Fan Xiaoyuan, Li Zhonghui, Han Guangsong, Sun Gan, Han Hualu, Hong Yuehui, Chen Shuo, You Hui, Ni Jun, Li Guobin, Li Mingli, Feng Feng
Department of Radiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
Department of Neurology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
Quant Imaging Med Surg. 2025 May 1;15(5):3824-3838. doi: 10.21037/qims-24-2274. Epub 2025 Apr 28.
Pseudo-continuous arterial spin labeling (PCASL) at 7T benefits from increased signal-to-noise ratio (SNR) and prolonged T1, but suffers from field inhomogeneities and increased specific absorption rate (SAR). We proposed that 5T magnetic resonance imaging (MRI) system may be a balanced choice for PCASL imaging. The aim of this study was to achieve whole-cerebrum PCASL imaging at ultra-high field 5T MRI system, assess the reproducibility and preliminarily explore its clinical application in moyamoya disease/syndrome.
Twenty healthy volunteers were prospectively recruited for the reproducibility analysis. Both single-delay and multi-delay PCASL sequences were scanned twice on the 5T MRI scanner separated by a 10-minute period. Uncorrected cerebral blood flow (uCBF) from single-delay arterial spin labeling (ASL), corrected cerebral blood flow (cCBF) and arterial transit time (ATT) from multi-delay ASL were computed. The reproducibility of uCBF, cCBF and ATT were evaluated by calculating intraclass correlation coefficient (ICC), within-subject coefficient of variation (wsCV) and Pearson correlation coefficients between twice scans in grey matter regions and white matter (WM). Also, 26 patients diagnosed with moyamoya disease/syndrome were included and underwent multi-delay PCASL. The severity of intracranial arteries was graded as magnetic resonance angiography (MRA) score using time-of-flight (TOF) MRA. The relationship between MRA score and cCBF/ATT were assessed by one-way analysis of variance and Pearson correlation analysis.
uCBF, cCBF and ATT showed excellent reliability in all regions with ICCs ranging from 0.856 to 0.962, wsCVs ranging from 2.39% to 6.76% and Pearson correlation coefficients ranging from 0.865 to 0.966. Multi-delay ASL demonstrated superior reproducibility of CBF quantification compared to single-delay ASL in regions with heterogeneous transit time, including WM, occipital lobe, limbic system and subcortical region. In patients with moyamoya disease/syndrome, those with higher anterior cerebral artery (ACA) or middle cerebral artery (MCA) scores exhibited lower cCBF (P<0.05). Correlation analysis showed that MRA score was negatively associated with cCBF (r=-0.540, P<0.001) and positively associated with ATT (r=0.515, P<0.001).
Whole-cerebrum PCASL imaging at 5T ultra-high field was achieved with good reproducibility and applied well in patients with moyamoya disease/syndrome, which offers a promising tool in the assessment of hemodynamic conditions in cerebrovascular diseases.
7T场强下的伪连续动脉自旋标记（PCASL）技术受益于信噪比（SNR）的提高和T1时间的延长，但受磁场不均匀性和比吸收率（SAR）增加的影响。我们提出5T磁共振成像（MRI）系统可能是PCASL成像的一个平衡选择。本研究的目的是在超高场强5T MRI系统上实现全脑PCASL成像，评估其可重复性，并初步探索其在烟雾病/烟雾综合征中的临床应用。
前瞻性招募20名健康志愿者进行可重复性分析。单延迟和多延迟PCASL序列在5T MRI扫描仪上扫描两次，间隔10分钟。计算单延迟动脉自旋标记（ASL）的未校正脑血流量（uCBF）、多延迟ASL的校正脑血流量（cCBF）和动脉通过时间（ATT）。通过计算类内相关系数（ICC）、受试者内变异系数（wsCV）以及灰质区域和白质（WM）两次扫描之间的Pearson相关系数，评估uCBF、cCBF和ATT的可重复性。此外纳入26例诊断为烟雾病/烟雾综合征的患者，进行多延迟PCASL检查。使用时间飞跃（TOF）磁共振血管造影（MRA）将颅内动脉严重程度分级为MRA评分。通过单因素方差分析和Pearson相关分析评估MRA评分与cCBF/ATT之间的关系。
uCBF、cCBF和ATT在所有区域均表现出出色的可靠性，ICC范围为0.856至0.962，wsCV范围为2.39%至6.76%，Pearson相关系数范围为0.865至0.966。在通过时间不均匀的区域，包括WM、枕叶、边缘系统和皮质下区域，多延迟ASL在CBF定量方面表现出比单延迟ASL更高的可重复性。在烟雾病/烟雾综合征患者中，大脑前动脉（ACA）或大脑中动脉（MCA）评分较高的患者cCBF较低（P<0.05）。相关分析表明，MRA评分与cCBF呈负相关（r=-0.540，P<0.001），与ATT呈正相关（r=0.515，P<0.001）。
在5T超高场强下实现了全脑PCASL成像，具有良好的可重复性，并在烟雾病/烟雾综合征患者中得到了良好应用，为评估脑血管疾病的血流动力学状况提供了一种有前景的工具。
