Alessandro Sbrizzi

A photographer snaps a runner: to avoid a blurry shot, a short shutter speed is needed. An MRI scanner is like that photographer, but its 'shutter speed' is long — by the time it captures, the muscle has already changed. That's why dynamic MRI (a series of volumetric frames in motion) is a tough challenge: data are scarce, and motion doesn't wait.

The heart beats irregularly. Standard MRI pretends all beats are the same: it stacks them on top of each other, like a photographer shooting a dancer with a long exposure. The result is a blurry smudge — pretty, but useless if you need to see each individual movement. The new approach films the heart like a video: frame by frame, with no gaps.

A sculptor looks at a block of marble and sees the figure within, waiting to be freed from excess material. Instead of adding clay, he removes everything that is not part of the form. The authors of a new study on magnetic resonance took a similar approach: rather than complicating the tissue model by adding ever more details, they stripped away the superfluous to reveal the essence.