ISSN:
1573-9686
Keywords:
Retinal vessels
;
Fluorescein angiography
;
Shear
;
Hematocrit
;
Yield of fluorescence
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
,
Technology
Notes:
Abstract The purpose of this work was to obtain more quantitative knowledge about the yield of fluorescence from retinal vessels during fluorescein angiography. The influence of shear rate, concentration of sodium fluorescein, hematocrit, and layer thickness on the yield of fluorescence from blood were investigated. Measurements were performedin vitro on samples of human blood in a cone-plate shear chamber using frontal illumination. Application of physiologically relevant levels of shear (〉88/sec) decreased the yield of fluorescence from the blood sample considerably as compared with stasis. The yield of fluorescence was proportionally related to the logarithm of the sodium fluorescein concentration in blood up to a sodium fluorescein concentration of 1.2 mg/ml. Above that concentration quenching occurred. An increase in layer thickness at a hematocrit of 45% resulted only in an increase of the yield of fluorescence up to a layer thickness of 25 μm. In conclusion, the sodium fluorescein concentration in blood is the only important factor that determines the yield of fluorescence from the larger retinal vessels in the successive phases of the fluorescein angiogram in a subject with a given hematocrit and hemoglobin concentration. The yield of fluorescence from retinal vessels (〉25 μm) is proportionally related to the logarithm of the sodium fluorescein concentration over a broad range of concentrations.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02367082
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