TITLE:
Apparent Diffusion Coefficient Mapping Using a Multi-Shot Spiral MRI Sequence of the Rat Brain
AUTHORS:
Tomokazu Numano, Koji Hyodo, Naotaka Nitta, Junichi Hata, Nobuaki Iwasaki, Kazuhiro Homma
KEYWORDS:
Diffusion Weighted Imaging (DWI); Echo Planner Imaging (EPI); Spiral MRI Sequence; Apparent Diffusion Coefficient (ADC)
JOURNAL NAME:
Open Journal of Radiology,
Vol.4 No.1,
February
18,
2014
ABSTRACT: Purpose: Commonly used diffusion weighted (DW) imaging
such as DW spin echo (SE) type echo planar imaging (DW-SE-EPI) is known to be a
snapshot-like acquisition and to have a relatively high signal-to-noise ratio. Spiral
MRI sequence (SPIRAL) has characteristics similar to these of EPI, but it has
rarely been used for diffusion-weighted imaging (DWI). In vivo DW-SPIRAL of the rat brain has almost never been reported.
Our purpose in this study was to examine the potential of SE-type
two-dimensional (2D) multi-shot spiral acquisition MRI for apparent diffusion
coefficient (ADC) mapping of the rat brain in
vivo. Materials and Methods: We made an SE-type DW-2D-spiral MRI sequence
(DW-SPIRAL) which was prepared on a 2.0-T animal-experiment MR scanner. Comparing
the phantom experimental result of DW-SPIRAL with the phantom experimental
result of DW SE-type echo-planar imaging (DW-SE-EPI) and conventional DW spin
echo imaging (DW-SE), we estimated the characteristics of DW-SPIRAL and
assessed the clinical application of DW-SPIRAL in an animal experiment on the
rat brain. Results: There was not much difference between the calculated
water/glycerol phantom diffusion coefficient of DW-SPIRAL and the calculated
diffusion coefficient of DW-SE. This result shows that the DW-SPIRAL sequence
is appropriate for use in diffusion weighted imaging. There were fewer phantom
image distortions and ghosting artifacts with DW-SPIRAL than with DW-SE-EPI,
and this tendency was similar in the animal experiment on the rat brain. Conclusion:
The DW-SPIRAL sequence had been successfully tested in phantom experiments and
rat brain experiments. It has been demonstrated that the DW-SPIRAL sequence is
capable of producing in vivo rat
brain DWI.