From the Department of Radiology and Nuclear Medicine (K.P.A.B., A.J.N.), Amsterdam University Medical Center, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands
Institute of Radiopharmaceutical Cancer Research (J.P.), Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany.
AJNR Am J Neuroradiol. 2021 Jan;42(1):109-115. doi: 10.3174/ajnr.A6856. Epub 2020 Nov 12.
Although the added diagnostic value of arterial spin-labeling is shown in various cerebral pathologies, its use in clinical practice is limited. To encourage clinical adoption of ASL, we investigated the reproducibility of CBF measurements and the effects of variations in acquisition parameters compared to the recommended ASL implementation.
Thirty-four volunteers (mean age, 57.8 ± 17.0 years; range, 22-80 years) underwent two separate sessions (1.5T and 3T scanners from a single vendor) using a 15-channel head coil. Both sessions contained repeated 3D and 2D pseudocontinuous arterial spin-labeling scans using vendor-recommended acquisition parameters (recommendation paper-based), followed by three 3D pseudocontinuous arterial spin-labeling scans, two with postlabeling delays of 1600 and 2000 ms and one with increased spatial resolution. All scans were single postlabeling delay. Intrasession (identical acquisitions, scanned five minutes apart) and intersession (first 2D and 3D acquisitions of two sessions) reproducibility was examined as well as the effect of parameter variations on CBF.
Intrasession CBF reproducibility was similar across image readouts and field strengths (within-subject coefficient of variation between 4.0% and 6.7%). Intersession within-subject coefficient of variation ranged from 6.6% to 14.8%. At 3T, the 3D acquisition with a higher spatial resolution resulted in less mixing of GM and WM signal, thus decreasing the bias in GM CBF between the 2D and 3D acquisitions (ΔCBF = 2.49 mL/100g/min [< .001]). Postlabeling delay variations caused a modest bias (ΔCBF between -3.78 [< .001] and 2.83 [< .001] mL/100g/min).
Arterial spin-labeling imaging is reproducible at both field strengths, and the reproducibility is not significantly correlated with age. Furthermore, 3T tolerates more acquisition parameter variations and allows more extensive optimizations so that 3D and 2D acquisitions can be compared.
虽然动脉自旋标记在各种脑病变中的附加诊断价值已得到证实，但在临床实践中的应用仍受到限制。为了鼓励临床采用动脉自旋标记，我们研究了脑血流（CBF）测量的可重复性，并比较了不同采集参数对推荐的动脉自旋标记实施的影响。
34 名志愿者（平均年龄 57.8±17.0 岁；范围 22-80 岁）分别在 1.5T 和 3T 扫描仪（来自同一供应商）上使用 15 通道头部线圈进行两次独立的扫描。两次扫描均包含重复的 3D 和 2D 伪连续动脉自旋标记扫描，使用供应商推荐的采集参数（基于推荐论文），随后进行三次 3D 伪连续动脉自旋标记扫描，其中两次的标记后延迟为 1600ms 和 2000ms，一次的空间分辨率增加。所有扫描均为单标记后延迟。研究了两次扫描之间（相同的采集，间隔 5 分钟）和两次扫描内（第一次 2D 和 3D 采集）的可重复性，以及参数变化对 CBF 的影响。
两次扫描内的 CBF 可重复性在不同的图像读出和场强下相似（同一受试者的组内变异系数在 4.0%至 6.7%之间）。两次扫描间同一受试者的组内变异系数范围为 6.6%至 14.8%。在 3T 中，更高空间分辨率的 3D 采集导致 GM 和 WM 信号混合减少，从而降低了 2D 和 3D 采集之间 GM CBF 的偏差（ΔCBF=2.49mL/100g/min [<0.001]）。标记后延迟变化引起适度的偏差（ΔCBF 在-3.78[<.001]和 2.83[<.001]mL/100g/min 之间）。
动脉自旋标记成像在两种场强下均具有可重复性，且其可重复性与年龄无显著相关性。此外，3T 可以容忍更多的采集参数变化，并允许更广泛的优化，以便可以比较 3D 和 2D 采集。
