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Pharmacological MRI of the choroid and retina: Blood flow and BOLD responses during nitroprusside infusion
Author(s) -
Shih YenYu I.,
Li Guang,
Muir Eric R.,
De La Garza Bryan H.,
Kiel Jeffrey W.,
Duong Timothy Q.
Publication year - 2012
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.24112
Subject(s) - nitric oxide , blood flow , choroid , retina , hemodynamics , vasodilation , medicine , anesthesia , oxygenation , sodium nitroprusside , magnetic resonance imaging , cardiology , psychology , neuroscience , radiology
Nitroprusside, a vasodilatory nitric oxide donor, is clinically used during vascular surgery and to lower blood pressure in acute hypertension. This article reports a novel application of blood flow (BF) and blood oxygenation level dependent (BOLD) MRI on an 11.7T scanner to image the rat chorioretinal BF and BOLD changes associated with graded nitroprusside infusion. At low doses (1 or 2 μg/kg/min), nitroprusside increased BF as expected but decreased BOLD signals, showing an intriguing BF–BOLD uncoupling. At high doses (3−5 μg/kg/min), nitroprusside decreased BF and markedly decreased BOLD signals. To our knowledge, this is the first pharmacological MRI application of the retina. This approach has potential to open up new avenues to study the drug‐related hemodynamic functions and to evaluate the effects of novel therapeutic interventions on BOLD and BF in the normal and diseased retinas. Magn Reson Med, 2012. © 2011 Wiley Periodicals, Inc.