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Robust and high resolution hyperpolarized metabolic imaging of the rat heart at 7 T with 3D spectral-spatial EPI.

Miller JJ, Lau AZ, Teh I, Schneider JE, Kinchesh P, Smart S, Ball V, Sibson NR, Tyler DJ - Magn Reson Med (2015)

Bottom Line: Significant differences in myocardial pyruvate dehydrogenase flux were observed between the three groups of animals, concomitant with the known biochemistry.The field of view enabled the simultaneous multi-organ acquisition of metabolic information from the rat, which is of great utility for preclinical research in cardiovascular disease.Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics, Clarendon Laboratory, University of Oxford, England, UK.

No MeSH data available.


Related in: MedlinePlus

a: The distributions of gated shot TR was distributed around the R–R interval (here ≈ 170 ms), with a small number of missed triggers (at ≈ 350 ms). b: As expected for a stochastic waiting process, the subsequent distribution of image TR was described by a gamma distribution (fit), with a large spread in values (min/max TR/image = 1.966 s / 2.418 s). c: The error between the expected (N × R–R interval) and measured scan times becomes progressively worse as time increases.
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Figure 8: a: The distributions of gated shot TR was distributed around the R–R interval (here ≈ 170 ms), with a small number of missed triggers (at ≈ 350 ms). b: As expected for a stochastic waiting process, the subsequent distribution of image TR was described by a gamma distribution (fit), with a large spread in values (min/max TR/image = 1.966 s / 2.418 s). c: The error between the expected (N × R–R interval) and measured scan times becomes progressively worse as time increases.

Mentions: A slight distribution of acquisition TRs was observed (Fig. 8a), with a large peak at the R–R interval and a small number of shots at 2 × R–R interval, reflecting a number of missed triggers that we conjecture are due to respiratory motion. It was noted that the TR of the experiment was not constant, and that the distribution of 3D image TRs was well described by a gamma distribution (Fig. 8). The mean of this distribution was not equal to the number of z phase encodes, N × the R–R interval. The observed coefficient of variation of TR/image was 40.4±11.4% (distribution σ/μ ± S.E.M. over 16 scans), reflecting a significant variability in the R–R interval of the anaesthetized rat. We are confident that this effect is biological in origin and not an experimental artefact; the variability vanished when a signal generator was used to provide an input comparable to an ECG into our cardiac triggering hardware. We note that the correct time axis is fundamentally important in hyperpolarized imaging, as it is desirable to create quantitative maps of metabolic rate constants of interest.


Robust and high resolution hyperpolarized metabolic imaging of the rat heart at 7 T with 3D spectral-spatial EPI.

Miller JJ, Lau AZ, Teh I, Schneider JE, Kinchesh P, Smart S, Ball V, Sibson NR, Tyler DJ - Magn Reson Med (2015)

a: The distributions of gated shot TR was distributed around the R–R interval (here ≈ 170 ms), with a small number of missed triggers (at ≈ 350 ms). b: As expected for a stochastic waiting process, the subsequent distribution of image TR was described by a gamma distribution (fit), with a large spread in values (min/max TR/image = 1.966 s / 2.418 s). c: The error between the expected (N × R–R interval) and measured scan times becomes progressively worse as time increases.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4556070&req=5

Figure 8: a: The distributions of gated shot TR was distributed around the R–R interval (here ≈ 170 ms), with a small number of missed triggers (at ≈ 350 ms). b: As expected for a stochastic waiting process, the subsequent distribution of image TR was described by a gamma distribution (fit), with a large spread in values (min/max TR/image = 1.966 s / 2.418 s). c: The error between the expected (N × R–R interval) and measured scan times becomes progressively worse as time increases.
Mentions: A slight distribution of acquisition TRs was observed (Fig. 8a), with a large peak at the R–R interval and a small number of shots at 2 × R–R interval, reflecting a number of missed triggers that we conjecture are due to respiratory motion. It was noted that the TR of the experiment was not constant, and that the distribution of 3D image TRs was well described by a gamma distribution (Fig. 8). The mean of this distribution was not equal to the number of z phase encodes, N × the R–R interval. The observed coefficient of variation of TR/image was 40.4±11.4% (distribution σ/μ ± S.E.M. over 16 scans), reflecting a significant variability in the R–R interval of the anaesthetized rat. We are confident that this effect is biological in origin and not an experimental artefact; the variability vanished when a signal generator was used to provide an input comparable to an ECG into our cardiac triggering hardware. We note that the correct time axis is fundamentally important in hyperpolarized imaging, as it is desirable to create quantitative maps of metabolic rate constants of interest.

Bottom Line: Significant differences in myocardial pyruvate dehydrogenase flux were observed between the three groups of animals, concomitant with the known biochemistry.The field of view enabled the simultaneous multi-organ acquisition of metabolic information from the rat, which is of great utility for preclinical research in cardiovascular disease.Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics, Clarendon Laboratory, University of Oxford, England, UK.

No MeSH data available.


Related in: MedlinePlus