We spend a lot of time at UCSF’s Advanced Imaging Facility in Mission Bay, these days. Every 6 weeks or so, we ‘volunteer’ to be a guinea pig for new software and other imaging advances: in return our neuro-oncology team gets state-of-the-art images of my brain, which images help keep me and the neuro-onco team on top of the current state of my condition.
Last time I was there, I got a peek at the newly-installed 7-Tesla machine, and was told I could volunteer to be scanned if I wished. After 30-plus MRIs, former extreme-claustrophobe I signed right up. Tomorrow is the big day.
MRI machines work by bathing the body in extreme magnetic fields, which cause the protons in the water molecules of tissue to generate a faint signal that can be turned into image data by a very sophisticated combination of hardware and software. The standard MRI machine in most US hospitals has a field strength of 1.5 Tesla, a magnetic field equivalent to 30,000 times Earth’s magnetic field.
The ‘standard’ machine at Advanced Imaging produces 3 Tesla – the higher field strength produces either higher resolution or the same resolution in a shorter time vs. a 1.5 Tesla machine. The 1.5- and 3-Tesla machines, made by General Electric are very large cylinders with a central bore big enough to fit a human head to toe. Appliance maker G.E. has productized these machines nicely with a dapper ivory and gray plastic housing, complete with the century-old G.E. logo tastefully embossed on the front.
By contrast, the 7-T machine (which weighs 66,000 pounds – more than 30 tons) looks like something from a Soviet military lab – a very big cylinder (‘aircraft’ or ‘submarine’ come to mind) with huge supports and very large plumbing and other hardware jutting curiously out of the giant, central mass. The whole thing is cooled to minus 459 degrees (aka ‘absolute zero’) by a combination of liquid nitrogen and liquid helium in what is, essentially, a gigantic refrigerator (something else GE makes).
The tube is deep, deeper than the 3-T machines, and I’ve been warned I have to wear a mask over my eyes. The bore, however, is wider – more shoulder room think I, and given that brain MRIs require my head be tightly strapped into a cage about the dimensions of a football helmet, I don’t think the 7-T is going to be that much more difficult to endure – it’s not like you have much of a view in a MRI machine, anyway.
My last MRI left some questions about what, exactly, has been going on inside my brain. While the 7-T machine is technically not approved for medical diagnosis, and I have to also undergo a ‘back-to-back’ 3-T scan so the diagnosis can be ‘legal,’ I, and my neuoro-oncologist, look forward to the 7-T images. We’ll publish same here, if I can get copies…