Magnetic resonance imaging (MRI) requires very expensive scanners, and special facilities to host them. As things stand, most hospitals around the world can’t afford an MRI machine. Things may soon get a bit easier thanks to new metamaterials, developed at Boston University, that improve the quality of MRI imaging. This development may allow lower power MRI scanners, which also cost less, to deliver imaging quality that is comparable with that of more powerful devices.
The most obvious way to improve MRI image quality is to use ever more powerful magnets, but this is also the most expensive route. The Boston University team instead focused on improving the fidelity of the radio waves that are emitted by the body into the MRI machine. They have created a metamaterial device, which should cost about $10 to manufacture, that can be positioned next to the body part being imaged to automatically improve MRI image quality.
MRIs transmit relatively high energy radio signals into the body, triggering lower energy bursts to bounce back. The new metamaterial device, made of copper wires and plastic, is made to increase the power of the returning signal, which shows up in clearer images.
One other improvement the team made to the device is that it turns its functionality off when the scanner is transmitting its radio signal and turns on immediately after, only boosting the power of the return signal. This leads to an even greater improvement in image quality.
“The intelligent metamaterial consists of an array of metallic helical resonators closely packed with [a passive sensor],” said Xiaoguang Zhao, one of the researchers. “When the high-energy radio waves are coming in, the metamaterial detects the high energy level and ‘turns off’ the resonance automatically. With low-energy radio excitation, the metamaterial [turns on] the resonance and enhances the magnetic component of the radio wave.”
The team believes that not only will the technology make MRI scanners more accessible worldwide, but that it will also allow scans to be performed faster, and for high end devices to image with unprecedented fidelity.
Here’s a Boston University video describing the workings of the new metamaterial:
Study in journal Advanced Materials: Intelligent Metamaterials Based on Nonlinearity for Magnetic Resonance Imaging
Related study in Nature Communications Physics: Boosting magnetic resonance imaging signal-to-noise ratio using magnetic metamaterials
Via: Boston University