Radial T2 mapping with the KWIC filter. a) Example of a T2 map of the phantom, with a homogeneous T2 in blue-green circular compartment that has relaxation times similar to those of the myocardium. b) Results of the different T2 mapping techniques in the phantoms. The KWIC-filtered image that uses ~36% of the radial lines (and thus 72% of the acquisition time) has a significantly lower T2 standard deviation. c and d) Short-axis cardiac T2 maps in volunteers demonstrate equivalency of the undersampled images.