Department of Neuroradiology, Hôpital Pontchaillou, University Hospital Rennes, Rennes, France.
Neuroimage. 2011 Sep 1;58(1):157-67. doi: 10.1016/j.neuroimage.2011.06.011. Epub 2011 Jun 14.
Functional arterial spin labeling (fASL) is an innovative biomarker of neuronal activation that allows direct and absolute quantification of activation-related CBF and is less sensitive to venous contamination than BOLD fMRI. This study evaluated fASL for motor activation mapping in comparison with BOLD fMRI in terms of involved anatomical area localization, intra-individual reproducibility of location, quantification of neuronal activation, and spatial accuracy. Imaging was performed at 3T with a 32-channel coil and dedicated post-processing tools were used. Twelve healthy right-handed subjects underwent fASL and BOLD fMRI while performing a right hand motor activation task. Three sessions were performed 7days apart in similar physiological conditions. Our results showed an activation in the left primary hand motor area for all 36 sessions in both fASL and BOLD fMRI. The individual functional maps for fASL demonstrated activation in ipsilateral secondary motor areas more often than the BOLD fMRI maps. This finding was corroborated by the group maps. In terms of activation location, fASL reproducibility was comparable to BOLD fMRI, with a distance between activated volumes of 2.1mm and an overlap ratio for activated volumes of 0.76, over the 3 sessions. In terms of activation quantification, fASL reproducibility was higher, although not significantly, with a CVintra of 11.6% and an ICC value of 0.75. Functional ASL detected smaller activation volumes than BOLD fMRI but the areas had a high degree of co-localization. In terms of spatial accuracy in detecting activation in the hand motor area, fASL had a higher specificity (43.5%) and a higher positive predictive value (69.8%) than BOLD fMRI while maintaining high sensitivity (90.7%). The high intra-individual reproducibility and spatial accuracy of fASL revealed in the present study will subsequently be applied to pathological subjects.
功能动脉自旋标记（fASL）是一种创新的神经激活生物标志物，可直接和绝对定量激活相关的 CBF，并且比 BOLD fMRI 对静脉污染不敏感。本研究评估了 fASL 在运动激活映射方面与 BOLD fMRI 的比较，包括涉及的解剖区域定位、个体内位置的可重复性、神经元激活的定量以及空间准确性。成像在 3T 上进行，使用 32 通道线圈和专用的后处理工具。12 名健康的右利手受试者在手运动激活任务中进行了 fASL 和 BOLD fMRI 扫描。在相似的生理条件下，3 次扫描间隔 7 天进行。我们的结果显示，在所有 36 次 fASL 和 BOLD fMRI 扫描中，所有受试者的左侧初级手运动区都有激活。fASL 的个体功能图显示同侧次级运动区的激活比 BOLD fMRI 图更频繁。这一发现得到了组图的证实。就激活位置而言，fASL 的可重复性与 BOLD fMRI 相当，在 3 次扫描中，激活体积之间的距离为 2.1mm，激活体积的重叠率为 0.76。在激活定量方面，fASL 的可重复性虽然不显著，但更高，CVintra 为 11.6%，ICC 值为 0.75。fASL 检测到的激活体积小于 BOLD fMRI，但这些区域具有高度的共定位。就检测手部运动区激活的空间准确性而言，fASL 的特异性（43.5%）和阳性预测值（69.8%）高于 BOLD fMRI，同时保持了较高的灵敏度（90.7%）。本研究中揭示的 fASL 的个体内高可重复性和空间准确性将随后应用于病理受试者。
