村山 宏明 ¹, 木村 文隆¹, 三宅 康二¹, 鶴岡 信治¹, 本康 宗信², 関岡 清次², 中野 聳²

Hiroaki MURAYAMA¹, Fumitaka KIMURA¹, Yasuji MIYAKE¹, Shinji TSURUOKA¹, Munenobu MOTOYASU², Kiyotsugu SEKIOKA², Takeshi NAKANO²

¹三重大学工学部情報工学科, ²三重大学電気電子工学科, ³三重大学第1内科

¹Faculty of Engineering, Mie University, ²Faculty of Engineering, Mie University, ³First Department of Internal Medicine, Mie University

キーワード : High frame-rate echocardiography, Phasic local wall motion, Serial frame subtraction

Echocardiography is one of the most popular modalities used to evaluate local cardiac wall function, because it is easy to use and it functions in real time. We developed a method to quantify phasic local wall motion from serial frame-subtraction of high frame-rate echocardiography, which has recently become commercially available. B-mode images with a resolution of 640×512 pixels and produced in 6-bit gray-scale are transferred to a workstation over one cardiac cycle. Prior to frame-subtraction, a temporal filter is applied to remove speckle noise. After subtraction, each pixel is binarized with an appropriate threshold value. Local wall motion is estimated using principal-component analysis of the subtracted image within appropriate regions of interest on the endocardial border. Estimated direction and level of motion are color coded, and each frame is ordered along a time axis to make up the three-dimensional image (comprising two spatial and one temporal dimension). Advantages of this approach include the ease with which it shows cardiac asynchrony and abnormal wall motion in a single view.