Scan-Rescan Repeatability and Impact of B0 and B1 Field Nonuniformity Corrections in Single-Point Whole-Brain Macromolecular Proton Fraction Mapping.
Scan-Rescan Repeatability and Impact of B0 and B1 Field Nonuniformity Corrections in Single-Point Whole-Brain Macromolecular Proton Fraction Mapping.
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单点全脑大分子质子分数映射中 B0 和 B1 场不均匀性校正的扫描重复性和影响。
DOI：
10.1002/jmri.26998
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发表时间：
2020
期刊：
影响因子：
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通讯作者：
Khodanovich,MarinaY
中科院分区：
文献类型：
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作者：
Yarnykh,VasilyL;Kisel,AlenaA;Khodanovich,MarinaY
研究背景单点大分子质子分数（MPF）成像是一种快速评价脑髓鞘形成的新的定量MRI方法。有关MPF标测对磁场不均匀性的再现性和灵敏度的信息对于临床应用是重要的。目的评估单点合成参考MPF标测中的扫描再扫描可重复性和B 0和B1场不均匀性校正值。研究类型前瞻性。人群8名健康成年志愿者进行了两次扫描，间隔11.5 ± 2.3个月。场强/序列3 T;全脑3D MPF标测方案包括三个扰相梯度回波序列，提供T1、质子密度和磁化传递对比度，分辨率为1.25 × 1.25 × 1.25 mm 3，以及B 0和B1标测序列。评估MPF标测图采用B 0和B1场非均匀性校正，仅B 0和B1校正，而且没有任何修正。在自动分割的白色物质（WM）和灰质（GM）中测量平均MPF值。统计学检验受试者内变异系数（CV）、组内相关系数（ICC）、Bland-Altman图和配对t检验，以评估扫描-再扫描可重复性。重复测量方差分析（ANOVA）比较字段corrections. ResultsMaximalRelative局部MPF错误没有校正的领域最大的非均匀性分别为B 0和B1的5%和27%，分别。B 0校正对全脑WM（P> 0.25）和GM（P> 0.98）MPF的影响不显著。由于缺乏B1校正，两种组织的正相对偏倚为4-5%（P< 0.001）。所有场校正选项的扫描-再扫描一致性相似，WM的ICC为0.80-0.81，GM为0.89-0.92。WM的CV为1.6-1.7%，GM的CV为0.7-1.0%。Data ConclusionThe single‐point method enables high reproducibility of MPF maps obtained with the same equipment.可以忽略B 0不均匀性的校正，以缩短检查时间。B1非均匀性校正提高了3 T下MPF测量的准确性。WM和GM中全脑MPF测量的可靠性不受B 0和B1场校正的影响。证据等级：2技术有效性：阶段1 J。Magn. Reson. Imaging 2020;51：1789-1798.
BackgroundSingle‐point macromolecular proton fraction (MPF) mapping is a recent quantitative MRI method for fast assessment of brain myelination. Information about reproducibility and sensitivity of MPF mapping to magnetic field nonuniformity is important for clinical applications.PurposeTo assess scan–rescan repeatability and a value of B0and B1field inhomogeneity corrections in single‐point synthetic‐reference MPF mapping.Study TypeProspective.PopulationEight healthy adult volunteers underwent two scans with 11.5 ± 2.3 months interval.Field Strength/Sequence3T; whole‐brain 3D MPF mapping protocol included three spoiled gradient‐echo sequences providing T1, proton density, and magnetization transfer contrasts with 1.25 × 1.25 × 1.25 mm3resolution and B0and B1mapping sequences.AssessmentMPF maps were reconstructed with B0and B1field nonuniformity correction, B0‐ and B1‐only corrections, and without corrections. Mean MPF values were measured in automatically segmented white matter (WM) and gray matter (GM).Statistical TestsWithin‐subject coefficient of variation (CV), intraclass correlation coefficient (ICC), Bland–Altman plots, and pairedt‐tests to assess scan–rescan repeatability. Repeated‐measures analysis of variance (ANOVA) to compare field corrections.ResultsMaximal relative local MPF errors without correction in the areas of largest field nonuniformities were about 5% and 27% for B0and B1, respectively. The effect of B0correction was insignificant for whole‐brain WM (P> 0.25) and GM (P> 0.98) MPF. The absence of B1correction caused a positive relative bias of 4–5% (P< 0.001) in both tissues. Scan–rescan agreement was similar for all field correction options with ICCs 0.80–0.81 for WM and 0.89–0.92 for GM. CVs were 1.6–1.7% for WM and 0.7–1.0% for GM.Data ConclusionThe single‐point method enables high repeatability of MPF maps obtained with the same equipment. Correction of B0inhomogeneity may be disregarded to shorten the examination time. B1nonuniformity correction improves accuracy of MPF measurements at 3T. Reliability of whole‐brain MPF measurements in WM and GM is not affected by B0and B1field corrections.Level of Evidence:2Technical Efficacy:Stage 1J. Magn. Reson. Imaging 2020;51:1789–1798.