First Image Taken With an Ultra Low Field MRI

KentuckyFC writes "MRI machines are about to get smaller, much smaller. Most of their bulk is taken up by the huge superconducting magnets required to generate fields of a few Teslas. Now a team at the Los Alamos National Lab in New Mexico has built a machine that can produce images using a field of only a few microTesla (PDF, abstract here). So giant superconducting magnets aren't necessary, a development that has the potential to make MRI machines much smaller, perhaps even suitcase-sized. The one-page paper shows sections of the first 3D brain image taken with the device."

Comments

Hidden monkeys

[LiquidCoooled]

I thought the images were of monkeys at first, however when I went to have a look at MRI images of a human head was thankfully proven wrong (some of us have our monkey origins hidden better than others).

So, for comparison here is a page with images of human heads in a normal MRI.
(single image here)

I hope they get the focusing better (which is what I understand the power is used for) because this will be a good progression.

Article's title is misleading

[IvyKing]

This may be the first image of a human head with an ultra low field MRI, but ULF MRI images have been made for at least a decade and a half. Magritek, a New Zealand company, makes a low cost unit ULF MRI system, though the image volume is limited to about one liter.

Another company, Vista Clara, is using a novel form of ULF MRI to map groundwater.

Re:Article's title is misleading

[ceoyoyo]

The summary is VERY incorrect.

This isn't an ultra low field MRI, it's a DUAL field MRI. In a normal scanner you have a big, static magnetic field that polarizes the sample and remains for readout. In one of these dual field scanners you use the big field (or a bigger field, it's usually a resistive electromagnet so it can't be anywhere near as strong as a superconductor) to polarize the sample then you shut it off and use a much smaller field for readout. There are a few advantages, the one the abstract focuses on is that you can do things like MEG in a very low field. The other is that energy deposition is related to the field strength so by using a small field you can use imaging sequences that would otherwise pump too much energy into the subject.

One of the guys working on this technology visited my lab last year. It was a very interesting presentation.

I believe someone has produced an MR image using the Earth's magnetic field. They've certainly done nMR in the Earth's field. You can't get much lower than that on this planet.

Re:Article's title is misleading

[Anonymous Coward]

Earth's field and low field MRI are actually relatively common. There has even been NMR work done at ~1uT in a shielded chamber.

Re:Stronger pre-polarizatin field is used

[IvyKing]

The Larmour frequency for 30 mT is about 1.28 MHz, which is in the AM broadcast band. Interference is likely to be a significant problem.

Re:Nothing _that_ new...

[ceoyoyo]

Not quite. Higher gradients give you faster imaging. Higher fields give you better signal to noise. Better signal to noise can allow you to actually use those higher gradients without ending up with a big mess of noisy pixels.

If you've got lots of time you can achieve more or less any resolution you want with any field strength you like. The problem is, the darn patients keep getting impatient and moving.

The summary is pretty wildly inaccurate. This is actually a dual field scanner that uses a stronger field to polarize the sample and a weaker one for readout. It's pretty cool, but it's a niche thing... these guys want to do MEG scanning along with MRI and MEG is allergic to large magnetic fields. It won't be replacing the regular superconducting scanners and it won't be making cheap in-home scanners possible.

You can do nMR in the Earth's magnetic field if you want to. It's actually possible to set it up at home. I think someone was selling science kits for a while.