Christian Karl Eisen, Patrick Liebig, Jürgen Herrler, Dieter Ritter, Simon Lévy, Michael Uder, Armin Michael Nagel, David Grodzki
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Measurements and simulations are conducted across various body parts and image orientations.</p><p><strong>Results: </strong>Phantom measurements demonstrate up to a 3.5-fold reduction in residual fat signal compared to Gaussian fat saturation. In vivo evaluations show improvements up to sixfold for dorsal subcutaneous fat in sagittal cervical spine acquisitions. The versatility of the tailored trajectory is confirmed through sagittal foot/ankle, coronal, and transversal cervical spine experiments. Additional measurements indicate that excitation field (B1) information can be disregarded at 1.5 T. Acceleration methods reduce computation time to a few seconds.</p><p><strong>Discussion: </strong>An individual pulse design that primarily compensates for main field (B0) inhomogeneities in fat pre-saturation is successfully implemented within an online \"push-button\" workflow. 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引用次数: 0
摘要
目的通过快速在线单通道频谱-空间(SPSP)脉冲设计,补偿特定受试者的场不均匀性并提高脂肪预饱和度:方法:利用特定受试者的场图和预定义的激发 k 空间轨迹在线计算射频形状。探索了计算加速选项,以提高临床可行性。将四种优化配置与标准高斯频谱选择性预饱和脉冲进行了比较,并使用模型和志愿者(N = 5)的数据在 1.5 T 下通过涡轮自旋回波(TSE)序列与 Dixon 采集进行了比较。对不同身体部位和图像方向进行了测量和模拟:模型测量结果表明,与高斯脂肪饱和度相比,残余脂肪信号最多可减少 3.5 倍。体内评估显示,在颈椎矢状图采集中,背侧皮下脂肪信号最多可提高 6 倍。矢状脚/脚踝、冠状和横向颈椎实验证实了定制轨迹的多功能性。其他测量结果表明,在 1.5 T 时可以忽略激励场 (B1) 信息:讨论:在一个在线 "按钮 "工作流程中,成功实现了主要补偿脂肪预饱和主场(B0)不均匀性的单脉冲设计。脂肪饱和的均匀性和抑制水平都得到了改善。
Fast online spectral-spatial pulse design for subject-specific fat saturation in cervical spine and foot imaging at 1.5 T.
Objective: To compensate subject-specific field inhomogeneities and enhance fat pre-saturation with a fast online individual spectral-spatial (SPSP) single-channel pulse design.
Methods: The RF shape is calculated online using subject-specific field maps and a predefined excitation k-space trajectory. Calculation acceleration options are explored to increase clinical viability. Four optimization configurations are compared to a standard Gaussian spectral selective pre-saturation pulse and to a Dixon acquisition using phantom and volunteer (N = 5) data at 1.5 T with a turbo spin echo (TSE) sequence. Measurements and simulations are conducted across various body parts and image orientations.
Results: Phantom measurements demonstrate up to a 3.5-fold reduction in residual fat signal compared to Gaussian fat saturation. In vivo evaluations show improvements up to sixfold for dorsal subcutaneous fat in sagittal cervical spine acquisitions. The versatility of the tailored trajectory is confirmed through sagittal foot/ankle, coronal, and transversal cervical spine experiments. Additional measurements indicate that excitation field (B1) information can be disregarded at 1.5 T. Acceleration methods reduce computation time to a few seconds.
Discussion: An individual pulse design that primarily compensates for main field (B0) inhomogeneities in fat pre-saturation is successfully implemented within an online "push-button" workflow. Both fat saturation homogeneity and the level of suppression are improved.
期刊介绍:
MAGMA is a multidisciplinary international journal devoted to the publication of articles on all aspects of magnetic resonance techniques and their applications in medicine and biology. MAGMA currently publishes research papers, reviews, letters to the editor, and commentaries, six times a year. The subject areas covered by MAGMA include:
advances in materials, hardware and software in magnetic resonance technology,
new developments and results in research and practical applications of magnetic resonance imaging and spectroscopy related to biology and medicine,
study of animal models and intact cells using magnetic resonance,
reports of clinical trials on humans and clinical validation of magnetic resonance protocols.