同时进行的相位对比 MRI 和 PET 无创定量健康受试者和脑血管病患者的脑血流和反应性。
Simultaneous phase-contrast MRI and PET for noninvasive quantification of cerebral blood flow and reactivity in healthy subjects and patients with cerebrovascular disease.
机构信息
Department of Radiology, Stanford University, Stanford, California, USA.
Department of Neurosurgery, Tokyo Medical and Dental University, Tokyo, Japan.
出版信息
J Magn Reson Imaging. 2020 Jan;51(1):183-194. doi: 10.1002/jmri.26773. Epub 2019 May 1.
BACKGROUND
H O-positron emission tomography (PET) is considered the reference standard for absolute cerebral blood flow (CBF). However, this technique requires an arterial input function measured through continuous sampling of arterial blood, which is invasive and has limitations with tracer delay and dispersion.
PURPOSE
To demonstrate a new noninvasive method to quantify absolute CBF with a PET/MRI hybrid scanner. This blood-free approach, called PC-PET, takes the spatial CBF distribution from a static H O-PET scan, and scales it to the whole-brain average CBF value measured by simultaneous phase-contrast MRI.
STUDY TYPE
Observational.
SUBJECTS
Twelve healthy controls (HC) and 13 patients with Moyamoya disease (MM) as a model of chronic ischemic disease.
FIELD STRENGTH/SEQUENCES: 3T/2D cardiac-gated phase-contrast MRI and H O-PET.
ASSESSMENT
PC-PET CBF values from whole brain (WB), gray matter (GM), and white matter (WM) in HCs were compared with literature values since 2000. CBF and cerebrovascular reactivity (CVR), which is defined as the percent CBF change between baseline and post-acetazolamide (vasodilator) scans, were measured by PC-PET in MM patients and HCs within cortical regions corresponding to major vascular territories. Statistical Tests: Linear, mixed effects models were created to compare CBF and CVR, respectively, between patients and controls, and between different degrees of stenosis.
RESULTS
The mean CBF values in WB, GM, and WM in HC were 42 ± 7 ml/100 g/min, 50 ± 7 ml/100 g/min, and 23 ± 3 ml/100 g/min, respectively, which agree well with literature values. Compared with normal regions (57 ± 23%), patients showed significantly decreased CVR in areas with mild/moderate stenosis (47 ± 17%, P = 0.011) and in severe/occluded areas (40 ± 16%, P = 0.016). Data Conclusion: PC-PET identifies differences in cerebrovascular reactivity between healthy controls and cerebrovascular patients. PC-PET is suitable for CBF measurement when arterial blood sampling is not accessible, and warrants comparison to fully quantitative H O-PET in future studies.
LEVEL OF EVIDENCE
3 Technical Efficacy Stage: 2 J. Magn. Reson. Imaging 2019. J. Magn. Reson. Imaging 2020;51:183-194.
背景
正电子发射断层扫描（PET）被认为是绝对脑血流（CBF）的参考标准。然而，这种技术需要通过连续采集动脉血来测量动脉输入函数，这是一种侵入性的方法，并且存在示踪剂延迟和弥散的限制。
目的
展示一种使用 PET/MRI 混合扫描仪定量绝对 CBF 的新非侵入性方法。这种无血方法称为 PC-PET，它从静态 H O-PET 扫描中的空间 CBF 分布获取数据，并将其与同时进行的相位对比 MRI 测量的全脑平均 CBF 值进行缩放。
研究类型
观察性。
受试者
12 名健康对照者（HC）和 13 名作为慢性缺血性疾病模型的烟雾病（MM）患者。
磁场强度/序列：3T/2D 心脏门控相位对比 MRI 和 H O-PET。
评估
将 HC 全脑（WB）、灰质（GM）和白质（WM）的 PC-PET CBF 值与 2000 年以来的文献值进行比较。通过 PC-PET 在 MM 患者和 HC 中测量皮质区域对应主要血管区域的 CBF 和脑血管反应性（CVR），后者定义为基线和乙酰唑胺（血管扩张剂）扫描之间的 CBF 变化百分比。
统计检验
分别为患者和对照组之间以及不同狭窄程度之间的 CBF 和 CVR 创建线性、混合效应模型进行比较。
结果
HC 的 WB、GM 和 WM 的平均 CBF 值分别为 42 ± 7 ml/100 g/min、50 ± 7 ml/100 g/min 和 23 ± 3 ml/100 g/min，与文献值吻合良好。与正常区域（57 ± 23%）相比，患者在轻度/中度狭窄区域（47 ± 17%，P = 0.011）和严重/闭塞区域（40 ± 16%，P = 0.016）显示出明显降低的 CVR。
数据结论
PC-PET 可识别健康对照者和脑血管病患者之间的脑血管反应性差异。当无法进行动脉采血时，PC-PET 适合用于 CBF 测量，在未来的研究中需要与完全定量的 H O-PET 进行比较。
证据水平
3 技术功效阶段：2 J. Magn. Reson. Imaging 2019. J. Magn. Reson. Imaging 2020;51:183-194.
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