Quantitative MRI Techniques in Regional Myocardial Function

Magnetic resonance imaging (MRI) not only depicts anatomical details, but can be sensitized to the movement and deformation of soft tissues such as the muscle of the heart and can provide measurements of tissue motion at high resolution. A particularly useful class of methods for assessing the contractile function of the myocardial wall is displacement imaging. Magnetic resonance (MR) displacement imaging measures the change of position of tissue elements over a period of time starting from a reference time-point. In concept, it is similar to tracking the three-dimensional (3D) movement of implanted radio-opaque markers in cine fluoroscopy, but instead of using extraneous markers, controlled modulations of various aspects of tissue proton magnetization are utilized as noninvasive markers. Advances in phase modulation techniques allow all pixels of an image to be tracked simultaneously and therefore give high-density measurements of tissue motion.