Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Inverse Z-spectrum analysis for MT- and spillover-corrected and
  T1-compensated steady-state pulsed CEST-MRI - application to pH-weighted MRI
  of acute stroke   Endogenous chemical exchange saturation transfer (CEST) effects are always
diluted by competing effects such as direct water proton saturation (spillover)
and macromolecular magnetization transfer (MT). This leads to T2-and
MT-shine-through effects in the actual biochemical contrast of CEST. Therefore,
a simple evaluation algorithm which corrects the CEST signal was searched for.
By employing a recent eigenspace theory valid for spinlock and continuous wave
(cw) CEST we predict that the inverse Z-spectrum is beneficial to Z-spectrum
itself. Based on this we propose a new spillover- and MT-corrected
magnetization transfer ratio (MTRRex) yielding Rex, the exchange dependent
relaxation rate in the rotating frame. For verification, the amine proton
exchange of creatine in solutions with different agar concentration was studied
experimentally at clinical field strength of 3T. In contrast to the compared
standard evaluation for pulsed CEST experiments, MTRasym, our approach shows no
T2 or MT shine through effect. We demonstrate that spillover can be corrected
properly and also quantitative evaluation of pH and creatine concentration is
possible which proves MTRRex as quantitative CEST-MRI method. A spillover
correction is of special interest for clinical static field strengths and
protons resonating near the water peak. This is the case for -OH-CEST effects
like gagCEST or glucoCEST, but also amine exchange of creatine or glutamate
which require high B1. Although, only showed for amine exchange, we propose our
normalization to work generally for DIACEST, PARACEST in slow- and fast
exchange regime not just as a correction, but also for quantitative CEST-MRI.
Applied to acute stroke induced in rat brain, the corrected CEST signal shows
significantly higher contrast between stroke area and normal tissue as well as
less B1 dependency compared to conventional approaches.

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The categories of this paper are: math-ph
7
The categories of this paper are: hep-th
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The categories of this paper are: patt-sol
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The categories of this paper are: q-fin
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The categories of this paper are: dg-ga
36
The categories of this paper are: cmp-lg
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The categories of this paper are: cs
4
The categories of this paper are: cond-mat
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The categories of this paper are: math
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The categories of this paper are: econ
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The categories of this paper are: solv-int
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The categories of this paper are: atom-ph
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The categories of this paper are: plasm-ph
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The categories of this paper are: q-bio
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The categories of this paper are: hep-ph
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The categories of this paper are: supr-con