No need MRI ; No need CT ; The new Seismic Brain imaging

Yeah. You read it correct. For years, scientists have been trying to find an alternative to CT and MRI to image brain. But why? Aren’t they the most superior imaging technologies?And what is the newer alternative that can replace MRI and CT? Read this article.

Difficulties with MRI

Magnetic Resonance Imaging (MRI) is generally the best method for obtaining high-resolution images of the brain, and its use is currently essential to the investigation of many neurological disorders including stroke, brain cancer, and brain injury. Then why need an alternative technology? Because, MRI requires large, complex, expensive, non-portable machines cooled to three degrees above absolute zero, and it cannot be used on patients for whom the presence of metallic implants or foreign bodies cannot be ruled out. This makes emergency use in patients with potentially altered consciousness, such as those suspected of stroke, difficult or impossible.

Seismic brain imaging

Scientists have developed a new computational technique that could lead to fast, finely detailed brain imaging with a compact device that uses only sound waves.

The Imperial College London and UCL researchers say their proof-of-concept study, published in npj Digital Medicine, paves the way for the development of high-fidelity clinical imaging of the human brain that could be superior to existing technology.

Unlike existing brain imaging methods like MRI, CT and PET scanning, the technology could be applied to imaging any patient, and could be suitable for the continuous monitoring of high-dependency patients. It could be delivered by a relatively small device, which would also potentially make it portable via ambulance and enable fast investigation in advance of arrival to hospital.

The researchers are confident the technology will be safe as sound waves are already used for ultrasound scanning and this technology uses similar sound intensities. Ultrasound cannot easily penetrate through bone, whereas the new device, which is designed to be worn like a helmet, is able to overcome this barrier. The new approach is of special value in patients investigated for stroke – the second commonest cause of death and commonest cause of adult neurological disability – where rapid, universally applicable, high-fidelity imaging is essential.

“An imaging technique that has already revolutionised one field – seismic imaging – now has the potential to revolutionise another – brain imaging.”

 Dr Lluís Guasch, of Imperial’s Department of Earth Science and Engineering

Transcending Technology

Earth scientists use seismic data and a computational technique called full waveform inversion (FWI) to map the inside of the earth. Seismic data from earthquake detectors (seismometers) are plugged into FWI algorithms that extract 3D images of the Earth’s crust that can be used to predict earthquakes and search for reservoirs of oil and gas.

Now Imperial researchers have adapted this approach to medical imaging, developing a method that uses sound waves with the ultimate aim of producing high-resolution images of the brain.

They built a helmet lined with an array of acoustic transducers that each sends sound waves through the skull. The ultrasound energy that propagates through the head is recorded and fed via the helmet into a computer. FWI is then used to analyse the reverberations of the sound throughout the skull, constructing a 3D image of the interior.

The researchers tested their helmet on a healthy volunteer and found that the quality of the recorded signals was sufficient for the algorithm to generate a detailed image, and they are confident the scattered energy from the brain will be interpretable.

Using computer modelling, they also found they could obtain high-resolution images with sound frequencies low enough to penetrate the skull at safe intensities.

“The practicalities of MRI will always limit its applicability, especially in the acute setting, where timely intervention has the greatest impact. Neurology has been waiting for a new, universally applicable imaging modality for decades: full-waveform inversion could well be the answer.“