D009206:Myocardium; D019047:Phantoms, Imaging; D012756:Sheep; D012815:Signal Processing, Computer-Assisted