Sabati Mohammad, Sheriff Sulaiman, Gu Meng, Wei Juan, Zhu Henry, Barker Peter B, Spielman Daniel M, Alger Jeffry R, Maudsley Andrew A
Department of Radiology, University of Miami, Miami, Florida, USA.
Department of Radiology, University of Calgary, Calgary, Canada.
Magn Reson Med. 2015 Nov;74(5):1209-20. doi: 10.1002/mrm.25510. Epub 2014 Oct 29.
To assess volumetric proton MR spectroscopic imaging (MRSI) of the human brain on multivendor MRI instruments.
Echo-planar spectroscopic imaging was developed on instruments from three manufacturers, with matched specifications and acquisition protocols that accounted for differences in sampling performance, radiofrequency (RF) power, and data formats. Intersite reproducibility was evaluated for signal-normalized maps of N-acetylaspartate (NAA), creatine (Cre), and choline using phantom and human subject measurements. Comparative analyses included metrics for spectral quality, spatial coverage, and mean values in atlas-registered brain regions.
Intersite differences for phantom measurements were less than 1.7% for individual metabolites and less than 0.2% for ratio measurements. Spatial uniformity ranged from 79% to 91%. The human studies found differences of mean values in the temporal lobe, but good agreement in other white matter regions, with maximum differences relative to their mean of under 3.2%. For NAA/Cre, the maximum difference was 1.8%. In gray matter, a significant difference was observed for frontal lobe NAA. Primary causes of intersite differences were attributed to shim quality, B0 drift, and accuracy of RF excitation. Correlation coefficients for measurements at each site were over 0.60, indicating good reliability.
A volumetric intensity-normalized MRSI acquisition can be implemented in a comparable manner across multivendor MR instruments.
在多厂商的磁共振成像（MRI）设备上评估人脑的容积质子磁共振波谱成像（MRSI）。
在三家厂商的设备上开发了回波平面波谱成像，采用了匹配的规格和采集协议，以考虑采样性能、射频（RF）功率和数据格式的差异。使用体模和人体受试者测量，对N-乙酰天门冬氨酸（NAA）、肌酸（Cre）和胆碱的信号归一化图谱进行了多中心可重复性评估。比较分析包括光谱质量、空间覆盖范围和图谱配准脑区的平均值等指标。
体模测量的多中心差异，单个代谢物小于1.7%，比值测量小于0.2%。空间均匀性范围为79%至91%。人体研究发现颞叶平均值存在差异，但其他白质区域一致性良好，相对于平均值的最大差异低于3.2%。对于NAA/Cre，最大差异为1.8%。在灰质中，额叶NAA观察到显著差异。多中心差异的主要原因归因于匀场质量、B0漂移和RF激发的准确性。各站点测量的相关系数超过0.60，表明可靠性良好。
容积强度归一化的MRSI采集可以在多厂商的MR设备上以可比的方式实现。
