First Ever Real-Time MRI Video Captures Images of Body's Interior in Just 20 Milliseconds

A Real-Time MRI Image of a Heart

Frahm / MPI for Biophysical Chemistry

Those long periods of lying completely still inside that intimidating MRI tube may soon be a thing of the past. Employing some tricky math and some heavy-duty computing power, researchers at the Max Planck Institute in Göttingen have developed a new MRI method that renders images in just one-fiftieth of a second, fast enough to capture organs and joints "live" for the first time.

Magnetic resonance imaging (MRI) used to take several minutes to capture a single image, requiring patients to remain perfectly still in order to get a clear cross-sectional image of an internal organ or joint for use in diagnosis. This meant that while MRI was far preferable to X-ray -- which requires the patient to be doused with radioactive waves -- the technique was highly sensitive to any movement by the patient and could not actually capture an internal process in video-like motion.

New techniques such as FLASH (fast low angle shot) have greatly increased the pace at which an MRI machine can capture an image, but none has come close to being able to capture real-time processes like the beating heart or joint movement inside the body live. But this newest technique does exactly that by reducing the amount of time the machine needs to capture individual frames to just 20 milliseconds.

To enable such a leap in image rendering times, the team had to engineer algorithms that allow a computer to assemble a complete image from a less-than-perfect set of image data. Coupled with radial encoding of the spatial information, which makes the images insensitive to movements, some clever mathematics allows the MRI machine to fill in gaps in the image data such that a complete frame can be pieced together from as little as five percent of the data normally needed to create an image.

The new MRI method can be easily adapted to modern imaging equipment, but the process is hindered by computing power; a real-time MRI rendering of a beating heart for one minute will produce 2,000-3,000 images that must each be rendered and stitched together into a seamless video, eating up 2 gigabytes of memory. The whole process would take the program about 30 minutes to complete, so researchers still haven't reached the point of real-time, live MRI video, but they're getting there.

In the meantime, half an hour isn't so long to wait for a moving MRI video that should help researchers more accurately diagnose everything from joint injuries to coronary heart disease.