Blood-flow magnetic resonance imaging of the retina
Blood-flow magnetic resonance imaging of the retina
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DOI：
10.1016/j.neuroimage.2007.10.030
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发表时间：
2008-02-15
期刊：
影响因子：
5.7
通讯作者：
Duong, Timothy Q.
中科院分区：
文献类型：
--
作者：
Li, Yingxia;Cheng, Haiying;Duong, Timothy Q.
本研究描述了一种新的磁共振成像（MRI）应用，用于对基础血流、生理诱导的血流变化以及异氟烷浓度对视网膜血流的影响进行成像。采用带有独立颈部线圈进行自旋标记的连续动脉自旋标记技术，以90×90×1500微米的分辨率对大鼠视网膜的血流进行成像。在1%异氟烷条件下，整个视网膜的平均血流为6.3±1.0毫升/克/分钟，这与使用其他技术所报道的视网膜高血流情况相符。除了在视神经乳头周围略有下降以及在视网膜末端的远端边缘显著下降外，视网膜长度方向上的血流相对恒定。由于血管收缩，高氧（100% O₂）使血流相对于基线（空气）减少25±6%。由于血管舒张，高碳酸血症（5% CO₂ + 21% O₂）使血流增加16±6%。将异氟烷（一种强效血管扩张剂）浓度增加到1.5%，血流增加到9.3±2.7毫升/克/分钟。通过在MRI扫描仪中处死动物后重复测量，证实血流信号是真实的。本研究证明了一个概念，即可以使用MRI测量视网膜的定量血流，且不受深度限制。血流MRI有可能为视网膜生理学提供独特的见解，作为某些视网膜疾病的早期生物标志物，并可补充基于光学的成像技术。（C）2007爱思唯尔公司。保留所有权利。
This study describes a novel MRI application to image basal blood flow, physiologically induced blood-flow changes, and the effects of isoflurane concentration on blood flow in the retina. Continuous arterial-spin-labeling technique with a separate neck coil for spin labeling was used to image blood flow of the rat retina at 90 x 90 x 1500-mu m resolution. The average blood flow of the whole retina was 6.3 +/- 1.0 ml/g/min under 1% isoflurane, consistent with the high blood flow in the retina reported using other techniques. Blood flow is relatively constant along the length of the retina, except it dipped slightly around the optic nerve head and dropped significantly at the distal edges where the retina terminates. Hyperoxia (100% O-2) decreased blood flow 25 +/- 6% relative to baseline (air) due to vasoconstriction. Hypercapnia (5% CO2 + 21% O-2) increased blood flow 16 +/- 6% due to vasodilation. Increasing isoflurane (a potent vasodilator) concentration to 1.5% increased blood flow to 9.3 +/- 2.7 ml/g/min. Blood-flow signals were confirmed to be genuine by repeating measurements after the animals were sacrificed in the MRI scanner. This study demonstrates a proof of concept that quantitative blood flow of the retina can be measured using MRI without depth limitation. Blood-flow MRI has the potential to provide unique insights into retinal physiology, serve as an early biomarker for some retinal diseases, and could complement optically based imaging techniques. (C) 2007 Elsevier Inc. All rights reserved.