Noninvasive Assessment of Oxygen Extraction Fraction in Chronic Ischemia Using Quantitative Susceptibility Mapping at 7 Tesla
Noninvasive Assessment of Oxygen Extraction Fraction in Chronic Ischemia Using Quantitative Susceptibility Mapping at 7 Tesla
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DOI：
10.1161/strokeaha.117.017166
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发表时间：
2017-08-01
期刊：
影响因子：
8.3
通讯作者：
Sasaki, Makoto
中科院分区：
文献类型：
--
作者：
Uwano, Ikuko;Kudo, Kohsuke;Sasaki, Makoto
背景和目的：氧摄取分数（OEF）是评估慢性缺血时代谢储备的有效指标。然而，OEF被认为只有在使用正电子发射断层扫描（PET）时才能准确测量。因此，我们调查是否OEF地图产生的磁共振定量磁化率映射（QSM）在7特斯拉使检测OEF变化时，与PET. Methods相比，41例慢性狭窄/闭塞的单侧颈内动脉或大脑中动脉进行了检查，使用7特斯拉MRI和PET扫描仪。QSM图像从3维T2* 加权图像获得，使用多重偶极子反演算法。基于QSM图像上静脉结构和脑组织之间的敏感性差异生成OEF图。结果大脑中动脉区的OEF比值在QSM-OEF和PET-OEF图之间显示出显著的相关性（r=0.69;受试者操作特征分析确定的P1.09显示PET-OEF比值显著增加的敏感性和特异性分别为0.82和0.86。PET-OEF. Conclusions在单侧颈内动脉狭窄闭塞/大脑中动脉病变患者中，7 T QSM-OEF图像上的OEF比值与PET-OEF图像上的OEF比值具有良好的相关性，表明MRI无创OEF测量可以替代PET。
Background and Purpose-The oxygen extraction fraction (OEF) is an effective metric to evaluate metabolic reserve in chronic ischemia. However, OEF is considered to be accurately measured only when using positron emission tomography (PET). Thus, we investigated whether OEF maps generated by magnetic resonance quantitative susceptibility mapping (QSM) at 7 Tesla enabled detection of OEF changes when compared with those obtained with PET.Methods-Forty-one patients with chronic stenosis/occlusion of the unilateral internal carotid artery or middle cerebral artery were examined using 7 Tesla-MRI and PET scanners. QSM images were obtained from 3-dimensional T2*-weighted images, using a multiple dipole-inversion algorithm. OEF maps were generated based on susceptibility differences between venous structures and brain tissues on QSM images. OEF ratios of the ipsilateral middle cerebral artery territory against the contralateral side were calculated on the QSM-OEF and PET-OEF images, using an anatomic template.Results-The OEF ratio in the middle cerebral artery territory showed significant correlations between QSM-OEF and PET-OEF maps (r=0.69; P1.09, as determined by receiver operating characteristic analysis, showed a sensitivity and specificity of 0.82 and 0.86, respectively, for the substantial increase in the PET-OEF ratio. Absolute QSM-OEF values were significantly correlated with PET-OEF values in the patients with increased PET-OEF.Conclusions-OEF ratios on QSM-OEF images at 7 Tesla showed a good correlation with those on PET-OEF images in patients with unilateral steno-occlusive internal carotid artery/middle cerebral artery lesions, suggesting that noninvasive OEF measurement by MRI can be a substitute for PET.