Two new technologies to enhance magnetic resonance imaging (MRI) could help make the experience of scanning less stressful and provide sharper images. Both techniques — one from Siemens, the other from the Fraunhofer Institute for Computer Graphics — reduce the need for the MRI subject to remain completely still during the scan.
The Siemens technology is a piece of software called syngo Blade, and works by using the MRI machine to take rapid low-resolution images at regular intervals throughout the scan. The imager’s processing system combines the low-resolution images, calculating how the patient moved during the scan, then uses this data to construct a high-resolution image as if the patient had kept still.
Siemens believes the syngo Blade technology is particularly useful for conducting MRI scans on children, who find it very hard to keep still. Currently, one in three children under ten years-old have to be sedated during MRI scans. It will also make it easier to produce scans of people who have neurological conditions which make them tremble uncontrollably, and to produce images of the lungs — currently, patients have to hold their breath to produce a clear MRI of the respiratory system.
The Fraunhofer system, meanwhile, is designed specifically for head MRIs, and is based around technology similar to that used to produce computer-generated characters in films. Called Promo, the system uses image capture to follow the position of the head during the scan and adjusts the image accordingly.
The patient’s head rests inside a headpiece which includes a T-shaped bar carrying three reflective position markers. Before the scan, the patient bites down on the bar for a few seconds; it is then held in place by a slight vacuum. The Promo system then records the position of the markers and, as with the Siemens system, recalculates the image.
The Fraunhofer team, led by Christian Dold, claims that the system is so effective that it can be used for functional MRI (fMRI), a refined scanning system which can detect and follow the chemical changes in brain tissue that indicate neural activity. The fMRI technique is so sensitive that even movement of 1mm could render the images useless.
The Fraunhofer method: patients bite on a Y-shaped bar with position markers