Intralipid as a contrast agent to enhance subsurface blood flow imaging

1. A method of distinguishing between different types of animal microvasculature in an animal, comprising:

(i) injecting a lipid solution into a bloodstream of the animal;

(ii) performing a plurality of imaging scans of microvasculature of the animal using Optical Doppler Tomography (ODT);

(iii) determining a Doppler shift produced by the lipid solution based on the imaging scans;

(iv) calculating a blood flow velocity and a blood flow direction in the microvasculature based on the Doppler shift; and

(v) distinguishing between different types of the animal microvasculature based on the blood flow velocity and the blood flow direction.

2. The method of claim 1 , wherein the lipid solution includes at least one of a fat emulsion, a total parenteral nutrition solution, a parental nutrition solution, or a total peripheral nutrition solution.

3. The method of claim 2 , wherein the at least one of the fat emulsion, the total parenteral nutrition solution, the parental nutrition solution, or the total peripheral nutrition solution is a contrast agent.

4. The method of claim 2 , further comprising generating a three-dimensional image of the microvasculature.

5. The method of claim 2 , wherein the fat emulsion has a fat concentration of at least one of 10%, 20% or 30%.

6. The method of claim 1 , wherein the lipid solution is a contrast agent.

7. The method of claim 1 , wherein the animal is a mammal.

8. The method of claim 7 , wherein the mammal is a human.

9. The method of claim 1 , wherein the distinguishing between different types of animal microvasculature includes distinguishing a tumor microvasculature from a non-tumor microvasculature.

10. The method of claim 9 , wherein the tumor is a glioblastoma multiforme.

11. The method of claim 1 , wherein the Doppler shift is a continuous Doppler shift.

12. The method of claim 1 , further comprising:

determining a backscattering of a light produced by the lipid solution based on the imaging scans; and

calculating the blood flow velocity and the blood flow direction in capillaries based on the Doppler shift and the backscattering of the light.

13. A method of distinguishing between different types of animal microvasculature comprising:

(i) injecting a lipid solution into a bloodstream of an animal;

(ii) performing a plurality of imaging scans of microvasculature of the animal using Optical Doppler Tomography (ODT);

(iii) determining a Doppler shift produced by the lipid solution based on the imaging scans;

(iv) calculating a blood flow velocity and a blood flow direction in the microvasculature based on the Doppler shift;

(v) quantitatively determining a blood flow velocity change following the lipid solution injection; and

(vi) distinguishing between different types of the animal microvasculature based on the blood flow velocity, the blood flow direction, and the blood flow velocity change.

14. The method of claim 13 , wherein the lipid solution includes at least one of a fat emulsion, a total parenteral nutrition solution, a parental nutrition solution, or a total peripheral nutrition solution.

15. The method claim 13 , wherein the Doppler shift is a continuous Doppler shift.

16. The method of claim 13 , further comprising:

determining a backscattering of a light produced by the lipid solution based on the imaging scans; and

calculating the blood flow velocity and the blood flow direction in capillaries based on the Doppler shift and the backscattering of the light.

17. An Optical Doppler Tomography (ODT) method for distinguishing between different types of animal vasculature comprising:

(i) injecting a lipid solution into a bloodstream of an animal so that the blood stream carries the lipid solution to a specific site;

(ii) applying a laser beam to the specific site so as to generate a Doppler frequency shift of the laser caused by the lipid solution flowing through capillaries at the specific site;

(iii) generating a three-dimensional tomographic image of the capillaries at the specific site on the basis of the Doppler frequency shift of the laser;

(iv) calculating a blood flow velocity and a blood flow direction in the capillaries at the specific site on the basis of the Doppler frequency shift of the laser; and

(v) distinguishing between different types of the animal microvasculature based on the blood flow velocity and the blood flow direction.

18. The method of claim 17 , wherein the lipid solution includes at least one of a fat emulsion, a total parenteral nutrition solution, a parental nutrition solution, or a total peripheral nutrition solution.

19. The method of claim 17 , further comprising imaging the capillaries or the blood flow in the capillaries three or more times following the injection of the lipid solution.

20. The method of claim 19 , wherein the imaging the capillaries or the blood flow in the capillaries is performed about 1 hour following the injection of the lipid solution.

21. The method of claim 19 , wherein the imaging the capillaries or the blood flow in the capillaries is performed about 3 hours following the injection of the lipid solution.

22. The method of claim 19 , wherein the imaging the capillaries or the blood flow in the capillaries is performed about 6 hours following the injection of the lipid solution.

23. The method claim 17 , wherein the Doppler shift is a continuous Doppler shift.

24. The method of claim 17 , further comprising:

determining a backscattering of a light produced by the lipid solution based on the three-dimensional tomographic image; and

calculating the blood flow velocity and the blood flow direction in the capillaries based on the Doppler frequency shift and the backscattering of the light.

25. A method of distinguishing between different types of animal microvasculature in an animal, comprising:

(i) injecting a lipid solution into a bloodstream of the animal;

(ii) imaging microvasculature of the animal using an Optical Doppler Tomography (ODT) system having an axial resolution of about 1.8 μm and a transverse resolution of about 3 μm;

(iii) calculating a blood flow velocity and a blood flow direction in the microvasculature; and

(iv) distinguishing between different types of the animal microvasculature based on the blood flow velocity and the blood flow direction.