Atlas-Based Adaptive Hadamard-Encoded MR Spectroscopic Imaging at 3T.

BACKGROUND: This study aimed to develop a time-efficient method of acquiring simultaneous, dual-slice MR spectroscopic imaging (MRSI) for the evaluation of brain metabolism. METHODS: Adaptive Hadamard-encoded pulses were developed and integrated with atlas-based automatic prescription. The excitation profiles were evaluated via simulation, phantom and volunteer experiments. The feasibility of γ-aminobutyric acid (GABA)-edited dual-slice MRSI was also assessed. RESULTS: The signal between slices in the dual-band MRSI was less than 1% of the slice profiles. Data from a homemade phantom containing separate, interfacing compartments of creatine and acetate solutions demonstrated ~0.4% acetate signal contamination relative to the amplitude in the excited creatine compartment. The normalized signal-to-noise ratios from atlas-based acquisitions in volunteers were found to be comparable between dual-slice, Hadamard-encoded MRSI and 3D acquisitions. The mean and standard deviation of the coefficients of variation for NAA/Cho from the repeated volunteer scans were 8.2% ± 0.8% and 10.1% ± 3.7% in the top and bottom slices, respectively. GABA-edited, dual-slice MRSI demonstrated simultaneous detection of signals from GABA and coedited macromolecules (GABA+) from both superior grey and deep grey regions of volunteers. CONCLUSION: This study demonstrated a fully automated dual-slice MRSI acquisition using atlas-based automatic prescription and adaptive Hadamard-encoded pulses.

Attendance of DSCTCA / 医疗卫生装备

Objective To investigate attendance of DSCTCA (dual-slice spiral CT coronary angiography). Methods Data from 463 patients undergoing DSCTCA were obtained and anylyzed. Results 451 cases are successfully examined at one time and 12 are failed. 8 in these 12 cases cannot hold their breath and the other 4 patients are due to unsatisfying heart rate. Better images are obtained when the 12 patients are examined again. All of the patients do not have harmful reactions and unexpected complications. Conclusion Excellent images can be obtained with DSCTCA at any heart rate without beta-receptors blocks before examination. The trunk and brunch of coronary artery can be displayed clear. Good attendence is important and guarantee the examination.