System and method for examining an illuminated object
View Patent ↗In a system and a method for examining an object containing a fluid liquid, the object is illuminated with measuring light and images are temporarily shortly subsequently recorded. The images are evaluated per pixel to determine perfusion data from a high frequency portion above 1 kHz and to determine further information about properties of the object from a low frequency portion below 100 Hz, such as a degree of oxygenation of hemoglobin, a concentration of hemoglobin or a concentration of ICG. This information determined by evaluation is displayed in a form of an image in superposition with a white light image of the object.
1. A method for examining an object containing a flowing liquid, the method comprising:
illuminating the object with measuring light and recording at least one sequence of first images (I k (i,j); k=1, . . . , N) of the illuminated object, wherein an exposure time for each recording of an image of the at least one sequence of first images (I k (i,j); k=1, . . . , N) is smaller than 1 ms;
evaluating, with an evaluation system, the at least one sequence of first images (I k (i,j); k=1, . . . , N) by associating pixels (i,j) in the at least one sequence of first images (I k (i,j); k=1, . . . , N) to which same locations (x,y) of the object are imaged with a first analysis image value, respectively, wherein the first analysis image value depends on fluctuations of image values (I(t,i,j)) of the pixels (i,j) in the at least one sequence of first images (I k (i,j); k=1, . . . , N) in a frequency range above 1 kHz; and
evaluating, with the evaluation system, the at least one sequence of first images (I k (i,j); k=1, . . . , N), by further associating pixels (i,j) in the at least one sequence of first images (I k (i,j); k=1, . . . , N) to which same locations (x,y) of the object are imaged with a second analysis image value, respectively, wherein the second analysis image value depends on fluctuations of image values (I(t,i,j)) of the pixels (i,j) in the at least one sequence of first images (I k (i,j); k=1, . . . , N) in a frequency range below 100 Hz, wherein the measuring light illuminating the object comprises wavelengths in a measuring light wavelength range from one of 605 nm to 630 nm, 560 nm to 580 nm, and 794 nm to 814 nm, and wherein the recording the at least one sequence of first images comprises detecting measuring light, wherein a ratio of an intensity of the detected measuring light having wavelengths outside the measuring light wavelength range from a total intensity of the detected measuring light amounts to less than 10%,
wherein the evaluation system comprises a processing system including a computer.
2. The method according to claim 1 , wherein the recording the at least one sequence of first images (I k (i,j); k=1, . . . , N) comprises recording temporally subsequent images with a temporal interval of smaller than 1 ms.
3. The method according to claim 1 , wherein the measuring light has a coherence length corresponding at least to twice a penetration depth of the measuring light into the object.
4. The method according to claim 1 , further comprising: illuminating the object with white light; and imaging and detecting the object illuminated with white light to determine a white light image of the object.
5. The method according to claim 1 , wherein the first analysis image value associated with a pixel represents a value comprises one of a perfusion, a concentration, an average velocity, a measure for a velocity distribution, in particular a standard deviation of the velocity distribution, of particles moving relative to each other, in particular blood cells, and a combination of the same.
6. The method according to claim 1 , further comprising at least one of displaying, in particular in superposition, and storing at least one of the first images, the first analysis image values, the second analysis image values, and the white light image for a plurality of pixels.
7. The method according to claim 1 , further comprising repeating the recording the at least one sequence of first images (I k (i,j); k=1, . . . , N) as temporal sequence and respective evaluating the repeatedly recorded at least one sequence of first images (I k (i,j); k=1, . . . , N).
8. The method according to claim 1 , wherein the object is part of a brain of a patient, in particular an aneurysm in the head of the patient.
9. The method according to claim 1 , further comprising stimulating the patient.
10. The method according to claim 1 , further comprising displaying a region of the object in dependence of a result of comparing of at least one of the first analysis image value, the second analysis image value, and an image value of at least one second image to preset threshold values for pixels to which the region of the object is imaged.
11. A method for examining an object containing a flowing liquid, the method comprising:
illuminating the object with measuring light and recording at least one sequence of first images (I k (i,j); k=1, . . . , N) of the illuminated object, wherein an exposure time for each recording of an image of the at least one sequence of first images (I k (i,j); k=1, . . . , N) is smaller than 1 ms;
evaluating, with an evaluation system, the at least one sequence of first images (I k (i,j); k=1, . . . , N) by associating pixels (i,j) in the at least one sequence of first images (I k (i,j); k=1, . . . , N) to which same locations (x,y) of the object are imaged with a first analysis image value, respectively, wherein the first analysis image value depends on fluctuations of image values (I(t,i,j)) of the pixels (i,j) in the at least one sequence of first images (I k (i,j); k=1, . . . , N) in a frequency range above 1 kHz; and
evaluating, with the evaluation system, the at least one sequence of first images (I k (i,j); k=1, . . . , N), by further associating pixels (i,j) in the at least one sequence of first images (I k (i,j); k=1, . . . , N) to which same locations (x,y) of the object are imaged with a second analysis image value, respectively, wherein the second analysis image value depends on fluctuations of image values (I(t,i,j)) of the pixels (i,j) in the at least one sequence of first images (I k (i,j); k=1, . . . , N) in a frequency range below 100 Hz, wherein the recording the at least one sequence of first images comprises detecting measuring light, wherein a ratio of an intensity of the detected measuring light having wavelengths greater than 850 nm and smaller than 500 nm from a total intensity of the detected measuring light amounts to less than 10%,
wherein the evaluation system comprises a processing system including a computer.
12. The method according to claim 11 , wherein the measuring light has a coherence length corresponding at least to twice a penetration depth of the measuring light into the object.
13. The method according to claim 11 , further comprising: illuminating the object with white light; and imaging and detecting the object illuminated with white light to determine a white light image of the object.
14. The method according to claim 11 , wherein the first analysis image value associated with a pixel represents a value comprises one of a perfusion, a concentration, an average velocity, a measure for a velocity distribution, in particular a standard deviation of the velocity distribution, of particles moving relative to each other, in particular blood cells, and a combination of the same.
15. The method according to claim 11 , further comprising at least one of displaying, in particular in superposition, and storing at least one of the first images, the first analysis image values, the second analysis image values, and the white light image for a plurality of pixels.
16. The method according to claim 11 , further comprising repeating the recording the at least one sequence of first images (I k (i,j); k=1, . . . , N) as temporal sequence and respective evaluating the repeatedly recorded at least one sequence of first images (I k (i,j); k=1, . . . , N).
17. The method according to claim 11 , wherein the object is part of a brain of a patient, in particular an aneurysm in the head of the patient.
18. The method according to claim 11 , further comprising stimulating the patient.
19. The method according to claim 11 , further comprising displaying a region of the object in dependence of a result of comparing of at least one of the first analysis image value, the second analysis image value, and an image value of at least one second image to preset threshold values for pixels to which the region of the object is imaged.
20. The method according to claim 11 , wherein the recording the at least one sequence of first images (I k (i,j); k=1, . . . , N) comprises recording temporally subsequent images with a temporal interval of smaller than 1 ms.