This method is a reliable and easy technique for visualizing real-time blood flow in aneurysms and vessels and can be used in different animal models. The main advantage of this technique is that it facilitates visualization of blood flow during surgery without requiring any expensive devices or extensive surgery. Before beginning the procedure use black tape to secure a green bandpass filter to act as an excitation filter onto a flashlight.
And check that the flashlight only emits blue light. Equip the camera with a green bandpass filter to function as an emission light filter. Only green light should now be able to pass through.
Then, disinfect the work space with a disinfectant solution and cover the table with sterile drapes to prevent contamination. To perform fluorescein video angiography or FVA in a rabbit confirm that the anesthetized animal does not respond to pain stimulus before positioning the rabbit in the supine position. Shave the neck around the sternocleidomastoic muscle.
Focus the camera on the dissected artery and use aluminum foil to cover a five milliliter syringe containing 100 milligrams/milliliter of fluorescein sodium. Turn off the lights as much as possible and inject 0.3 milliliters/kilogram of fluorescein sodium intravenously into the injection port of the catheter. Next, flush the syringe with 0.5 milliliters of saline solution to ensure that all of the dye has been injected.
And immediately illuminate the surgical field with the modified flashlight. As soon as the light is turned on begin filming with the modified camera. Blood flow should be visible within a few seconds of the injection.
For macroscopic analysis of the vessel after angiography resect the aneurysms and the parent artery complex in follow-up animals, or perform visual confirmation of flow by observing the filling of the aneurysm and/or bypass after removal of the temporary clips. In this representative study, FVA was able to be performed in eight out of 10 rabbits. Of the 16 aneurysms identified in the eight rabbits two aneurysms demonstrated persistent perfusion of the parent artery, while FVA identified five cases with residual perfusion.
14 rabbit aneurysms exhibited no residual perfusion macroscopically, while 11 were subsequently detected using FVA. Residual perfusion was observed macroscopically in 23 of 48 rats, and the other 25 rats showed no macroscopic signs of residual perfusion. 22 of the 23 aneurysms without macroscopic perfusion were then confirmed using FVA.
Overall, 25 of 27 rabbit and rat combined cases could be confirmed, resulting in a positive predictive value of 92.6%a sensitivity rate of 100%and a specificity of 94.1%The most important things when attempting this procedure are to dissect the vessels properly and to work in a darkened room when administering and visualizing fluorescein. This procedure can be used in any animal model to evaluate blood flow in any visible vessel.
