ULTRASOUND FOCAL LESION DETECTABILITY PHANTOMS
ULTRASOUND FOCAL LESION DETECTABILITY PHANTOMS
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DOI：
10.1118/1.596589
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发表时间：
1991-11-01
期刊：
影响因子：
3.8
通讯作者：
FRANK, GR
中科院分区：
文献类型：
--
作者：
MADSEN, EL;ZAGZEBSKI, JA;FRANK, GR
本文介绍了两种用于评估超声扫描仪在小病灶可检测性方面的性能的模型。 体模中的球形模拟损伤具有2.4、3.0和4.0 mm的直径，并且反向散射系数比周围组织模拟材料的反向散射系数低16、9和6 dB，后者模拟正常组织，例如肝脏。 随机定位和相对大量的病变处理与将正常纹理波动（实质组织的超声图像的特征）误认为小病变相关的统计问题。 所有病变的超声特性与周围物质的超声特性相同，但背向散射系数除外;因此，不存在由衰减、混响和/或折射引起的伪影，更深病变的可检测性不受更近端病变的影响。 概述了一种方法，用于使用体模来确定给定对象对比度和尺寸的局灶性病变的分辨率或可检测性的边界近端和远端深度。 涉及5名受试者的观察者依赖性测试导致远端和近端深度的标准差小于0.5 cm。 18个月后重复的观察者依赖性测试显示结果几乎没有变化。 此外，由两个有经验的观察员获得的结果也给出了各种特定的扫描仪，扫描头，和扫描参数。
Two phantoms for assessing the performance of ultrasound scanners regarding detectability of small focal lesions are described. The spherical simulated lesions in the phantoms have diameters of 2.4, 3.0, and 4.0 mm and backscatter coefficients which are 16, 9, and 6 dB below that of the surrounding tissue-mimicking material, the latter simulating normal tissue such as liver. Random positioning and relatively large numbers of lesions deal with the statistical problem related to mistaking a normal textural fluctuation, characteristic of ultrasound images of parenchymal tissue, to be a small lesion. All lesions have ultrasonic properties that are the same as those of the surrounding material except for the backscatter coefficient; therefore, artifacts resulting from attenuation, reverberation, and/or refraction are absent, and detectability of deeper lesions is not influenced by the presence of more proximal ones. A method is outlined for using the phantoms to determine bounding proximal and distal depths of resolution, or detectability, of focal lesions of a given object contrast and size. Tests for observer dependence involving five subjects resulted in standard deviations in the distal and proximal depths of less than 0.5 cm. A repeat of the observer dependence tests 18 months later showed little change in the results. In addition, results obtained by two experienced observers are also given for a variety of specific scanners, scanning heads, and scanning parameters.