Removing brains
Posted: Tue Sep 19, 2023 8:12 pm
I've now removed a fair number of brains, so I'm developing some opinions about the procedure. Many of them were research cases rather than patients, and the quality was admittedly not ideal. So after I had removed the first few, I decided firmly that I would not want that done to my brain because of all the physical trauma it caused. But the quality is gradually getting better. The technique is improving. The tools are getting better. I did a cat brain today with zero obvious physical trauma. So if the technique gets perfected, I might not be so opposed to it.
Why would we want to remove a brain? Well, it seems like we absolutely must if perfusion was not successful. If the fixative and/or cryoprotectant did not reach 100 percent of the brain tissue, then we must remove the brain in order to soak it in fixative and/or cryoprotectant. Cooling without adequate cryoprotection causes too much damage. We are able to validate whether perfusion was successful prior to removing the brain. We do this with a CT scanner which provides us quantitative proof of adequate perfusion. In fixative cases, we can use a radiopaque agent, and in cryoprotectant cases, the DMSO easily shows on the CT scan.
If perfusion was 100% successful, then removing the brain is not required, but I suspect that will not be the norm. As we start to do dozens or hundreds of these cases, we will have statistics on what percentage were not perfused successfully. We can't get this info from Alcor or CI because they don't do CT scans after perfusion. So a truly ideal case with very good perfusion might allow preservation of the entire cephalon, but I think most cases will require removal of the brain in order to complete the chemical treatment. This means it's absolutely essential to get better at removing brains atraumatically. I'm convinced this is possible, but will require a lot of work.
Why would we want to remove a brain? Well, it seems like we absolutely must if perfusion was not successful. If the fixative and/or cryoprotectant did not reach 100 percent of the brain tissue, then we must remove the brain in order to soak it in fixative and/or cryoprotectant. Cooling without adequate cryoprotection causes too much damage. We are able to validate whether perfusion was successful prior to removing the brain. We do this with a CT scanner which provides us quantitative proof of adequate perfusion. In fixative cases, we can use a radiopaque agent, and in cryoprotectant cases, the DMSO easily shows on the CT scan.
If perfusion was 100% successful, then removing the brain is not required, but I suspect that will not be the norm. As we start to do dozens or hundreds of these cases, we will have statistics on what percentage were not perfused successfully. We can't get this info from Alcor or CI because they don't do CT scans after perfusion. So a truly ideal case with very good perfusion might allow preservation of the entire cephalon, but I think most cases will require removal of the brain in order to complete the chemical treatment. This means it's absolutely essential to get better at removing brains atraumatically. I'm convinced this is possible, but will require a lot of work.