Cardiac MRI is one of the most powerful assessment tools for the heart. MRI technology has dramatically improved over the last few decades, with routine assessment of heart volumes, function and blood flow though non-invasive MRI scanners without the use of harmful radiation. A major leap forward in this technology will allow the assessment of complex heart disease using 4D techniques.
This remarkable new imaging technology not only shows blood flow, direction, and velocity in 3D, but can also show them relating to a fourth dimension – time. The procedure is fast, requires no invasive procedures, no contrast agent or general anesthesia and could have significant consequences for patients at risk of cardiac problems.
Until now cardiologists have measured blood velocity with MRIs that require a patient to be completely still for up to 60 minutes in order to capture the 20 to 30 slices needed to scan the entire heart. Ultrasound is also sometimes used but other anatomy can make it difficult to see some areas of the heart. Furthermore the images from both are typically 2D, though sometimes 3D.
With the new technology the MRI scan takes only ten minutes, and while wriggly children might need to be sedated, patients don’t need to be absolutely still for long periods. From a short procedure technicians can produce remarkable images to measure how fast blood is flowing through the heart and the major arteries around it. Blood flowing through the heart is seen as a bundle of long filaments colour-coded to indicate the speed of the flow at various locations in the heart. For instance, blue threads represent relatively slow flow, whilst red and yellow threads show abnormally fast blood flow in patients who many have heart problems.
In addition to this, direction of blood is depicted and the effects of any obstructions or deviations on blood flow can be determined. We hope the the new technology could be adapted to analyse blood vessel walls as well by identifying weak areas or areas under increased stress that could lead to aneurysms or build-up of damaging plaque. This would have far-reaching effects for any patients with heart defects or at risk of cardiac problems.