T1 Mapping Could Provide for Safer Heart Scans

Developed by researchers at Oxford University (United Kingdom), the new technique makes use of a property of hydrogen atoms to create a pixel-by-pixel map called a shortened modified look-locker inversion (ShMOLLI) T1-map, which allows examination of healthy and diseased heart tissue in greater detail than before. According to the researchers, T1 mapping could improve heart scans for patients, giving more information about the heart than traditional scans and all without any injections, making them safer and faster.

T1 maps provide an objective number that indicates the length of time atoms take to return to a normal thermodynamic state after being affected by radio waves and strong magnetic fields. During cardiac scanning, the T1-map helps to visualize areas of the heart suffering from lack of blood supply due to blocked arteries, since long T1 times indicate the presence of more water, something found in a number of heart conditions. It takes around three minutes to map the whole heart, and the values it measures are turned into a color-coded map, giving doctors an image which is potentially quicker to understand and with less subjective interpretation.

“T1 mapping allows us to look in finer detail at the heart in a noninvasive way, which has not been possible before. We can now get results without Gadolinium, meaning we have a technique that is safer and quicker and can be used with more people,” said study coauthor Stefan Piechnik, PhD, MScEE, who developed the specific ShMOLLI T1 mapping technique used at Oxford. “The results are also less dependent on interpreting the images—medics have something based on hard numbers.”

“The potential of this research is huge—not only for heart scans. Each type of tissue across the body has a range of normal T1 values, so any values outside that range may signify disease; the pixel by pixel level of detail from these scans could help identify unhealthy tissue wherever it appears,” said senior author Vanessa Ferreira, MD, PhD, deputy clinical director of the Oxford Centre for Clinical Magnetic Resonance Research (OCMR). “Oxford is now applying this technique to scan other organs.”

Current stress scans of the heart using magnetic resonance imaging (MRI) that requires patients to be injected with two substances. The first is adenosine, which is injected to cause effects similar to exercise during the scan. Gadolinium—a rare earth heavy metal—is then injected as a contrast agent to highlight areas of the heart suffering from decreased blood flow under exercise conditions.

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