Prototype of new brain scanning technology

Technology Review has an article on a prototype MRI scanner that could vastly improve our ability to measure brain function. It uses a lattice of small coils positioned around the head rather than large coils you lie inside.

MRI uses very strong magnets that align the spin of the atoms in your body. It then sends a radio pulse which knocks the atoms out of alignment.

After the knock, the atoms return to their previous alignment but the time taken will differ, depending on the body tissue. As they return, they send off their own pulse, this is picked up by the coils, and these are computed into a ‘map’ of the tissue.

The coil is essentially tube shaped. It might be big enough for your entire body, or just big enough for your head to fit inside, as this image shows.

The new protype scanner, developed by Siemens, instead has an overlapping series of small circular coils positioned around the head, as you can see in the picture.

The idea is that they will be more sensitive and only focus on a small area of brain, and the information from each will be combined into a complete data set.

One major hope is that the scans will have even more detail than conventional MRI, which divides the brain up into chunks that are approximately 3mm across in all direction.

Although this is quite small, it’s still too big to pick up the brain’s fine detail.

The device is likely to have important applications in functional magnetic resonance imaging (fMRI), a variation of standard MRI that tracks blood flow in the brain as an indirect measure of activity. The technique is often used to locate the parts of the brain that control specific functions, such as speech and movement. The first clinical application for the device will likely be fMRI for neurosurgery planning, says [Siemens MR vice president] Bundy. “Surgeons want to know where speech and motor areas are when they take a tumor out–the more precise, the better.”

The instrument could also impact our basic understanding of the brain. “The spatial resolution of fMRI is somewhat limited,” says Gabrieli. “We’ve hit the wall on a lot of scientific questions.” With higher-resolution images, scientists could try to determine neurological basis of various aspects of cognitive function. Gabrieli, for example, says that he’d like to figure out if different parts of the amygdala–a small structure deep in the brain that plays a key role in emotion–regulate different emotions, such as fear and joy.

One restrictive aspect of current fMRI is that the person has to be lying down and is inside a tube. This make many types of experiments (e.g. on limb movement) virtually impossible to conduct.

If, like other brain scanning technologies PET and MEG, the person could be sitting up, it would mean a far more diverse range of studies could be done in fMRI.

Sometimes the most important effects are the simplest, even if they need to be enabled by advances in high-technology.

Link to TechReview article ‘A Better Brain Scanner’.

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