MRI-Compatible Video & Sound Systems

Clinicians and research scientists use magnetic resonance imaging (MRI) to visualize both the structure and function of different parts of the body, such as the brain. This technique relies on the use of powerful static magnetic fields, with field strengths comparable to those of the magnetic cranes used to lift automobiles. Since MRI uses such powerful magnetic fields, all electronics used near these machines must be specifically designed to be "MRI compatible," or in other words to safely and reliably function in strong magnetic fields. A number of companies have designed MRI-compatible video and sound systems that function near MRIs and serve a number of uses.

MRC MRI-Compatible Video Cameras

• Specifically designed video systems allow clinicians and researchers to observe patients or study subjects undergoing an MRI. These systems are typically mounted in the bore of the MRI, but can also be mounted on imaging coils or elsewhere in the scanner. They provide a real-time video feed to the control room for observation. MRC manufactures a number of MRI compatible video systems. These systems collect video using white or infrared light, mount in various ways and come with a standard or longer-range lens.

MSI Relaxation System

• An MRI bore is a loud confined space. Accordingly, many people experience some discomfort or anxiety when undergoing an MRI, which can be particularly pronounced in people with claustrophobia. MRI-compatible video and sound systems can increase comfort by allowing people to watch video recordings and listen to audio playbacks during an MRI. According to MSI, their "relaxation system" increases the comfort of patients or study subjects by allowing them to watch a movie, watch TV or listen to music during the scan. Furthermore, they claim that their system results in no degradation of the quality of the images and further augments patient comfort by damping the loud noises produced by the MRI.

MRA Stimulus Delivery System

• An MRI can be used to image structures in the body but can also be used to study function, in particular the function of various parts of the brain. This type of MRI is called a functional MRI (fMRI). In many cases, the video and sound equipment used during an fMRI scan present stimuli that change brain functions. These fMRI scans rely on rapid changes in the static magnetic fields, which can generate forces and currents in electronic equipment. The Magnetic Resonance and Image Analysis Research Center has described a number of challenges inherent to use of video and audio equipment during fMRI scans. Importantly, the increased demands of this technique require equipment that must be even more refined than equipment used during a structural MRI, including the use of special wiring, RF filters or fiber optics. MRA manufactures an fMRI-compatible stimulus delivery system. The system comes with a patient response pad, fiber optic presentation equipment and stereo sound equipment and can be remotely controlled from the operator room.

Applied Science Laboratories Eye Tracking Systems

• In some research studies and clinical diagnostics, it is helpful to determine where on a screen a patient is looking. For example, autistic patients may spend less time looking at the faces of people in movies than control subjects. MRI-compatible video equipment allows researchers and clinicians to determine where a subject or patient is looking on a video presentation screen by determining the gaze path of the person's eye to the screen. These systems use reflected light projections and rapid video recording. Applied Science Laboratories (ASL) manufactures a variety of eye tracking systems that use long-range optics and have been installed in over 70 locations worldwide. ASL also sells software for calibrating, recording and analyzing the data from these systems.