The findings, by investigators from the University of Leeds (UK), could change the way that individuals with suspected heart disease are assessed, potentially avoiding the need for tests that are invasive or use ionizing radiation. Results of the study, which was funded by a GBP 1.3 million grant from the British Heart Foundation (BHF; London, UK), were published online December 2011 in the medical journal the Lancet.

Coronary heart disease (CHD) is a leading cause of death and disability worldwide. In the United States, an estimated 18 million men and women are living with the disorder, resulting in an estimated cost to the economy of USD 177.1 billion in 2010.

CHD is caused when vital arteries serving the heart become narrowed or blocked by a build-up of fatty substances. This can lead to severe chest pain, known as angina, and if the condition worsens and remains untreated, patients may have a heart attack.
Patients with chest pain who are suspected of having angina will typically be sent to the physician for additional testing. These tests will validate the diagnosis of CHD and help clinicians choose the best course of treatment option, which may involve drug therapy, a balloon “stretch and stent” procedure to open-up narrowing in the heart’s blood vessels--or a heart bypass procedure.

Currently, patients with suspected angina are most likely to have either an angiogram--an invasive test where dye is injected directly into the heart’s arteries--or a noninvasive imaging test called single photon emission computed tomography (SPECT). Similar to MRI scans, angiograms and SPECT both involve ionizing radiation.

A five-year study by University of Leeds researchers, involving 752 patients, has now shown that an MRI scan is a reliable way of detecting signs of significant CHD. The researchers also showed that MRI was better than SPECT at diagnosing CHD and at ruling out heart disease in patients who did not have the condition.

This is the first time that MRI has been compared head-to-head against the gold standard tests for CHD in such a large group of patients. The findings may now lead healthcare policy-makers to re-evaluate supervision on the imaging exams that patients with suspected CHD should be offered.

University of Leeds’ Dr. John Greenwood, who led the study, said, “We have shown convincingly that of the options available to doctors in diagnosing coronary heart disease, MRI is better than the more commonly-used SPECT imaging test. As well as being more accurate, it has the advantage of not using any ionizing radiation, sparing patients and health professionals from unnecessary exposure. The MRI technique could be used widely and not just in the UK. The scans were all carried out on a standard 1.5 Tesla scanner--exactly the type of MRI scanner that you would find in most hospitals today.”

Prof. Peter Weissberg, medical director at the British Heart Foundation, said, “For patients suffering with chest pains, there are a number of tests that can be used to decide whether their symptoms are due to coronary heart disease or not. This research shows that a full MRI scan is better than the most commonly used alternative--a SPECT scan using a radioactive tracer. “MRI has the additional advantage that it doesn’t involve radiation. At present, not all hospitals have the expertise to undertake such scans but these findings provide clear evidence that MRI should be more widely used in the future.”

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