
Proceedings Paper
Statistics of MR signals: revisitedFormat | Member Price | Non-Member Price |
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Paper Abstract
A common view in MRI research is that the object variability of MR signals
is negligible. With this recognition, the signal components of MR signals
are treated as constant and the noise components are studied as random
processes. Because signal components of MR signals represent a collective
behavior of a huge mount of spins, a statistical investigation may provide
a better understanding of MR signals. The work reported in this paper first
investigates statistics of the thermal equilibrium bulk magnetization (TEMM)
which is the quantity to be imaged - one that can be measured and actually
observed in MRI. Then it investigates statistics of the transverse precessing
bulk magnetization (TPMM) which introduce an electromagnetic force in the
receiver coil of MRI. Finally this study investigates statistics of signal
components of three MR signals at the different stages of MR signal detection
module: Free Induction Decay (FID), Phase Sensitive Detection (PSD), and
Analog-to-Digital Conversion (ADC), sequentially. k-space sample is a
reformatted ADC signal. The study derives and proves stochastic models for
TEMM, TPMM, FID, PSD, and ADC signals, also proposes and justifies stochastic
models for homogeneous and inhomogeneous samples. The study shows that under
the normal conditions and the ordinary settings, magnetizations can be
characterized as spatially deterministic processes with Probability one,
and MR signals - signal component plus noise component - can be characterized
as temporal Gaussian random processes with the means of signal components
and the variances of noise components. These means are expressed in closed
forms in terms of parameters of MR imaging system and the samples. The derived
statistical properties of MR signals will serve as the basis for evaluating
performances of imaging system and studying statistics of the MR image.
Paper Details
Date Published: 19 March 2007
PDF: 12 pages
Proc. SPIE 6510, Medical Imaging 2007: Physics of Medical Imaging, 651052 (19 March 2007); doi: 10.1117/12.709388
Published in SPIE Proceedings Vol. 6510:
Medical Imaging 2007: Physics of Medical Imaging
Jiang Hsieh; Michael J. Flynn, Editor(s)
PDF: 12 pages
Proc. SPIE 6510, Medical Imaging 2007: Physics of Medical Imaging, 651052 (19 March 2007); doi: 10.1117/12.709388
Show Author Affiliations
Tianhu Lei, Univ. of Pennsylvania (United States)
Published in SPIE Proceedings Vol. 6510:
Medical Imaging 2007: Physics of Medical Imaging
Jiang Hsieh; Michael J. Flynn, Editor(s)
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