New test for heart disease

A new imaging technique using an MRI device can detect heart disease, and so could spare many heart patients an invasive, expensive and uncomfortable test. Three dimensional coronary magnetic resonance angiography is an accurate non-invasive method for identifying diseases of the coronary arteries. MRI is magnetic resonance imaging, a special test that produces very clear and detailed pictures of the organs and structures of the body. It uses a powerful magnetic field, radio waves, and a computer to create three dimensional images. Patients have to lie inside the MRI machine which has a giant electromagnet In an angiogram, a catheter is threaded from a groin or arm artery up to the main artery of the heart. The catheter then injects a dye that can be seen on a "movie" X-ray, helping doctors spot blockages. Angiograms produce very clear pictures but cause complications in few patients getting the test, including a slight chance of artery damage or a heart attack. So researchers have been seeking a way to get similar results without the risks or other drawbacks. This new technique (three dimensional coronary magnetic resonance angiography) was developed at the Beth Israel Deaconess Medical Centre, Boston. Researchers have adapted the technology to produce a series of high-resolution images of the relatively small coronary arteries. They performed coronary magnetic resonance angiography in 109 men and women before they had elective X-ray coronary angiography, and compared the results. Overall, coronary magnetic resonance angiography had an accuracy of 72% in diagnosing coronary artery disease. For patients with left main coronary artery disease the sensitivity of this method was 100%, specificity was 85% and accuracy was 87%. Conventional coronary angiography still remains the standard owing to its high image quality. However, it is an invasive technique with life threatening complications such as heart attack, stroke, and sudden death. It also takes longer, requires a brief stay in the hospital for observation and is much more expensive than magnetic resonance angiography. The major advantage of magnetic resonance angiography is that radiation is not used. However, magnetic resonance angiography may produce inadequate images and the patient must repeatedly hold his breath. Its use is also restricted in patients with metal implants or claustrophobia. However this technique is an important advancement, and in few years, it is expected to overtake the conventional angiogram. Advances will bring sharper images, allowing doctors to spot even tiny lesions that may lead to heart attacks.