초록 ▼

Real time, high-speed image stabilization with a retinal tracking scanning laser ophthalmoscope (TSLO) enables new approaches to established diagnostics. Large frequency range (DC to 19 kHz), wide-field (40-deg) stabilized Doppler flowmetry imaging is described for human subjects. The fundus imaging

Real time, high-speed image stabilization with a retinal tracking scanning laser ophthalmoscope (TSLO) enables new approaches to established diagnostics. Large frequency range (DC to 19 kHz), wide-field (40-deg) stabilized Doppler flowmetry imaging is described for human subjects. The fundus imaging method is a quasi-confocal line-scanning laser ophthalmoscope (LSLO). The retinal tracking system uses a confocal reflectometer with a closed loop optical servo system to lock onto features in the ocular fundus and automatically re-lock after blinks. By performing a slow scan with the laser line imager, frequency-resolved retinal perfusion and vascular flow images can be obtained free of eye motion artifacts.

대표청구항 ▼

What is claimed: 1. A method of monitoring blood flow in a retina, comprising: illuminating the retina with a line of light at a first position and a second position; recording a first plurality of images of the line of light on the retina at the first position and a second plurality of images of t

What is claimed: 1. A method of monitoring blood flow in a retina, comprising: illuminating the retina with a line of light at a first position and a second position; recording a first plurality of images of the line of light on the retina at the first position and a second plurality of images of the line of light on the retina at the second position, each of the first plurality of images recorded at a first set of successive time periods to form a first spatial-temporal image plane and each of the second plurality of images recorded at a second set of successive time periods to form a second spatial-temporal image plane; and combining the first spatial-temporal image plane and the second spatial-temporal image plane to form a three-dimensional image of the retina, wherein one dimension is a temporal dimension including a time varying signal representing the flow of blood in the retina. 2. The method of claim 1 wherein each of the spatial-temporal image planes has N spatial pixels captured simultaneously in the line of light at N successive time periods. 3. The method of claim 2 further comprising illuminating the retina with the line of light at N positions to form N spatial-temporal image planes. 4. The method of claim 3 further comprising combining the N spatial-temporal image planes to form an image cube of the retina with dimensions of N��N��N. 5. The method of claim 1 wherein recording a respective plurality of images comprises confocally receiving with a linear array detector light reflected from the portion of the retina illuminated with the line of light. 6. The method of claim 1 further comprising performing a Fourier transform of the three-dimensional image of the retina to extract a power spectrum of each image pixel. 7. The method of claim 6 wherein the power spectrum comprises a AC portion representing blood flow and a DC portion representing average image brightness. 8. The method of claim 7 further comprising normalizing the power spectrum by the DC values to remove variability across a respective plurality of images due to intensity of the line of light or reflectivity of an imaged volume of tissue. 9. The method of claim 6 further comprising binning portions of the power spectrum according to a frequency range. 10. The method of claim 9 wherein a low frequency bin represents perfusion through the micro-vasculature of the retina. 11. The method of claim 9 wherein a middle frequency bin represents blood flow in small retinal vessels. 12. The method of claim 9 wherein a high frequency bin represents blood flow in large retinal vessels. 13. The method of claim 9 further comprising combining a plurality of frequency bins to form a video of blood flow and vessel pattern. 14. The method of claim 6 further comprising scaling binned portions of the power spectrum. 15. The method of claim 14 further comprising scaling binned portions to form a normalized spectrum to compare blood flow in a first patient and blood flow in a second patient. 16. The method of claim 14 further comprising scaling binned portions to form a normalized stretched spectrum to compare blood flow in a patient at a first time and blood flow in the same patient at a second time. 17. An apparatus for monitoring blood flow in a retina, comprising: a retinal tracking device for locking onto a feature of the retina; a line-scanning laser ophthalmoscope for illuminating the retina with a line of light at a first position and at a second position, including a linear array detector for confocally receiving a first plurality of images of the line of light on the retina at the first position for a first set of successive time periods and a second plurality of images of the line of light on the retina at the second position for a second set of successive time periods; and a processor for forming a first spatial-temporal image plane from the first plurality of images of the line of light on the retina at the first position versus the first set of successive time periods, forming a second spatial-temporal image plane from the second plurality of images of the line of light on the retina at the second position versus the second set of successive time periods, and combining the first spatial-temporal image plane and the second spatial-temporal image plane to form a three-dimensional image of the retina, wherein one dimension is a temporal dimension including a time varying signal representing the flow of blood in the retina. 18. The apparatus of claim 17 wherein each of the spatial-temporal image planes has N spatial pixels captured simultaneously in the line of light at N successive time periods. 19. The apparatus of claim 18 wherein the retina is illuminated with the line of light at N positions to form N spatial-temporal image planes. 20. The apparatus of claim 19 wherein the processor combines the N spatial-temporal image planes to form an image cube of the retina with dimensions of N��N��N. 21. The apparatus of claim 17 wherein the processor performs a Fourier transform of the three-dimensional image of the retina to extract a power spectrum of each image pixel. 22. The apparatus of claim 17 wherein the retinal tracking device comprises a confocal reflectometer with a closed loop servo system to look onto a feature of the fundus of the retina. 23. The apparatus of claim 17 wherein the retinal tracking device locks a tracking beam onto a retinal feature and processes the backreflected signal from the tracking beam to stabilize the line-scanning laser ophthalmoscope. 24. The apparatus of claim 17 wherein the retinal tracking device tracks at a rate that exceeds the maximum rate of motion of an eye. 25. The apparatus of claim 24 wherein the retinal tracking device comprises a bandwidth of greater than 1 kHz. 26. The apparatus of claim 17 wherein the retinal tracking device improves the resolution of the line-scanning laser ophthalmoscope. 27. An apparatus for monitoring blood flow in a retina, comprising: a means for illuminating the retina with a line of light at a first position and a second position; a means for recording a first plurality of images of the line of light on the retina at the first position and a second plurality of images of the line of light on the retina at the second position, each of the first plurality of images recorded at successive time periods to form a first spatial-temporal image plane and each of the second plurality of images recorded at a respective time period to form a second spatial-temporal image plane; and a means for combining the first spatial-temporal image plane and the second spatial-temporal image plane to form a three-dimensional image of the retina, wherein one dimension is a temporal dimension including a time varying signal representing the flow of blood in the retina.