T1-weighted (T1w) (repetition time [TR] = 1860 msec; echo time [TE] = 2.8 msec; inversion time [TI] = 1100 msec; flip angle [FA] = 10°; voxel size = 0.9 mm isotropic) and a pair of gradient recalled echo volumes with/without a magnetization transfer prepulse (MTON and MTOFF: TR = 24 msec; TE = 3.81 msec; FA = 10°; voxel size = 1 mm isotropic) for MTR calculation were acquired.
T1-weighted magnetization prepared rapid-acquisition gradient echo volumes in the sagittal plane will be acquired with an echo time of 3.21 ms and repetition time 2100 ms; 96 sagittal slices of 1.3 mm thickness will be acquired with a 160 mm field of view, a flip angle of 9°, and a 128 × 128 matrix, resulting in voxel sizes of 1.25 × 1.25 × 1.3 mm.
"Don't give me that laissez-faire," he told the offensive line, and went on, using language more colorful, at an echoing volume.
The main hardware circuit and software design of speech communication system were analyzed, speech signal was inset comfortable noise, eliminated echo, controlled volume, finally through the system debugging and channel pool test.
For each subject a T1-weighted anatomical (three-dimensional magnetization prepared rapid acquisition gradient echo, MPRAGE) volume (1×1×1 mm voxels) was acquired under anesthesia in a separate session.
An inversion recovery-prepared 3D spoiled gradient echo 'T1 volume' scan was obtained with an image matrix of 256 × 256 × 196 voxels, giving an isotropic voxel size of 1.1 mm (echo time/repetition time/inversion time = 2.8/6.6/450 ms, flip angle 20°).
High-resolution sagittal 3D T1-weighted Magnetization prepared rapid gradient-echo (MPRAGE) volume (voxel size 1.1 × 1.1 × 1.2 mm³) and axial proton density/T2-weighted fast spin echo images were acquired on 1.5 T MRI scanners for 476 of the subjects (179 control, 123 MCI, and 174 AD) as previously reported [13].
This protocol produced 180 echo planar volumes in one series (duration 7.5 min).
We defined the VEEC depth (ZVEEC) to be the depth where 98% of the cumulated sum of acoustic echoes (Sv, Volume backscattering strength, in dB re 1 m−1) from the epipelagic community was reached (the cumulated sum is integrated downward from the surface).
