The Experts below are selected from a list of 30 Experts worldwide ranked by ideXlab platform
Timothy Q. Duong - One of the best experts on this subject based on the ideXlab platform.
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balanced steady state free precession for arterial spin labeling mri initial experience for Blood Flow mapping in human brain Retina and kidney
Magnetic Resonance Imaging, 2013Co-Authors: Danny J J Wang, Sunghong Park, Timothy Q. DuongAbstract:article i nfo We implemented pseudo-continuous ASL (pCASL) with 2D and 3D balanced steady state free precession (bSSFP) readout for mapping Blood Flow in the human brain, Retina, and kidney, free of distortion and signal dropout, which are typically observed in the most commonly used echo-planar imaging acquisition. High resolution functional brain imaging in the human visual cortex was feasible with 3D bSSFP pCASL. Blood Flow of the human Retina could be imaged with pCASL and bSSFP in conjunction with a phase cycling approach to suppress the banding artifacts associated with bSSFP. Furthermore, bSSFP based pCASL enabled us to map renal Blood Flow within a single breath hold. Control and test-retest experiments suggested that the measured Blood Flow values in Retina and kidney were reliable. Because there is no specific imaging tool for mapping human Retina Blood Flow and the standard contrast agent technique for mapping renal Blood Flow can cause problems for patients with kidney dysfunction, bSSFP based pCASL may provide a useful tool for the diagnosis of Retinal and renal diseases and can complement existing imaging techniques.
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Pharmacological MRI of the choroid and Retina: Blood Flow and BOLD responses during nitroprusside infusion.
Magnetic resonance in medicine, 2011Co-Authors: Yen Yu Ian Shih, Eric R. Muir, Bryan H. De La Garza, Jeffrey W. Kiel, Timothy Q. DuongAbstract: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.
Raul Velez-montoya - One of the best experts on this subject based on the ideXlab platform.
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Changes in Retinal and Choroidal Vascular Blood Flow after Oral Sildenafil: An Optical Coherence Tomography Angiography Study
Journal of ophthalmology, 2017Co-Authors: David Berrones, Guillermo Salcedo-villanueva, Virgilio Morales-canton, Raul Velez-montoyaAbstract:Purpose. To describe changes in the Retina and choroidal Flow by optical coherence tomography angiography (OCT-A) after a single dose of oral sildenafil. Method. A case-control study. Patients in the study group received 50 mg of oral sildenafil. Patients in the control group received a sham pill. Retinal and choroidal images were obtained at baseline (before pill ingestion) and 1 hour after ingestion. Central macular and choroidal thickness, choroidal and outer Retina Flow, and the Retinal and choroidal vascular density were compared using a Mann-Whitney U test. Results. Twenty eyes were enrolled into the study group and 10 eyes in the control group. There was a significant difference in central choroidal thickness and outer Retina Blood Flow between groups after 1 hour of sildenafil ingestion ( ). There were no differences in central macular thickness, choroidal Flow, and Retinal vascular density among groups. Conclusions. A single dose of oral sildenafil increases choroidal thickness, probably due to sildenafil-induced vasodilation.
David Berrones - One of the best experts on this subject based on the ideXlab platform.
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Changes in Retinal and Choroidal Vascular Blood Flow after Oral Sildenafil: An Optical Coherence Tomography Angiography Study
Journal of ophthalmology, 2017Co-Authors: David Berrones, Guillermo Salcedo-villanueva, Virgilio Morales-canton, Raul Velez-montoyaAbstract:Purpose. To describe changes in the Retina and choroidal Flow by optical coherence tomography angiography (OCT-A) after a single dose of oral sildenafil. Method. A case-control study. Patients in the study group received 50 mg of oral sildenafil. Patients in the control group received a sham pill. Retinal and choroidal images were obtained at baseline (before pill ingestion) and 1 hour after ingestion. Central macular and choroidal thickness, choroidal and outer Retina Flow, and the Retinal and choroidal vascular density were compared using a Mann-Whitney U test. Results. Twenty eyes were enrolled into the study group and 10 eyes in the control group. There was a significant difference in central choroidal thickness and outer Retina Blood Flow between groups after 1 hour of sildenafil ingestion ( ). There were no differences in central macular thickness, choroidal Flow, and Retinal vascular density among groups. Conclusions. A single dose of oral sildenafil increases choroidal thickness, probably due to sildenafil-induced vasodilation.
Guillermo Salcedo-villanueva - One of the best experts on this subject based on the ideXlab platform.
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Changes in Retinal and Choroidal Vascular Blood Flow after Oral Sildenafil: An Optical Coherence Tomography Angiography Study
Journal of ophthalmology, 2017Co-Authors: David Berrones, Guillermo Salcedo-villanueva, Virgilio Morales-canton, Raul Velez-montoyaAbstract:Purpose. To describe changes in the Retina and choroidal Flow by optical coherence tomography angiography (OCT-A) after a single dose of oral sildenafil. Method. A case-control study. Patients in the study group received 50 mg of oral sildenafil. Patients in the control group received a sham pill. Retinal and choroidal images were obtained at baseline (before pill ingestion) and 1 hour after ingestion. Central macular and choroidal thickness, choroidal and outer Retina Flow, and the Retinal and choroidal vascular density were compared using a Mann-Whitney U test. Results. Twenty eyes were enrolled into the study group and 10 eyes in the control group. There was a significant difference in central choroidal thickness and outer Retina Blood Flow between groups after 1 hour of sildenafil ingestion ( ). There were no differences in central macular thickness, choroidal Flow, and Retinal vascular density among groups. Conclusions. A single dose of oral sildenafil increases choroidal thickness, probably due to sildenafil-induced vasodilation.
Virgilio Morales-canton - One of the best experts on this subject based on the ideXlab platform.
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Changes in Retinal and Choroidal Vascular Blood Flow after Oral Sildenafil: An Optical Coherence Tomography Angiography Study
Journal of ophthalmology, 2017Co-Authors: David Berrones, Guillermo Salcedo-villanueva, Virgilio Morales-canton, Raul Velez-montoyaAbstract:Purpose. To describe changes in the Retina and choroidal Flow by optical coherence tomography angiography (OCT-A) after a single dose of oral sildenafil. Method. A case-control study. Patients in the study group received 50 mg of oral sildenafil. Patients in the control group received a sham pill. Retinal and choroidal images were obtained at baseline (before pill ingestion) and 1 hour after ingestion. Central macular and choroidal thickness, choroidal and outer Retina Flow, and the Retinal and choroidal vascular density were compared using a Mann-Whitney U test. Results. Twenty eyes were enrolled into the study group and 10 eyes in the control group. There was a significant difference in central choroidal thickness and outer Retina Blood Flow between groups after 1 hour of sildenafil ingestion ( ). There were no differences in central macular thickness, choroidal Flow, and Retinal vascular density among groups. Conclusions. A single dose of oral sildenafil increases choroidal thickness, probably due to sildenafil-induced vasodilation.