Blood Flow Magnetic Resonance Imaging of Retinal Degeneration
Blood Flow Magnetic Resonance Imaging of Retinal Degeneration
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DOI：
10.1167/iovs.08-2188
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发表时间：
2009-04-01
影响因子：
4.4
通讯作者：
Duong, Timothy Q.
中科院分区：
文献类型：
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作者：
Li, Yingxia;Cheng, Haiying;Duong, Timothy Q.
目的.本研究旨在探讨定量基础血流量以及高碳酸血症和高氧诱导的视网膜血流变化的皇家外科学院（RCS）大鼠自发性视网膜变性，并与正常大鼠视网膜进行比较。在出生后第90天（n = 4）和第220天（n = 5）对雄性RCS大鼠进行实验，并在出生后第90天（n = 7）和第220天（n = 6）对年龄匹配的对照组进行实验。高氧（100%O-2）和高碳酸（5%CO2，21%O-2，平衡N-2）挑战用于调节血流。定量基线血流量，高碳酸血症和高氧诱导的视网膜血流量的变化进行了成像，使用连续动脉自旋标记MRI在90 × 90 × 1500 μ m. MTS。在正常大鼠视网膜中，整个视网膜的基础血流量为5.5 mL/g/min，显著高于大脑中报告的血流量（类似于1 mL/g/min）。在正常视网膜中，高氧会由于血管收缩而减少血流量，而高碳酸血症会由于血管舒张而增加血流量。RCS大鼠视网膜基础血流量明显减少（P < 0.05）。有趣的是，RCS视网膜中绝对高氧和高碳酸诱导的血流变化与正常视网膜中的血流变化无统计学差异（P > 0.05）。然而，由于RCS视网膜的基础血流量较低，RCS视网膜的血流量百分比变化显着大于正常视网膜。结论。视网膜变性明显减少基础血流量，但似乎不损害血管反应性。这些数据也表明谨慎解释相对刺激诱发的功能性MRI变化的基础参数显着扰动的疾病状态。定量血流MRI可以作为一个有价值的工具，研究视网膜没有深度限制。（Invest Ophthalmol维斯科学。2009; 50：1824-1830）DOI：10.1167/iovs.08-2188
PURPOSE. This study aims to investigate quantitative basal blood flow as well as hypercapnia- and hyperoxia-induced blood flow changes in the retinas of the Royal College of Surgeons (RCS) rats with spontaneous retinal degeneration, and to compare with those of normal rat retinas.METHODS. Experiments were performed on male RCS rats at post-natal days P90 (n = 4) and P220 (n = 5), and on age-matched controls at P90 (n = 7) and P220 (n = 6). Hyperoxic (100% O-2) and hypercapnic (5% CO2, 21% O-2, balance N-2) challenges were used to modulate blood flow. Quantitative baseline blood flow, and hypercapnia- and hyperoxia-induced blood flow changes in the retinas were imaged using continuous arterial spin labeling MRI at 90 x 90 x 1500 mu m.RESULTS. In the normal rat retinas, basal blood flow of the whole-retina was 5.5 mL/gram per min, significantly higher than those reported in the brain (similar to 1 mL/gram per min). Hyperoxia decreased blood flow due to vasoconstriction and hypercapnia increased blood flow due to vasodilation in the normal retinas. In the RCS rat retinas, basal blood flow was diminished significantly (P < 0.05). Interestingly, absolute hyperoxia- and hypercapnia- induced blood flow changes in the RCS retinas were not statistically different from those in the normal retinas (P > 0.05). However, blood flow percent changes in RCS retinas were significantly larger than in normal retinas due to lower basal blood flow in the RCS retinas.CONCLUSIONS. Retinal degeneration markedly reduces basal blood flow but does not appear to impair vascular reactivity. These data also suggest caution when interpreting relative stimulus-evoked functional MRI changes in diseased states where basal parameters are significantly perturbed. Quantitative blood flow MRI may serve as a valuable tool to study the retina without depth limitation. (Invest Ophthalmol Vis Sci. 2009; 50: 1824-1830) DOI:10.1167/iovs.08-2188