An advance in magnetic resonance imaging (MRI) developed by researchers at Northwestern University Medical School and Siemens Medical Systems may radically improve the ability to determine which patients with coronary artery disease will benefit from bypass surgery or angioplasty.
The investigators, led by Northwestern cardiologist Raymond J. Kim, M.D., and basic scientist Robert M. Judd, used an improved version of contrast-enhanced MRI in 50 patients with heart disease who were scheduled to have bypass surgery or coronary angioplasty.
The scientists found that contrast-enhanced MRI considerably boosted image intensity over previous methods and enabled the researchers to distinguish between reversible and irreversible heart injury.
Drs. Kim and Judd explained that with this technique, heart regions damaged by heart attack or other coronary artery disease appear on MRI as hyper-enhanced, or ‘bright.’
The researchers found those areas of the heart that were ‘dark’ on the MRI recovered following bypass surgery or angioplasty, whereas ‘bright’ areas did not recover after surgery.
The research group also reported that contrast-enhanced MRI is the first technique to allow physicians to view the extent of damage within the heart wall following a heart attack.
The ability to look at damage within the wall of the heart is made possible because of the high spatial resolution of MRI and the capability of the new technique to contrast dead and living areas of the heart.
‘We found that when most of the thickness of the heart wall was ‘bright,’ there was only a 2 percent chance of improvement following bypass surgery or angioplasty,’ said Judd.
‘This indicates that MRI performed before surgery can identify patients who are unlikely to benefit from the intervention and an unnecessary procedure can be avoided,’ added Judd.