The acquired echo trains from different direction and different radial depth are in good quality.
NMR logging interpretation is based on the inverted T2 distributions from acquired echo trains.
For the functional scanning the following parameters were used: repetition time: 1512 ms for three subjects and 1500 ms for the remaining subjects (31 slices acquired), echo time: 30 ms, flip angle: 70 degrees, field of view: 22×22 cm, 64×64 matrix and 4.65 mm slice thickness.
To improve image quality, 4 gradient echoes were acquired (echo delay times (TE) = 2.2, 4.75, 7.3, 9.85 ms) after each excitation pulse.
We show that RF filtering has a dramatic effect on the overall signal-to-fluctuation-noise ratio (SfNR) of the acquired echo-planar imaging data.
The scanner acquired echo-planar-imaging (EPI) sequences using fast gradients.
In fat-suppressed spoiled gradient-echo pulse sequences, data acquisition is divided into segments, each preceded by a spectrally selective inversion pulse and containing several successively acquired echoes.
This technique combines six asymmetrically acquired echoes with parallel imaging with an iterative least-squares decomposition algorithm to maximize noise performance.
Functional imaging was conducted using a 3.0-Tesla GE Signa scanner with an eight channel phase array head coil to acquire gradient echo T2*-weighted echo-planar images as previously described [ 35, 36].
Unlike rectilinear k-space sampling, BLADE uses a turbo spin echo (TSE) sequence to acquire multiple echo trains (BLADEs) in a rotating, partially overlapping fashion (Fig. 1).
A 3 Tesla MR head scanner (Magnetom Allegra, Siemens, Erlangen, Germany) was used to acquire gradient echo T 2 * -weighted echo-planar images (EPI) with blood oxygen level dependent contrast (time echo = 30 ms, time repetition = 1.43 s, flip angle = 70°, slice tilt = 30°, z-shim gradient prepulse = −1 mT/m ms).
