High Contrast

Allowing doctors to see inside their patients, MRI (magnetic resonance imaging) scans are especially critical for diagnosing problems in the brain, from aneurysms to tumours. MRI creates images by harnessing the body’s magnetic properties. During a scan, powerful magnets realign subatomic particles, known as protons, in the body’s water molecules, then pulses of radio waves briefly perturb their alignment. When the protons return to their resting state, they emit radio waves of their own, and as different tissues vary in their response, measuring these signals allows us to build detailed images of internal structures. Modulating the characteristics of the pulses helps refine results, and researchers recently devised new techniques for improved detection of brain cancers. By selectively enhancing or dampening signals from surrounding blood vessels, they obtain clearer images, where small tumours stand out more (left panel, compared to a more traditional technique on the right), hopefully enabling earlier diagnoses.

Written by Emmanuelle Briolat

Emmanuelle Briolat

Writer

A researcher specialising in visual signals in Lepidoptera, camouflage and the effects of light pollution, Emmanuelle’s writing covers a range of topics, from biomedical research to children’s books about moth defences.

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• Image from work by R. Edelman and colleagues
• Radiology, NorthShore University HealthSystem, Evanston, IL, USA
• Image originally published with a Creative Commons Attribution 4.0 International (CC BY 4.0)
• Published in Science Advances, October 2020