These images were used to create a pseudocolour sensitized FRET image for each time point using specific algorithms.
Le Bihan and colleagues [20] hypothesized that for functional imaging of gray matter diffusion-sensitized images can be used to measure neuronal activity-related cell swelling.
MR images sensitized to changes in BOLD signal levels were obtained by an echo planar imaging sequence on a 3.0-Tesla Siemens MR scanner (repetition time = 2,000 msec; echo time = 30 msec; flip angle = 90°, matrix = 64×64; field of view = 220×220 mm2; slice thickness = 3 mm; slice gap = 1 mm and, thus, acquisition voxel size = 3.4×3.4×4 mm3.4×3.4×4
SNR was optimized when the ratio of diffusion-sensitized to non-sensitized images was 9.13 for GA and tGA, 10.57 for FA, 9.17 for RA, and 26 for MD and VR.
Eight volumes without diffusion weighting (b = 0 smm−2) were followed by 25 diffusion-sensitized images with gradients applied in non-collinear directions (b = 1000 smm).
Acquired diffusion sensitized and reference image sets were transferred to an Intel Pentium, Microsoft windows based operating system for further data analysis.
Through-plane PC-MR images are sensitized to velocity values between ± V enc, the encoding velocity.
In order to evaluate the sensitized emission through FRET, images were taken exciting the sample with the 488 nm line and collecting emission between 566 and 680 nm.
A reduced encoding DTI methodology (Jiang et al. 2004) was employed, such that each dataset consisted of a fully encoded 512 × 256 × 256 (readout × phase × slice) matrix-size b0 (i.e., b ≈ 0) and 12 reduced encoded (512 × 128 × 128) diffusion-weighted images (DWI) sensitized in each of an optimized set of 12 directions (Papadakis et al. 1999).
In 1860 the phototransfer process was patented, enabling a photographic image on sensitized paper to be inked and transferred to the printing surface.
A major limitation of diffusion sensitized SS-EPI imaging is magnetic susceptibility artifacts, at different tissue interfaces common in musculoskeletal imaging, such as bone and soft tissue, which can lead to severe geometric image distortion, relatively low spatial resolution due to rapid T2* decay of signal, and in general low image quality.
