利用局部动脉输入函数的动态磁敏感对比MRI量化侧支供血可预测梗死增长
Quantification of Collateral Supply with Local-AIF Dynamic Susceptibility Contrast MRI Predicts Infarct Growth
AI总结：
本研究提出局部动脉输入函数DSC灌注方法，在临床前卒中模型中证明其可准确量化软脑膜侧支供血并预测梗死增长，优于传统全局AIF。
摘要：
在缺血性卒中中，尽管存在血管闭塞，软脑膜侧支仍可向处于风险中的组织提供代偿性血流，并影响治疗反应和梗死增长。本研究旨在检验以下假设：需要采用适当的局部动脉输入函数（Local Arterial Input Function, AIF）进行局部灌注，以量化闭塞远端组织中侧支供血的程度。在临床前大脑中动脉闭塞模型中开展了七项实验。对磁共振动态磁敏感对比（dynamic susceptibility contrast, DSC）成像进行后处理，生成脑血流图，分别采用传统上选择的单一动脉输入函数全局应用于全脑（即“Global-AIF”）和一种新型的、对逆行血流敏感的自动延迟与弥散校正AIF（即“Local AIF”）。软脑膜侧支募集情况通过X射线血管造影评估，梗死增长通过连续采集的弥散加权MRI扫描评估，两者均对DSC结果设盲。X射线显示的侧支化程度与使用Local AIF在缺血半暗带中测定的定量灌注强相关（R2=0.81），而与传统选择的Global-AIF相关性较弱（R2=0.05）。使用Local-AIF计算的定量灌注与梗死增长呈负相关（局部灌注越高，梗死进展越少）（R2=0.79），而Global-AIF的相关性为R2=0.02。与传统选择的AIF相比，使用Local-AIF的局部DSC灌注能更准确地评估组织状态和软脑膜侧支化程度。这些发现支持在闭塞性疾病中使用Local-AIF来确定具有侧支供血的定量组织灌注。
英文摘要：
In ischemic stroke, leptomeningeal collaterals can provide compensatory blood flow to tissue at risk despite an occlusion, and impact treatment response and infarct growth. The purpose of this work is to test the hypothesis that local perfusion with an appropriate Local Arterial Input Function (AIF) is needed to quantify the degree of collateral blood supply in tissue distal to an occlusion. Seven experiments were conducted in a pre-clinical middle cerebral artery occlusion model. Magnetic resonance dynamic susceptibility contrast (DSC) was imaged and post-processed as cerebral blood flow maps with both a traditionally chosen single arterial input function (AIF) applied globally to the whole brain (i.e. "Global-AIF") and a novel automatic delay and dispersion corrected AIF (i.e. "Local AIF") that is sensitive to retrograde flow. Pial collateral recruitment was assessed from x-ray angiograms and infarct growth via serially acquired diffusion weighted MRI scans both blinded to DSC. The degree of collateralization at x-ray correlated strongly with quantitative perfusion determined using the Local AIF in the ischemic penumbra (R2=0.81) compared to a traditionally chosen Global-AIF (R2=0.05). Quantitative perfusion calculated using a Local-AIF was negatively correlated (less infarct progression as local perfusion increased) with infarct growth (R2 = 0.79) compared to Global-AIF (R2=0.02). Local DSC perfusion with a Local-AIF is more accurate for assessing tissue status and degree of leptomeningeal collateralization than traditionally chosen AIFs. These findings support use of a Local-AIF in determining quantitative tissue perfusion with collateral supply in occlusive disease.
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