We have investigated a new method for diagnosing diseases of the artery using Magnetic Resonance Imaging. This method is based on the rate of exchange between water and protein protons in the tissue. The goal was to develop a method that is not based only upon water signal, but protein, in order to characterize changes in blood vessel wall.
The method proved to be indeed a new method for contrast between tissues. We have implemented the method on arteries of sheep and pigs. We also tested the method on porcine liver, and on porcine muscle in order to observe contrast between different types of macromolecules. Different chemical exchange times were obtained for the different tissues.
For blood vessels, we were not able yet to observe structural changes of the arteries that we investigated since all of them were of healthy animals. Moreover – all samples belonged to relatively young animals, as samples of old animals were not available. Our purpose is to test post mortem human arteries, or to cooperate with a local hospital in order to verify the usefulness of the method in characterizing plaque and other diseases of the arterial wall. When we will be able to investigate human aged blood vessels, or blood vessels with plaque it might be possible to differentiate between vulnerable and non-vulnerable plaque with a better contrast using that new method, which already proved to be macromolecule-type sensitive.
Despite of the very fast relaxation time of the protein, we are able to receive a signal with reasonable signal to noise ratio, which is based on the macromolecule magnetization.
We have also verified that it is possible to implement the method with clinical pulses - meaning – with long pulses and low power. Such pulses are safe to be used on patients. Pulses length was 500?sec. Results were very similar to those achieved with “hard pulses”.