The sensitivity of the zeugmatographic experiment involving human samples

Hoult, D. I.; Lauterbur, Paul C.

doi:10.1016/0022-2364(79)90019-2

Cited by 562 publications

(540 citation statements)

References 3 publications

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“…However, unlike conventional MRI, the strong field is not needed here to polarize the gas. Futhermore, if experimental noise is dominated by electrical losses in the body it scales linearly with frequency [7], and because the inductive NMR signal does so as well, the signal to noise ratio (SNR) is independent of field and there exists no benefit to performing HG imaging at high fields in that respect. This was confirmed at 0.1 T by the research group at Orsay using a Sopha-imaging-Magnetech MRI unit [8,9].…”

Section: Introductionmentioning

confidence: 99%

In vivo NMR of hyperpolarized 3He in the human lung at very low magnetic fields

Bidinosti¹,

Choukeife²,

Nacher³

et al. 2003

Journal of Magnetic Resonance

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We present NMR measurements of the diffusion of hyperpolarized 3 He in the human lung performed at fields much lower than those of conventional MRI scanners. The measurements were made on standing subjects using homebuilt apparatus operating at 3 mT. O 2 -limited transverse relaxation (T 2 up to 15-35 s) could be measured invivo. Accurate global diffusion measurements have been performed in-vivo and in a plastic bag; the average apparent diffusion coefficient (ADC) in-vivo was 14.2 ± 0.6 mm 2 /s, whereas the diffusion coefficient in the bag ( 3 He diluted in N 2 ) was 79.5 ± 1 mm 2 /s. 1D ADC mapping with high SNR (∼ 200 -300) demonstrates the real possibility of performing quality lung imaging at extremely low fields.

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Section: Introductionmentioning

confidence: 99%

In vivo NMR of hyperpolarized 3He in the human lung at very low magnetic fields

Bidinosti¹,

Choukeife²,

Nacher³

et al. 2003

Journal of Magnetic Resonance

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“…When imaging even earlier-stage embryos than we have considered here (i.e., E9.5-E13.5), the sample noise decreases more rapidly than the coil noise with respect to dimensional size: the sample noise variance scales with dimension to the fifth power, whereas the coil noise variance scales with the square of dimension (14). This will result in MR image noise dominated by coil noise.…”

Section: Discussionmentioning

confidence: 91%

“…If one were to perform mouse embryo imaging at higher field strength (which would be recommended to increase the SNR), since the sample resistance is proportional to the square of field strength, whereas the coil resistance is proportional to the square root of field strength (14), MR image noise will return to the sample-noise-dominated regimen, as is the case for clinical MRI at 1.5-3 T. This will result in the SNR being proportional to the field strength for both the shared and individual methods. Therefore, at a given field strength, the SNR ratio between these two methods will no longer be dependent on the field strength and will be higher than the SNR ratio at lower field strength, as determined in this work.…”

Section: Discussionmentioning

confidence: 99%

“…The sample resistance of a cylindrical sample is R sample ¼pv 2 0 B 2 1 lr 4 = 8r ð Þ, where x 0 ¼ cB 0 is the Larmor frequency, B 1 is the magnetic field induced in the RF coil per unit current, l is the length of the cylindrical sample, r is the radius of the cylindrical sample, and q is the resistivity of the sample (14). It can be seen that the sample resistance R sample is proportional to the square of field strength.…”

Section: Snr Compensationmentioning

confidence: 99%

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Comparative SNR for high‐throughput mouse embryo MR microscopy

Zhang

Schneider

Portnoy

et al. 2010

Magnetic Resonance in Med

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MR microscopy is being explored as a useful imaging tool to phenotype mouse embryos due to its volume coverage with three‐dimensional isotropic resolution. However, the main limitation for mouse embryo MR microscopy is the signal‐to‐noise ratio. Large numbers of embryos are needed for phenotypic screening, making high throughput essential. Two high‐throughput imaging approaches, multi‐embryo shared‐coil (shared) and multi‐embryo individual‐coil (individual), have been developed for phenotyping mouse embryos. This study quantitatively compares the signal‐to‐noise ratio at equivalent times between these two established methods by compensating for differences that result from field strength. While the individual method provides 3.3 times as much signal‐to‐noise ratio as the shared method at equivalent conditions, it is more difficult and expensive to implement. Furthermore, the number of embryos that can be imaged concurrently is limited by the number of receiver channels. The objective of this study is to provide measured comparative data to guide choices for high‐throughput mouse embryo MR microscopy and other similar applications. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.

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“…The spatially dependent SNR of parallel single-shot DW EPI in combination with SE and STE acquisition, respectively, is given as (11,20,21):…”

Section: Theorymentioning

confidence: 99%

Optimizing signal‐to‐noise ratio of high‐resolution parallel single‐shot diffusion‐weighted echo‐planar imaging at ultrahigh field strengths

Reischauer

Vorburger

Wilm

et al. 2011

Magnetic Resonance in Med

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The potential signal-to-noise ratio (SNR) gain at ultrahigh field strengths offers the promise of higher image resolution in single-shot diffusion-weighted echo-planar imaging the challenge being reduced T 2 and T 2 * relaxation times and increased B 0 inhomogeneity which lead to geometric distortions and image blurring. These can be addressed using parallel imaging (PI) methods for which a greater range of feasible reduction factors has been predicted at ultrahigh field strengths-the tradeoff being an associated SNR loss. Using comprehensive simulations, the SNR of high-resolution diffusion-weighted echo-planar imaging in combination with spinecho and stimulated-echo acquisition is explored at 7 T and compared to 3 T. To this end, PI performance is simulated for coil arrays with a variable number of circular coil elements. Beyond that, simulations of the point spread function are performed to investigate the actual image resolution. When higher PI reduction factors are applied at 7 T to address increased image distortions, high-resolution imaging benefits SNR-wise only at relatively low PI reduction factors. On the contrary, it features generally higher image resolutions than at 3 T due to smaller point spread functions. The SNR simulations are confirmed by phantom experiments. Finally, high-resolution in vivo images of a healthy volunteer are presented which demonstrate the feasibility of higher PI reduction factors at 7 T in practice. Magn Reson Med 67:679-690, 2012. V C 2011 Wiley Periodicals, Inc.Key words: high-resolution diffusion-weighted imaging; echoplanar imaging; signal-to-noise ratio; parallel imaging; ultrahigh field strengths Diffusion-weighted imaging is a powerful noninvasive magnetic resonance imaging technique that relies on the measurement of the restricted Brownian motion of water molecules to deduce microscopic tissue structure in vivo. Although the biophysical basis is not clearly understood, quantitative measures can be derived that exhibit biomarkers in various pathological states, the most prominent being ischemic stroke (1). Diffusion-weighted imaging is clinically promising since the acquisition is noninvasive, relatively fast and requires neither contrast agents nor ionizing radiation. In addition, dedicated tracking algorithms have been developed that allow for the reconstruction of virtual fiber pathways in the human brain which enable presurgical planning and image-guided surgery (2,3).Great potential arises for diffusion-weighted imaging at ultrahigh field strengths through the theoretically associated signal-to-noise ratio (SNR) gain which offers the promise of higher achievable image resolution. Recently, ultrahigh field scanners with 7 T have been introduced to the scientific community. Yet, diffusion-weighted imaging at 7 T is hampered by increased B 0 inhomogeneity which scales linearly with the main magnetic field strength as well as faster T 2 and T 2 * decay. Image acquisition typically relies on single-shot diffusion-weighted (DW) echo-planar imaging (EPI) due to its spe...

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The sensitivity of the zeugmatographic experiment involving human samples

Cited by 562 publications

References 3 publications

In vivo NMR of hyperpolarized 3He in the human lung at very low magnetic fields

In vivo NMR of hyperpolarized 3He in the human lung at very low magnetic fields

Comparative SNR for high‐throughput mouse embryo MR microscopy

Optimizing signal‐to‐noise ratio of high‐resolution parallel single‐shot diffusion‐weighted echo‐planar imaging at ultrahigh field strengths

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