Division of Musculoskeletal Imaging, Department of Medical Imaging, Mount Sinai Hospital and the University Health Network, University of Toronto, Toronto, ON, Canada.
AJR Am J Roentgenol. 2010 Jan;194(1):W65-72. doi: 10.2214/AJR.09.2517.
The purposes of this study were to determine the intrasubject side-to-side variability of quantitative and qualitative measures of diffusion tensor imaging (DTI) and fiber tractography of the median nerves and to determine the precision of quantitative measurements and fiber tractography.
Fifteen healthy volunteers (seven men, eight women; mean age, 31.2 years) underwent DTI of both wrists with a single-shot spin-echo-based echo-planar imaging sequence (TR/TE, 7,000/103; b value 1,025 s/mm2). Postprocessing included fiber tractography and quantitative analysis of fiber length, fiber density index, fractional anisotropy, apparent diffusion coefficient, and signal-to-noise ratio. Two readers in consensus graded the quality of fiber tract images of the two wrists as equal, slightly different, or very different. Fiber tractography and all analyses were repeated after 3 weeks, and the images from the two sessions were compared.
No statistically significant side-to-side differences in quantitative data were found (p=0.054-0.999). In all subjects, the quality of fiber tract images of the right and left median nerves was either slightly or very different. Between the initial and the second quantitative analyses, no statistically significant differences (p=0.086-0.898) were found, and the quality of fiber tract images was rated equal for nine of 15 subjects (60%) and slightly different for six of 15 subjects (40%).
Preliminary results indicate that quantitative evaluation of DTI of the median nerve is precise. The absence of statistically significant intrasubject side-to-side variability in quantitative data suggests that the healthy contralateral nerve can be used as an internal control. Observed side-to-side variability in the quality of fiber tract images, however, rules out side-to-side comparisons in fiber tractography.
本研究旨在确定正中神经弥散张量成像（DTI）和纤维束追踪的定量和定性测量的个体内侧-侧变异性，并确定定量测量和纤维束追踪的精度。
15 名健康志愿者（7 名男性，8 名女性；平均年龄 31.2 岁）接受了双侧手腕的单次激发基于自旋回波的回波平面成像序列（TR/TE，7000/103；b 值 1025 s/mm2）的 DTI。后处理包括纤维束追踪和纤维长度、纤维密度指数、各向异性分数、表观扩散系数和信噪比的定量分析。两位读者以共识的方式将两只手腕的纤维束图像质量评为相等、略有不同或差异很大。3 周后重复纤维束追踪和所有分析，并比较两次扫描的图像。
定量数据没有发现统计学上的侧-侧差异（p=0.054-0.999）。在所有受试者中，右侧和左侧正中神经的纤维束图像质量要么略有不同，要么差异很大。在初次和第二次定量分析之间，没有发现统计学上的差异（p=0.086-0.898），并且 15 名受试者中有 9 名（60%）的纤维束图像质量评为相等，15 名受试者中有 6 名（40%）的纤维束图像质量评为略有不同。
初步结果表明，正中神经 DTI 的定量评估是精确的。定量数据中没有统计学上的个体内侧-侧变异性表明，健康的对侧神经可以作为内部对照。然而，纤维束图像质量的侧-侧变异性排除了纤维束追踪的侧-侧比较。
