单选题信噪比（signal to noise ratio,SNR）是MRI最基本的质量参数，其正确的概念表述应为（）A图像的亮度与暗度之比B两个像素的信号强度之比C两个体素的信号强度之比D图像的信号强度与背景强度之比E图像的信号与噪声之比
单选题
信噪比（signal to noise ratio,SNR）是MRI最基本的质量参数，其正确的概念表述应为（）
A
图像的亮度与暗度之比
B
两个像素的信号强度之比
C
两个体素的信号强度之比
D
图像的信号强度与背景强度之比
E
图像的信号与噪声之比
参考解析
解析：
信噪比，英文名称叫做SNR或S/N（SIGNAL-NOISE RATIO)，又称为讯噪比。是指一个电子设备或者电子系统中信号与噪声的比例。这里面的信号指的是来自设备外部需要通过这台设备进行处理的电子信号，噪声是指经过该设备后产生的原信号中并不存在的无规则的额外信号（或信息），并且该种信号并不随原信号的变化而变化。
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