Fig. 2

Quantitative Determination of Myocardial T2 Relaxation Time. In order to generate quantitative maps of myocardial T2 relaxation time, several images with varying T2 sensitivity are acquired at the same cardiac phase over multiple cardiac cycles. For each pixel location, the signal intensities across the T2 weighted (T2w) images are then fit to a mono-exponential decay equation to estimate the T2 relaxation time and generate a T2 map. These maps are often displayed using a color scale for easier visualization. The graph demonstrates the transverse signal decay of myocardium and arterial blood, as measured from the three single-shot T2 prepared balanced steady state free precession (bSSFP) images acquired at T2 preparation times of 0, 25 and 55 ms. Since myocardial T2 relaxation time is approximately four times shorter than arterial blood, this difference is observed in the faster signal decay in the myocardium across the T2w images and in the color map. Placing a region of interest in the map provides the user with the corresponding T2 relaxation time