Task: Intent Identification
Input (English): Displacement Encoding with Stimulated Echoes (DENSE) encodes displacement into the phase of the magnetic resonance signal. The encoding frequency (ke) maps the measured phase to tissue displacement while the strength of the encoding gradients affects image quality. 2D cine DENSE studies have used a ke of 0.10\xa0cycles/mm, which is high enough to remove an artifact-generating echo from k-space, provide high sensitivity to tissue displacements, and dephase the blood pool. However, through-plane dephasing can remove the unwanted echo and dephase the blood pool without relying on high ke. Additionally, the high sensitivity comes with the costs of increased phase wrapping and intra-voxel dephasing. We hypothesized that ke below 0.10\xa0cycles/mm can be used to improve image characteristics and provide accurate measures of cardiac mechanics.', 'Spiral cine DENSE images were obtained for 10 healthy subjects and 10 patients with a history of heart disease on a 3\xa0T Siemens Trio. A mid-ventricular short-axis image was acquired with different ke: 0.02, 0.04, 0.06, 0.08, and 0.10\xa0cycles/mm. Peak twist, circumferential strain, and radial strain were compared between acquisitions employing different ke using Bland-Altman analyses and coefficients of variation. The percentage of wrapped pixels in the phase images at end-systole was calculated for each ke. The dephasing of the blood signal and signal to noise ratio (SNR) were also calculated and compared.', 'Negligible differences were seen in strains and twist for all ke between 0.04 and 0.10\xa0cycles/mm. These differences were of the same magnitude as inter-test differences. Specifically, the acquisitions with 0.04\xa0cycles/mm accurately quantified cardiac mechanics and had zero phase wrapping. Compared to 0.10\xa0cycles/mm, the acquisitions with 0.04\xa0cycles/mm had 9\xa0% greater SNR and negligible differences in blood pool dephasing.
Output (English): 0