Factors influencing fast low angle positive contrast steady-state free precession (FLAPS) magnetic resonance imaging
Factors influencing fast low angle positive contrast steady-state free precession (FLAPS) magnetic resonance imaging
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DOI：
10.1088/0031-9155/52/11/021
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发表时间：
2007-06-07
影响因子：
3.5
通讯作者：
Li, Debiao
中科院分区：
文献类型：
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作者：
Dharmakumar, Rohan;Koktzoglou, Ioannis;Li, Debiao
磁化介质的存在会导致磁共振图像中的信号空洞。传统上，信号空洞被用于检测此类磁扰动，但对磁化率移位介质周围的非共振自旋进行选择性磁共振成像，可以将其可视化为高强度（正对比）区域。这些正对比方法可以潜在地提高磁扰动对由于缺少质子而呈现黑暗的区域（如空气）的探测显著性。近年来，快速低角度正对比稳态自由进动（FLAPS）技术作为一种正对比成像方法被提出。本文从磁摄动器的成像参数和物理性质的角度，系统地评估了基于flaps成像的对比度特性和获取策略。结果表明，扫描参数（T-R、翻转角、B-0）、扰动剂的物理性质（移位试剂的大小和浓度）以及介质弛豫常数（T-1/ T-2）的比值是影响flaps正对比的重要因素。
The presence of susceptibility-shifting media can lead to signal voids in magnetic resonance images. While signal voids have been traditionally used to detect such magnetic perturbers, selective magnetic resonance imaging of off-resonant spins surrounding susceptibility-shifted media allows for them to be visualized as hyper-intense (positive contrast) regions. These positive contrast methods can potentially improve the detection conspicuity of magnetic perturbers against regions that appear dark due to the absence of protons, such as air. Recently, a fast low angle positive contrast steady-state free precession ( FLAPS) technique has been proposed as a positive contrast imaging method. This work systematically evaluates the contrast characteristics and acquisition strategies of FLAPS-based imaging from the standpoint of imaging parameters and physical properties of the magnetic perturbers. Results show that scan parameters (T-R, flip angle, B-0), physical properties of the perturber (size and concentration of shift reagent) and the ratio of the relaxation constants (T-1/ T-2) of the medium are significant factors influencing the FLAPS-based positive contrast.