Elkady Ahmed M, Cobzas Dana, Sun Hongfu, Blevins Gregg, Wilman Alan H
Department of Biomedical Engineering, University of Alberta, Edmonton, AB, Canada.
Department of Computing Science, University of Alberta, Edmonton, AB, Canada.
J Magn Reson Imaging. 2018 Mar 14. doi: 10.1002/jmri.26004.
Combined R2* and quantitative susceptibility (QS) has been previously used in cross-sectional multiple sclerosis (MS) studies to distinguish deep gray matter (DGM) iron accumulation and demyelination.
We propose and apply discriminative analysis of regional evolution (DARE) to define specific changes in MS and healthy DGM.
Longitudinal (baseline and 2-year follow-up) retrospective study.
Twenty-seven relapsing-remitting MS (RRMS), 17 progressive MS (PMS), and corresponding age-matched healthy subjects.
FIELD STRENGTH/SEQUENCE: 4.7T 10-echo gradient-echo acquisition.
Automatically segmented caudate nucleus (CN), thalamus (TH), putamen (PU), globus pallidus, red nucleus (RN), substantia nigra, and dentate nucleus were retrospectively analyzed to quantify regional volumes, bulk mean R2*, and bulk mean QS. DARE utilized combined R2* and QS localized changes to compute spatial extent, mean intensity, and total changes of DGM iron and myelin/calcium over 2 years.
We used mixed factorial analysis for bulk analysis, nonparametric tests for DARE (α = 0.05), and multiple regression analysis using backward elimination of DGM structures (α = 0.05, P = 0.1) to regress bulk and DARE measures with the follow-up Multiple Sclerosis Severity Score (MSSS). False detection rate correction was applied to all tests.
Bulk analysis only detected significant (Q ≤ 0.05) interaction effects in RRMS CN QS (η = 0.45; Q = 0.004) and PU volume (η = 0.38; Q = 0.034). DARE demonstrated significant group differences in all RRMS structures, and in all PMS structures except the RN. The largest RRMS effect size was CN total R2* iron decrease (r = 0.74; Q = 0.00002), and TH mean QS myelin/calcium decrease for PMS (r = 0.70; Q = 0.002). DARE iron increase using total QS demonstrated the highest correlation with MSSS (r = 0.68; Q = 0.0005).
DARE enabled discriminative assessment of specific DGM changes over 2 years, where iron and myelin/calcium changes were the primary drivers in RRMS and PMS compared to age-matched controls, respectively. Specific DARE measures of MS DGM correlated with follow-up MSSS, and may reflect complex disease pathology.
3 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2018.
先前在横断面多发性硬化症（MS）研究中已使用联合R2*和定量磁化率（QS）来区分深部灰质（DGM）铁蓄积和脱髓鞘。
我们提出并应用区域演变判别分析（DARE）来定义MS和健康DGM中的特定变化。
纵向（基线和2年随访）回顾性研究。
27例复发缓解型MS（RRMS）、17例进展型MS（PMS）以及相应年龄匹配的健康受试者。
场强/序列：4.7T 10回波梯度回波采集。
对自动分割的尾状核（CN）、丘脑（TH）、壳核（PU）、苍白球、红核（RN）、黑质和齿状核进行回顾性分析，以量化区域体积、总体平均R2和总体平均QS。DARE利用联合R2和QS局部变化来计算2年内DGM铁和髓磷脂/钙的空间范围、平均强度和总体变化。
我们使用混合因子分析进行总体分析，对DARE进行非参数检验（α = 0.05），并使用DGM结构的向后排除法进行多元回归分析（α = 0.05，P = 0.1），以将总体和DARE测量值与随访的多发性硬化症严重程度评分（MSSS）进行回归分析。所有检验均应用错误发现率校正。
总体分析仅在RRMS的CN QS（η = 0.45；Q = 0.004）和PU体积（η = 0.38；Q = 0.034）中检测到显著（Q ≤ 0.05）交互作用效应。DARE显示所有RRMS结构以及除RN外的所有PMS结构均存在显著组间差异。RRMS中最大的效应量是CN总R2*铁减少（r = 0.74；Q = 0.00002），PMS中TH平均QS髓磷脂/钙减少（r = 0.70；Q = 0.002）。使用总QS的DARE铁增加与MSSS的相关性最高（r = 0.68；Q = 0.0005）。
DARE能够对2年内特定的DGM变化进行判别评估，与年龄匹配的对照组相比，铁和髓磷脂/钙变化分别是RRMS和PMS的主要驱动因素。MS DGM的特定DARE测量值与随访的MSSS相关，可能反映复杂的疾病病理。
3 技术效能：1期 《磁共振成像杂志》2018年
