Subtle blood-brain barrier leakage rate and spatial extent: Considerations for dynamic contrast-enhanced MRI
Subtle blood-brain barrier leakage rate and spatial extent: Considerations for dynamic contrast-enhanced MRI
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DOI：
10.1002/mp.12328
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发表时间：
2017-08-01
期刊：
影响因子：
3.8
通讯作者：
Backes, Walter H.
中科院分区：
文献类型：
--
作者：
van de Haar, Harm J.;Jansen, Jacobus F. A.;Backes, Walter H.
目的：动态对比增强 (DCE) MRI 可用于测量血脑屏障 (BBB) 渗漏。在小血管疾病和痴呆等神经退行性疾病中，泄漏可能非常微妙，并且相应的信号可能相当嘈杂。由于这些原因，需要优化的 DCE-MRI 测量和研究设计。为此，引入了一种指示渗漏空间范围的新测量方法，并探讨了扫描时间和样本大小的影响。方法：对 16 名早期阿尔茨海默病 (AD) 患者和 17 名健康对照者进行双时间分辨率 DCE-MRI。使用渗漏图的噪声校正直方图分析，计算皮质灰质和白质中的渗漏率 (K-i) 和可检测渗漏组织的体积分数 (v(L))，以量化 BBB 渗漏的空间范围。利用真实的 K-i 直方图进行计算机模拟，模拟噪声和 K-i 值变化的强烈影响，以了解扫描时间对估计泄漏的影响。结果：平均 K-i 非常低（10(-4) min(-1) 量级），并且受噪声影响很大，导致 K-i 在较短的扫描时间内被越来越高估。在白质中，早期 AD 患者和对照组之间的 K-i 没有差异，但患者皮质中的 K-i 较高，在扫描时间 14.5 分钟后达到显着性。为了检测组间差异，v(L) 被证明更合适，与对照组相比，扫描时间 8 分钟后，患者的皮质值显着更高，15.5 分钟后的白质值显着更高。结论：提出了几种提高 DCE-MRI 实验对细微 BBB 渗漏灵敏度的方法。我们提供了 v(L) 作为一种有吸引力且可能更省时的替代方案，用于检测与渗漏率 K-i 相比细微且广泛的血脑屏障渗漏的群体差异。关于组大小和扫描时间的建议是根据统计功效计算提出的，以帮助未来的研究。 (C) 2017年美国医学物理学家协会
Purpose: Dynamic contrast-enhanced (DCE) MRI can be used to measure blood-brain barrier (BBB) leakage. In neurodegenerative disorders such as small vessel disease and dementia, the leakage can be very subtle and the corresponding signal can be rather noisy. For these reasons, an optimized DCE-MRI measurement and study design is required. To this end, a new measure indicative of the spatial extent of leakage is introduced and the effects of scan time and sample size are explored.Methods: Dual-time resolution DCE-MRI was performed in 16 patients with early Alzheimer's disease (AD) and 17 healthy controls. The leakage rate (K-i) and volume fraction of detectable leaking tissue (v(L)) to quantify the spatial extent of BBB leakage were calculated in cortical gray matter and white matter using noise-corrected histogram analysis of leakage maps. Computer simulations utilizing realistic K-i histograms, mimicking the strong effect of noise and variation in K-i values, were performed to understand the influence of scan time on the estimated leakage.Results: The mean K-i was very low (order of 10(-4) min(-1)) and highly influenced by noise, causing the K-i to be increasingly overestimated at shorter scan times. In the white matter, the K-i was not different between patients with early AD and controls, but was higher in the cortex for patients, reaching significance after 14.5 min of scan time. To detect group differences, v(L) proved more suitable, showing significantly higher values for patients compared with controls in the cortex after 8 minutes of scan time, and in white matter after 15.5 min.Conclusions: Several ways to improve the sensitivity of a DCE-MRI experiment to subtle BBB leakage were presented. We have provided v(L) as an attractive and potentially more time-efficient alternative to detect group differences in subtle and widespread blood-brain barrier leakage compared with leakage rate K-i. Recommendations on group size and scan time are made based on statistical power calculations to aid future research. (C) 2017 American Association of Physicists in Medicine