Diffusion tensor imaging: the normal evolution of ADC, RA, FA, and eigenvalues studied in multiple anatomical regions of the brain
Diffusion tensor imaging: the normal evolution of ADC, RA, FA, and eigenvalues studied in multiple anatomical regions of the brain
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DOI：
10.1007/s00234-008-0488-1
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发表时间：
2009-04-01
期刊：
影响因子：
2.8
通讯作者：
Mentzel, Hans-Joachim
中科院分区：
文献类型：
--
作者：
Loebel, Ulrike;Sedlacik, Jan;Mentzel, Hans-Joachim
我们的工作的目的是调查的过程中，健康患者的髓鞘使用扩散参数表观扩散系数（ADC），相对各向异性（RA），分数各向异性（FA），和特征值。使用拟合函数的斜率m来评估磁共振依赖性变化，拟合函数最好地描述了data.72例（3周-19岁）没有病理性磁共振成像结果，从我们机构5年内使用弥散张量成像扫描的所有儿科患者中选择。计算ADC、RA、FA和特征值图，并在前/后脑桥、胼胝体（CC）前/压部、内囊（IC）前/后肢和白色（WM）区域（额、颞、顶、枕WM）中选择感兴趣区域。采用斯皮尔曼相关系数和回归分析进行统计学分析，ADC的平均值范围为71.6 x 10（-5）至90.3 x 10（-5）mm（2）/s（脑桥/顶叶WM），RA为0.32-0.94（额叶WM/CC），FA为0.36-0.81（额叶WM/压部）。对数拟合函数最好地描述了数据。强烈的年龄影响，观察CC，脑桥，顶叶/额叶WM和变化是显着的所有三个特征值，最明显的垂直特征值。RA和FA的变化取决于结构各向异性，ADC、RA、FA和特征值随年龄的变化与以前的研究结果一致。检测到的RA和FA的变化因两个参数的不同比例而异。我们发现，与FA相比，使用大部分线性缩放的RA为评估年龄依赖性结构变化提供了更有价值的信息。此外，我们报告的扩散参数研究的规范值。
The aim of our work was to investigate the process of myelination in healthy patients using the diffusion parameters apparent diffusion coefficient (ADC), relative anisotropy (RA), fractional anisotropy (FA), and eigenvalues. Age-dependent changes were assessed using the slope m of the fit functions that best described the data.Seventy-two patients (3 weeks-19 years) without pathological magnetic resonance imaging findings were selected from all pediatric patients scanned with diffusion tensor imaging over a 5-year period at our institution. ADC, RA, FA, and eigenvalue maps were calculated and regions of interest were selected in anterior/posterior pons, genu/splenium of corpus callosum (CC), anterior/posterior limb of internal capsule (IC), and white matter (WM) regions (frontal, temporal, parietal, occipital WM). Statistical analysis was performed using Spearman correlation coefficient and regression analysis.Mean values ranged 71.6 x 10(-5) to 90.3 x 10(-5) mm(2)/s (pons/parietal WM) for ADC, 0.32-0.94 (frontal WM/CC) for RA, and 0.36-0.81 (frontal WM/splenium) for FA. Logarithmic fit functions best described the data. Strong age influences were observed for CC, pons, and parietal/frontal WM and changes were significant for all three eigenvalues, most pronounced for perpendicular eigenvalues. Changes in RA and FA differed depending on the structure anisotropy.Changes observed for ADC, RA, FA, and eigenvalues with age were consistent with previous findings. Changes detected for RA and FA varied due to the different scaling of both parameters. We found that the use of the largely linear scaled RA adds more valuable information for the assessment of age-dependent structural changes as compared to FA. Additionally, we report normative values for the diffusion parameters studied.