for providing samples of rubber. “
“The above mentioned paper did not include any acknowledgment to co-author Lucy Waskell’s funding source agency. learn more The funding source which was inadvertently omitted is as follows: Veterans Administration Merit Review Grant. “
“The above mentioned paper did not include any acknowledgment to co-author Lucy Waskell’s funding source agency. The funding source which was inadvertently omitted is as follows: Veterans Administration Merit Review Grant. “
“Diffusion-weighted

imaging (DWI) and diffusion-tensor imaging (DTI) are non-invasive MRI techniques with broad clinical applications. While many clinical applications of diffusion imaging are in the brain, there is an increasing number of DWI and DTI studies in other organs [1], including the spinal cord [2], breast [3], prostate [4], liver [5], kidney [6], pancreas [7] and in the heart [8] and [9]. Bulk physiological motion has initially been a barrier to performing diffusion imaging in organs affected by motion. In cardiac selleck chemicals llc diffusion, this has been alleviated by technical advances including the use of cardiac/respiratory navigator techniques, single-shot echo planar imaging (EPI) readouts, and sequence modifications that reduce the effects of any motion that occurs

during the diffusion gradients. Such techniques have improved the robustness and reproducibility of diffusion-imaging applications in moving organs such as cardiac DTI [8] and [9]. Unfortunately, diffusion imaging suffers from substantial artifacts such as those caused by eddy currents, which are induced in conducting structures of the magnet bore by gradient switching. Diffusion selleck chemical imaging is particularly prone to eddy-current artifacts due to relatively long EPI readouts combined with strong

diffusion-sensitizing gradients. Unlike static field inhomogeneities, eddy currents do not remain constant over diffusion-encoding directions. Rather, they vary depending upon the magnitude and direction of the applied diffusion gradients. This leads to spatial misregistration and inconsistency between uncorrected images obtained with different diffusion-encoding directions or b-values. Ignoring eddy currents in the image reconstruction results in ghosting, bulk object shifts and deformations, as well as signal dropouts [10]. In DTI, this also leads to inaccuracies in estimates of the fractional anisotropy (FA). In this study, we investigate the effects of eddy currents in sequences that are suitable for performing cardiac DTI where there is substantial motion. Two sequences previously used for cardiac diffusion are compared: (i) the Stejskal-Tanner or “unipolar” spin-echo diffusion sequence [11] and (ii) a “bipolar” spin-echo sequence [12], [13] and [14]. The unipolar sequence has a shorter echo time (TE) while the bipolar sequence offers insensitivity to first-order bulk motion through its velocity-compensated nature [12], [13] and [14]. The twice-refocused sequence, described in Reese et al.