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Alexander Foster, Chieh-Li Chen, Qinqin Zhang, Ruikang K Wang, Raghu C Mudumbai; Correlating fundus photography and optical coherence tomography-based microangiography (OMAG) in patients with papilledema.. Invest. Ophthalmol. Vis. Sci. 2016;57(12):4543.
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© ARVO (1962-2015); The Authors (2016-present)
OMAG is a novel imaging technique capable of producing quantifiable, three-dimensional images of perfusion within microcirculatory tissue beds without dye, as is used in fluorescein angiography (FA). There currently is no data regarding OMAG characteristics of papilledema (PE). PE occasionally requires diagnostic imaging with FA. We wished to identify features of papilledema on OMAG through correlation with fundus photographs, and investigate its clinical utility in diagnosing this condition since it has potential advantages over FA.
6 patients with PE, all from idiopathic intracranial hypertension, were identified. They underwent FP and OMAG imaging. Subjects were scanned using a 68 kHz Cirrus HD-OCT 5000 based OMAG prototype system (Zeiss, Dublin, CA) covering a 6.7x6.7 mm2 area centered at the optic nerve head (ONH) (9.8 µm sampling resolution). rNFL vascular en face images were generated along the axial direction. Two patients underwent concomitant FA. FP were clinically characterized using the Freisen scale and the extent of peripapillary rNFL axonal swelling present. These findings were then correlated to OMAG imaging of the peripapillary region performed on the same day.
Freisen scores ranged from 1 to 4 with varying degrees of rNFL edema. OMAG consistently demonstrated circumferential dropout of the peripapillary rNFL vasculature in all patients (figure 1), absent in normal controls. This feature was present even in low-grade cases of disc edema. Large vessel detail was obscured in areas of rNFL edema on OMAG, consistent with prior descriptions. OMAG required good central vision (GCV) to obtain high quality images.
This is the first effort to clinically characterize the OMAG imaging appearance of optic nerve head swelling found in PE. The most consistent OMAG feature of PE was a circumferential ring of rNFL microvasculature dropout. We postulate that this imaging characteristic is a result of reduced vascular density secondary to peripapillary transudate. This feature was well-visualized even in very mild (Freisen 1) cases of PE, which may make OMAG a useful clinical adjunct to diagnosing subtle disease states, especially as it does not require contrast dye. OMAG does require GCV for to obtain quality images.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
OMAG of the optic nerve of a patient with papilledema. Red arrow: peripapillary vascular dropout.
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