MAXIMIZING SIGNAL-TO-NOISE AND CONTRAST-TO-NOISE RATIOS IN FLASH IMAGING
MAXIMIZING SIGNAL-TO-NOISE AND CONTRAST-TO-NOISE RATIOS IN FLASH IMAGING
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DOI：
10.1016/0730-725x(87)90041-5
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发表时间：
1987-01-01
影响因子：
2.5
通讯作者：
STARK, DD
中科院分区：
文献类型：
--
作者：
HENDRICK, RE;KNEELAND, JB;STARK, DD
本文提出了一种分析的信噪比和对比度噪声从小倾角，梯度反转（FLASH）成像。分析和数值技术被用来确定延迟时间和尖端角度，最大限度地提高信噪比每单位时间从一个单一的组织。使用类似的程序来确定延迟时间和尖端角度，该延迟时间和尖端角度最大化作为组织特性和脉冲序列采样时间的函数的一对组织的每单位时间的T1诱导和T-2* 诱导的对比度噪声。通过比较两个序列每单位时间的信噪比和对比度噪声比，量化了优化的FLASH成像优于优化的自旋回波成像的优势。图像用于确认这些数值结果，以比较由梯度反转与180 °产生的噪声水平。重新定相脉冲，并评估静态磁场不均匀性对FLASH成像的可能不利影响。
This paper presents an analysis of signal-to-noise ratios and contrast-to-noise from small tip angle, gradient reversal (FLASH) imaging. Analytic and numerical techniques are used to determine the delay times and tip angles that maximize signal-to-noise per unit time from a single tissue. Similar procedures are used to determine the delay times and tip angles that maximize both T1-induced and T-2*-induced contrast-to-noise per unit time for a pair of tissues as a function of tissue characteristics and pulse sequence sampling times. The advantage of optimized FLASH imaging over optimized spin-echo imaging is quantitated by comparing signal-to-noise and contrast-to-noise ratios per unit time from the two sequences. Images are used to confirm these numerical results, to compare noise levels resulting from gradient reversals versus 180.degree. rephasing pulses and to assess the possible adverse effects of static magnetic field inhomogeneities on FLASH imaging.