From the Division of Neuroradiology, Diagnostic Department (G.R.I., K.O.L.), Geneva University Hospitals and University of Geneva, Geneva, Switzerland.
Department of Neurosurgery (G.R.I., I.N., V.I., S.M., K.L.S.), Geneva University Hospitals and University of Geneva, Geneva, Switzerland.
AJNR Am J Neuroradiol. 2023 Nov;44(11):1302-1308. doi: 10.3174/ajnr.A8006. Epub 2023 Oct 19.
Arterial spin-labeling is a noninvasive MR imaging technique allowing direct and quantitative measurement of brain perfusion. Arterial spin-labeling is well-established in clinics for investigating the overall cerebral perfusion, but it is still occasionally employed during tasks. The typical contrast for functional MR imaging is blood oxygen level-dependent (BOLD) imaging, whose specificity could be biased in neurologic patients due to altered neurovascular coupling. This work aimed to validate the use of functional ASL as a noninvasive tool for presurgical functional brain mapping. This is achieved by comparing the spatial accuracy of functional ASL with transcranial magnetic stimulation as the criterion standard.
Twenty-eight healthy participants executed a motor task and received a somatosensory stimulation, while BOLD imaging and arterial spin-labeling were acquired simultaneously. Transcranial magnetic stimulation was subsequently used to define hand somatotopy.
Functional ASL was found more adjacent to transcranial magnetic stimulation than BOLD imaging, with a significant shift along the inferior-to-superior direction. With respect to BOLD imaging, functional ASL was localized significantly more laterally, anteriorly, and inferiorly during motor tasks and pneumatic stimulation.
Our results confirm the specificity of functional ASL in targeting the regional neuronal excitability. Functional ASL could be considered as a valid supplementary technique to BOLD imaging for presurgical mapping when spatial accuracy is crucial for delineating eloquent cortex.
动脉自旋标记是一种非侵入性磁共振成像技术，可直接、定量测量脑灌注。动脉自旋标记在临床上已被广泛用于研究整体脑灌注，但在任务期间仍偶尔使用。功能磁共振成像的典型对比是血氧水平依赖（BOLD）成像，但由于神经血管耦联改变，其特异性在神经患者中可能存在偏差。本研究旨在验证功能动脉自旋标记作为一种非侵入性工具用于术前功能脑图的应用。这是通过将功能 ASL 的空间准确性与经颅磁刺激作为标准进行比较来实现的。
28 名健康参与者执行运动任务并接受躯体感觉刺激，同时采集 BOLD 成像和动脉自旋标记。随后使用经颅磁刺激来定义手的躯体感觉区。
与 BOLD 成像相比，功能 ASL 更接近经颅磁刺激，且在从下到上的方向上有显著的偏移。与 BOLD 成像相比，在运动任务和气动刺激期间，功能 ASL 在定位上更偏向外侧、前方和下方。
我们的结果证实了功能 ASL 在靶向区域神经元兴奋性方面的特异性。当空间准确性对于描绘功能区皮质至关重要时，功能 ASL 可以被视为 BOLD 成像的有效补充技术，用于术前映射。
