Barthez P Y, Léveillé R, Scrivani P V
Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Ohio State University, Columbus 43210-1089, USA.
Vet Radiol Ultrasound. 1997 Sep-Oct;38(5):387-93. doi: 10.1111/j.1740-8261.1997.tb02104.x.
Side lobes and grating lobes are both unwanted parts of the ultrasound beam emitted off axis that produce image artifacts due to error in positioning the returning echo. The purpose of this study was to reproduce artifacts associated with side lobes and grating lobes in vitro using different transducer types and recognize these artifacts in vivo. A phantom, composed of a water bath, a metallic wire, and a wooden tongue depressor, was imaged using a linear array, a curved linear a vector array, and a sector mechanical transducer. When imaging the metallic wire in a transverse plane, an echogenic artifact was constantly seen on each side of the wire, with a shape and intensity variable with the transducer type. The artifact was curvilinear and concave (linear and curved linear arrays), or curvilinear and convex (vector array and the mechanical transducer). When the tongue depressor was imaged in a longitudinal plane, the artifact was a straight line (linear array), a curved convex line (curved array), a series of convex curvilinear echo (vector array) or a small convex curvilinear echo (mechanical transducer). In vivo situations similar to the phantom experiment were investigated using clinical patients. Artifacts produced in vitro were recognized in vivo when a highly reflective object (urinary bladder wall) was imaged adjacent to an anechoic region (urine). These artifacts corresponded to the principle of secondary ultrasound lobes, and were therefore interpreted as such.
旁瓣和栅瓣都是超声束轴外发射的不需要的部分，由于返回回波定位错误而产生图像伪像。本研究的目的是使用不同类型的换能器在体外重现与旁瓣和栅瓣相关的伪像，并在体内识别这些伪像。使用线性阵列、曲线线性阵列、向量阵列和扇形机械换能器对由水浴、金属丝和木制压舌板组成的仿体进行成像。在横向平面成像金属丝时，在金属丝的每一侧始终可以看到一个回声伪像，其形状和强度随换能器类型而变化。该伪像为曲线形且凹陷（线性和曲线线性阵列），或曲线形且凸起（向量阵列和机械换能器）。在纵向平面成像压舌板时，伪像为直线（线性阵列）、曲线形凸线（曲线阵列）、一系列凸曲线回声（向量阵列）或小凸曲线回声（机械换能器）。使用临床患者研究了与仿体实验类似的体内情况。当在无回声区域（尿液）附近对高反射物体（膀胱壁）进行成像时，在体内识别出了体外产生的伪像。这些伪像符合二次超声瓣的原理，因此被如此解释。
