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Anatomical, blood oxygenation level‐dependent, and blood flow MRI of nonhuman primate (baboon) retina
Author(s) -
Zhang Yi,
Wey HsiaoYing,
Nateras Oscar San Emeterio,
Peng Qi,
De La Garza Bryan H.,
Duong Timothy Q.
Publication year - 2011
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.22853
Subject(s) - retina , baboon , blood flow , retinal , choroid , oxygenation , anatomy , magnetic resonance imaging , primate , non human primate , biology , medicine , pathology , biomedical engineering , ophthalmology , neuroscience , radiology , evolutionary biology
The goal of this study was to demonstrate high‐resolution anatomical, blood oxygenation level‐dependent, and blood flow MRI on large nonhuman primate retinas using a 3‐Tesla clinical scanner as a first step toward translation. Baboon was chosen because of its evolutionary similarity to human. Anesthetized preparation, free of eye‐movement artifacts, was used to evaluate clinical scanner hardware feasibility and optimize multimodal protocols for retinal MRI. Anatomical MRI (0.1 × 0.2 × 2.0 mm 3 ) before contrast‐agent injection detected three alternating bright–dark–bright layers. The hyperintense inner strip nearest to the vitreous was enhanced by an intravascular contrast agent, which likely included the ganglion and bipolar cell layer and the embedded retinal vessels. The hypointense middle strip showed no contrast enhancement, which likely included the avascular outer unclear layer and photoreceptor segments. The hyperintense outer strip showed contrast enhancement, which likely corresponded to the choroid vascular layer. In the posterior retina, the total thickness including the choroid was 617 ± 101 μm (± standard deviation, n = 7). Blood oxygenation level‐dependent functional MRI (0.3 × 0.6 × 2.0 mm 3 ) of oxygen inhalation relative to air increased the signals by 6.5 ± 1.4%. Basal blood flow (2 × 2 × 2 mm 3 ) was 83 ± 30 mL/100 g/min (air), and hypercapnia increased blood flow by 25 ± 9% ( P < 0.05). This study demonstrates multimodal MRI to image anatomy, physiology, and function on large nonhuman primate retinas using a clinical scanner, offering encouraging data to explore human applications. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.