Wu Junjie, Dehkharghani Seena, Nahab Fadi, Qiu Deqiang
Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, GA 30322, United States.
Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, GA 30322, United States; Department of Neurology, Emory University School of Medicine, Atlanta, GA 30322, United States.
Neuroimage Clin. 2016 Nov 17;13:116-122. doi: 10.1016/j.nicl.2016.11.018. eCollection 2017.
The purpose of this study was to measure cerebrovascular reactivity (CVR) in chronic steno-occlusive disease using a novel approach that couples BOLD imaging with acetazolamide (ACZ) vasoreactivity (aczBOLD), to evaluate dynamic effects of ACZ on BOLD and to establish the relationship between aczBOLD and dynamic susceptibility contrast (DSC) perfusion MRI. Eighteen patients with unilateral chronic steno-occlusive disease of the anterior circulation underwent a 20-min aczBOLD imaging protocol, with ACZ infusion starting at 5 min of scan initiation. AczBOLD reactivity was calculated on a voxel-by-voxel basis to generate CVR maps for subsequent quantitative analyses. Reduced CVR was observed in the diseased vs. the normal hemisphere both by qualitative and quantitative assessment (gray matter (GM): 4.13% ± 1.16% vs. 4.90% ± 0.98%, = 0.002; white matter (WM): 2.83% ± 1.23% vs. 3.50% ± 0.94%, = 0.005). In all cases BOLD signal began increasing immediately following ACZ infusion, approaching a plateau at ~ 8.5 min after infusion, with the tissue volume of reduced augmentation increasing progressively with time, peaking at 2.60 min (time range above 95% of the maximum value: 0-4.43 min) for the GM and 1.80 min (time range above 95% of the maximum value: 1.40-3.53 min) for the WM. In the diseased hemisphere, aczBOLD CVR significantly correlated with baseline DSC time-to-maximum of the residue function (T) ( = 0.008 for the WM) and normalized cerebral blood flow ( = 0.003 for the GM, and = 0.001 for the WM). AczBOLD provides a novel, safe, easily implementable approach to CVR measurement in the routine clinical environments. Further studies can establish quantitative thresholds from aczBOLD towards identification of patients at heightened risk of recurrent ischemia and cognitive decline.
本研究的目的是使用一种将血氧水平依赖性功能磁共振成像(BOLD)与乙酰唑胺(ACZ)血管反应性相结合的新方法(aczBOLD)来测量慢性狭窄闭塞性疾病中的脑血管反应性(CVR),评估ACZ对BOLD的动态影响,并建立aczBOLD与动态磁敏感对比(DSC)灌注磁共振成像之间的关系。18例单侧前循环慢性狭窄闭塞性疾病患者接受了一项20分钟的aczBOLD成像方案,ACZ输注在扫描开始5分钟后开始。逐像素计算aczBOLD反应性,以生成CVR图用于后续定量分析。通过定性和定量评估均观察到病变半球与正常半球相比CVR降低(灰质(GM):4.13%±1.16%对4.90%±0.98%,P = 0.002;白质(WM):2.83%±1.23%对3.50%±0.94%,P = 0.005)。在所有病例中,BOLD信号在ACZ输注后立即开始增加,在输注后约8.5分钟接近平台期,增强减少的组织体积随时间逐渐增加,在GM中于2.60分钟达到峰值(高于最大值95%的时间范围:0 - 4.43分钟),在WM中于1.80分钟达到峰值(高于最大值95%的时间范围:1.40 - 3.53分钟)。在病变半球中,aczBOLD CVR与基线DSC残余函数的达峰时间(T)显著相关(WM中P = 0.008)以及与标准化脑血流量相关(GM中P = 0.003,WM中P = 0.001)。AczBOLD为在常规临床环境中测量CVR提供了一种新颖、安全且易于实施的方法。进一步的研究可以从aczBOLD建立定量阈值,以识别复发缺血和认知衰退风险增加的患者。