Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Modelling an equivalent b-value in diffusion-weighted steady-state free
  precession   Purpose: Diffusion-weighted steady-state free precession (DW-SSFP) is shown
to provide a means to probe non-Gaussian diffusion through manipulation of the
flip angle. A framework is presented to define an effective b-value in DW-SSFP.
Theory: The DW-SSFP signal is a summation of coherence pathways with different
b-values. The relative contribution of each pathway is dictated by the flip
angle. This leads to an apparent diffusion coefficient (ADC) estimate that
depends on the flip angle in non-Gaussian diffusion regimes. By acquiring
DW-SSFP data at multiple flip angles and modelling the variation in ADC for a
given form of non-Gaussianity, the ADC can be estimated at a well-defined
effective b-value. Methods: A gamma distribution is used to model non-Gaussian
diffusion, embedded in the Buxton signal model for DW-SSFP. Monte-Carlo
simulations of non-Gaussian diffusion in DW-SSFP and diffusion-weighted
spin-echo (DW-SE) sequences are used to verify the proposed framework.
Dependence of ADC on flip angle in DW-SSFP is verified with experimental
measurements in a whole, human post-mortem brain. Results: Monte-Carlo
simulations reveal excellent agreement between ADCs estimated with DW-SE and
the proposed framework. Experimental ADC estimates vary as a function of flip
angle over the corpus callosum of the postmortem brain, estimating the mean and
standard deviation of the gamma distribution as $1.50\cdot 10^{-4} mm^2/s$ and
$2.10\cdot 10^{-4} mm^2/s$. Conclusion: DW-SSFP can be used to investigate
non-Gaussian diffusion by varying the flip angle. By fitting a model of
non-Gaussian diffusion, the ADC in DW-SSFP can be estimated at an effective
b-value, comparable to more conventional diffusion sequences.

35
The categories of this paper are: mtrl-th
1
The categories of this paper are: cs
37
The categories of this paper are: supr-con
16
The categories of this paper are: stat
17
The categories of this paper are: q-fin
24
The categories of this paper are: dg-ga
29
The categories of this paper are: funct-an
12
The categories of this paper are: nucl-th
19
The categories of this paper are: eess
0
The categories of this paper are: hep-ph
31
The categories of this paper are: ao-sci
30
The categories of this paper are: q-alg
9
The categories of this paper are: nlin
15
The categories of this paper are: nucl-ex
8
The categories of this paper are: hep-ex
7
The categories of this paper are: hep-th