Magnetic resonance imaging of the retina

Duong, Timothy Q.; Muir, Eric R.

doi:10.1007/s10384-009-0688-1

Cited by 60 publications

(86 citation statements)

References 74 publications

(101 reference statements)

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“…Recent advances in MR imaging make it possible to more closely examine the interface between anatomic disruption and physiologic dysfunction. 36 [40][41][42][43][44] fMRI has been used in mapping the function of cortical regions in a variety of healthy and disease states involving vision. 45,46 In cases involving papilledema, fMRI of the visual pathway and particularly the retina may offer insight into the effect of papilledema on visual impairment.…”

Section: Future Directions Of Mr Imaging In Papilledema Imagingmentioning

confidence: 99%

“…Retinal fMRI is still in the early stages of development and is currently performed only in animal models, still well below the resolution of optical imaging techniques. [47][48][49] These animal experiments have already shown promise in imaging the activity of the retina in response to visual stimuli 50 and can distinguish the 2 retinal layers supplied by the retinal and choroidal arteries with differing responses to hypercapnia and hyperoxia. 51 fMRI has been shown to detect retinal damage by evaluating decreased basal blood flow in rats.…”

Section: Future Directions Of Mr Imaging In Papilledema Imagingmentioning

confidence: 99%

See 1 more Smart Citation

MR Imaging of Papilledema and Visual Pathways: Effects of Increased Intracranial Pressure and Pathophysiologic Mechanisms

Passi

Degnan

Levy

2012

AJNR Am J Neuroradiol

105

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SUMMARY: Papilledema, defined as swelling of the optic disc, frequently occurs in the setting of increased ICP and in a variety of medical conditions, including pseudotumor cerebri, sinus thrombosis, intracerebral hemorrhage, frontal lobe neoplasms, and Chiari malformation. Noninvasive imaging of the ON is possible by using MR imaging, with a variety of findings occurring in the setting of papilledema, including flattening of the posterior sclera, protrusion of the optic disc, widening of the ONS, and tortuosity of the ON. Early recognition of papilledema and elevated ICP is of paramount importance for ensuring restoration of vision. Newer advanced MR imaging techniques such as fMRI and DTI may prove useful in the future to assess the potential effects of papilledema on retinal and visual pathway integrity.ABBREVIATIONS: ICP ϭ intracranial pressure; IIH ϭ idiopathic intracranial hypertension; ON ϭ optic nerve; ONS ϭoptic nerve sheath; SAS ϭ subarachnoid space

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Section: Future Directions Of Mr Imaging In Papilledema Imagingmentioning

confidence: 99%

Section: Future Directions Of Mr Imaging In Papilledema Imagingmentioning

confidence: 99%

MR Imaging of Papilledema and Visual Pathways: Effects of Increased Intracranial Pressure and Pathophysiologic Mechanisms

Passi

Degnan

Levy

2012

AJNR Am J Neuroradiol

105

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“…Physiologically evoked changes in blood flow were recently reported by laser speckle imaging with large FOV (Cheng and Duong, 2007). Physiologically evoked and visually evoked (Duong et al, 2002) changes of blood oxygenation in the retina can be detected by BOLD functional MRI.…”

Section: Imaging Vascular Reactivitymentioning

confidence: 99%

“…Advances in MRI technologies over the past decade have significantly improved spatial resolution and sensitivity. MRI has recently been applied to investigate structures of the retina (Berkowitz et al, 2006;Cheng et al, 2006;Shen et al, 2006), as well as changes in tissue oxygenation using blood-oxygen-level-dependent (BOLD) functional MRI associated with physiologic and visual (Duong et al, 2002) stimulation in the retina. Changes in layer thickness and BOLD functional MRI responses to physiologic challenges in an animal model of retinitis pigmentosa in which the photoreceptors progressively degenerate have also been reported .…”

Section: Introductionmentioning

confidence: 99%

Blood-flow magnetic resonance imaging of the retina

Cheng

Duong

2008

NeuroImage

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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 90×90×1500-μm 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% CO 2 +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. Bloodflow 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.

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“…There are promising new noninvasive technologies that measure retinal oxygen concentration indirectly, including those based on magnetic resonance [12], [17] and spectral imaging [18], [19], but they cannot yet provide a quantitative measure of oxygen concentration within the retinal tissue affected by disease. Although another method utilizing phosphorescence is proposed in [13], it requires injecting phosphorescence dyes directly into the eye cavity.…”

Section: A Prior Work In Measuring Intraocular Oxygen Concentrationmentioning

confidence: 99%

A Magnetically Controlled Wireless Optical Oxygen Sensor for Intraocular Measurements

et al. 2008

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Abstract-The influence of oxygen on various ophthalmological complications is not completely understood and intraocular oxygen measurements are essential for better diagnosis and treatment. A magnetically controlled wireless sensor device is proposed for minimally invasive intraocular oxygen concentration measurements. This device will make it possible to make measurements at locations that are currently too invasive for human intervention by integrating a luminescence optical sensor and a magnetic steering system. The sensor works based on quenching of luminescence in the presence of oxygen. A novel iridium phosphorescent complex is designed and synthesized for this system. A frequency-domain lifetime measurement approach is employed because of the intrinsic nature of the lifetime of luminescence. Experimental results of the oxygen sensor together with magnetic and hydrodynamic characterization of the sensor platform are presented to demonstrate the concept. In order to use this sensor for in vivo intraocular applications, the size of the sensor must be reduced, which will require an improved signal-to-noise ratio.

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Magnetic resonance imaging of the retina

Cited by 60 publications

References 74 publications

MR Imaging of Papilledema and Visual Pathways: Effects of Increased Intracranial Pressure and Pathophysiologic Mechanisms

MR Imaging of Papilledema and Visual Pathways: Effects of Increased Intracranial Pressure and Pathophysiologic Mechanisms

Blood-flow magnetic resonance imaging of the retina

A Magnetically Controlled Wireless Optical Oxygen Sensor for Intraocular Measurements

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