EFFECTS OF RF AMPLIFIER DISTORTION ON SELECTIVE EXCITATION AND THEIR CORRECTION BY PREWARPING
EFFECTS OF RF AMPLIFIER DISTORTION ON SELECTIVE EXCITATION AND THEIR CORRECTION BY PREWARPING
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DOI：
10.1002/mrm.1910230204
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发表时间：
1992-02-01
影响因子：
3.3
通讯作者：
MACOVSKI, A
中科院分区：
文献类型：
--
作者：
CHAN, F;PAULY, J;MACOVSKI, A
在磁共振成像系统中，使用射频功率放大器将射频脉冲增强到足够的强度以激发主体中的核自旋。该放大器的非理想特性使选择性激励脉冲失真，而这种失真反过来又降低了片形。我们发现了两种特别麻烦的非理想行为：非线性和附带相位调制。它们的作用之一是在切片轮廓的片外区域引入不必要的“裙边”。我们提出了一种有效的校正方法，即对选择性激励脉冲进行预翘曲以补偿畸变。©1992学术出版社，Inc。
In a magnetic resonance imaging system, an RF power amplifier is employed to boost an RF pulse to sufficient strength to excite the nuclear spins in a subject. The nonideal behavior of this amplifier distorts a selective‐excitation pulse, and this distortion in turn degrades the slice profile. We have found two types of nonideal behavior particularly troublesome: nonlinearity and incidental phase modulation. One of their effects is the introduction of an unwanted “skirt” in the out‐of‐slice region of a slice profile. We present an effective method of correction in which a selective‐excitation pulse is prewarped to compensate for the distortion. © 1992 Academic Press, Inc.