Fritz David A, Dwyer Michael G, Bagnato Francesca, Watts Kelly L, Bratina Alessio, Zorzon Marino, Durastanti Valentina, Locatelli Laura, Millefiorini Enrico, Zivadinov Robert
Buffalo Neuroimaging Analysis Center, Department of Neurology, The Jacobs Neurological Institute, University at Buffalo, State University of New York, 14203, USA.
Neurol Res. 2006 Apr;28(3):275-9. doi: 10.1179/016164106X98152.
To test the effect of serial magnetic resonance (MR) coregistration on short-term brain volume changes using different semiautomated and automated brain volume techniques in patients with relapsing-remitting (RR) multiple sclerosis (MS). Coregistration is frequently used to increase precision in serial MR imaging (MRI) analyses. However, the effect of coregistration on measurement of whole brain volume changes from serial scans in the short term has not been tested in MS patients.
Twenty-eight patients with RR MS [mean disease duration: 4.9 years, mean age: 34.4 years and mean expanded disability status scale (EDSS): 1.4] were scanned at baseline and monthly for a period of 3 months with 2D spin-echo T1-weighted sequences obtained with nongapped 3 mm axial slices. Percent brain parenchymal fraction change (PBPFC) was calculated by a semiautomated (Buffalo) and, separately, by two automated (Buffalo automated and SIENAX) techniques, whereas percent brain volume change (PBVC) was calculated by the SIENA technique. For coregistration of serial images we used a robust, fully automated linear image coregistration tool. PBPFC and PBVC were calculated before and after coregistration, comparing scans from the following time periods: (1) baseline to month 3; (2) baseline to month 1; (3) month 1 to 2 and (4) month 2 to 3.
The highest median PBPFCs measured on non-coregistered images were detected for the baseline-to-month-3 time period and ranged from -0.11% for Buffalo semiautomated to -0.45% for Buffalo automated (p = ns). On coregistered images, the highest PBPFCs were detected for the baseline-to-month-3 time period and ranged from 0.3% for Buffalo semiautomated, -0.3% for Buffalo automated, 0.02% for SIENAX and -0.02% for SIENA (PBVC). At all time points of the study, no significant differences of median volume changes were measured on coregistered and non-coregistered images when comparing the results among the segmentation algorithms.
Over a 3 month period we did not detect short-term changes in normalized brain volumes using different measurement techniques. A longer observation period is needed to assess whether coregistration can affect the measurement of long-term brain volume changes.
采用不同的半自动和自动脑容量测量技术，测试序列磁共振（MR）配准对复发缓解型（RR）多发性硬化症（MS）患者短期脑容量变化的影响。配准常用于提高序列磁共振成像（MRI）分析的精度。然而，配准对MS患者短期序列扫描中全脑容量变化测量的影响尚未得到测试。
28例RR MS患者[平均病程：4.9年，平均年龄：34.4岁，平均扩展残疾状态量表（EDSS）：1.4]在基线期及之后3个月内每月进行扫描，采用无间隙3mm轴位切片的二维自旋回波T1加权序列。脑实质分数变化百分比（PBPFC）通过半自动（布法罗）技术计算，另外还通过两种自动技术（布法罗自动技术和SIENAX）计算，而脑容量变化百分比（PBVC）通过SIENA技术计算。对于序列图像的配准，我们使用了一种强大的、全自动的线性图像配准工具。在配准前后计算PBPFC和PBVC，并比较以下时间段的扫描结果：（1）基线期至第3个月；（2）基线期至第1个月；（3）第1个月至第2个月；（4）第2个月至第3个月。
在未配准图像上，基线期至第3个月时间段测得PBPFC中位数最高，范围从布法罗半自动技术的-0.11%到布法罗自动技术的-0.45%（p=无显著性差异）。在配准图像上，基线期至第3个月时间段测得PBPFC中位数最高，范围从布法罗半自动技术的0.3%、布法罗自动技术的-0.3%、SIENAX的0.02%到SIENA（PBVC）的-0.02%。在研究的所有时间点，比较分割算法的结果时，配准图像和未配准图像上测得的体积变化中位数无显著差异。
在3个月的时间里，我们使用不同测量技术未检测到标准化脑容量的短期变化。需要更长的观察期来评估配准是否会影响长期脑容量变化的测量。
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