Image-Based Background Phase Error Correction in 4D Flow MRI Revisited
Image-Based Background Phase Error Correction in 4D Flow MRI Revisited
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DOI：
10.1002/jmri.25668
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发表时间：
2017-11-01
影响因子：
4.4
通讯作者：
Kozerke, Sebastian
中科院分区：
文献类型：
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作者：
Busch, Julia;Giese, Daniel;Kozerke, Sebastian
目的：为了校正相位对比磁共振成像（MRI）中的背景相位误差，广泛使用通过静止组织参考的基于图像的校正。本研究的目的是详细评估4D Flow MRI中的背景相位误差和基于图像的校正的局限性。材料和方法：在体模研究中，在两个临床3 T MR系统的典型设置下采集了4D Flow MRI数据。分析了背景误差的空间顺序，并评估了信噪比（SNR）和基于图像校正的静止组织量的最低要求。对于体内评价，在一个3 T MR系统上采集5名健康受试者的主动脉数据，包括随后在固定体模上扫描作为参考。结果：背景误差表现出一至三阶的空间变化。对于校正，需要20的最小SNR以实现小于编码速度的0.4%的误差。静止组织的最小量强烈依赖于空间顺序，需要至少25%、60%和75%的静止组织用于一阶、二阶和三阶校正。体内评估显示，在35-41%的静止组织可用的情况下，仅一阶校正产生显著减少（P < 0.01）。结论：4D Flow MRI中的背景相位误差范围可能从第一空间阶到第三空间阶，需要使用适当的多项式进行校正。与此同时，体内可用的固定组织数量有限，将基于图像的背景相位校正限制为一阶空间。证据等级：1技术有效性：第1阶段
Purpose: To correct background phase errors in phase-contrast magnetic resonance imaging ( MRI), image-based correction by referencing through stationary tissue is widely used. The aim of the present study was a detailed assessment of background phase errors in 4D Flow MRI and limitations of image-based correction. Materials and Methods: In a phantom study, 4D Flow MRI data were acquired for typical settings on two clinical 3T MR systems. Background errors were analyzed with respect to their spatial order and minimum requirements regarding the signal-to-noise ratio ( SNR) and the amount of stationary tissue for image-based correction were assessed. For in vivo evaluation, data of the aorta were acquired on one 3T MR system in five healthy subjects including subsequent scans on the stationary phantom as reference. Results: Background errors were found to exhibit spatial variation of first-to third-order. For correction, a minimum SNR of 20 was needed to achieve an error of less than 0.4% of the encoding velocity. The minimum amount of stationary tissue was strongly dependent on the spatial order requiring at least 25%, 60%, and 75% of stationary tissue for first-, second-, and third-order correction. In vivo evaluation showed that with 35-41% of stationary tissue available only first-order correction yielded a significant reduction ( P < 0.01). Conclusion: Background phase errors can range from first to third spatial order in 4D Flow MRI requiring correction with appropriate polynomials. At the same time, the limited amount of stationary tissue available in vivo limits imagebased background phase correction to first spatial order. Level of Evidence: 1 Technical Efficacy: Stage 1