Accelerated and KWIC-filtered cardiac T2 mapping for improved precision: proof of principle

Background In recent years, several successful variations of T2-prepared cardiac T2 mapping techniques have been described for the quantification of cardiac edema [1,2,3]. Radial imaging for high-resolution T2 mapping [3] has the advantage of reduced motion sensitivity, but suffers from a lower signal-to-noise ratio (SNR) due to the undersampling of the periphery of k-space and the density compensation function (DCF) that increases the weight of the relatively noisy and less densely sampled k-space periphery (Fig.1a). Since the contrast of an image is defined by the center of k-space, a KWIC (kspace weighted image contrast [4]) filter can be used to share only the periphery among radial images that have the same geometry and different contrast, such as those used to generate a T2 map (Fig.1b). Furthermore, when undersampling is used to acquire more images per T2 map (resulting in more k-space peripheries that can be shared), KWIC filtering further reduces the noise-like undersampling artifacts (Fig.1c). The goal of this study was therefore to test whether the use of the KWIC filter leads to a higher precision in radial T2 maps for a given acquisition time.