Theoretical signal-to-noise ratio and spatial resolution dependence on the magnetic field strength for hyperpolarized noble gas magnetic resonance imaging of human lungs

BackgroundThe development and clinical adoption of quantitative imaging biomarkers (radiomics) has established the need for the identification of parameters altering radiomics reproducibility. The aim of this study was to assess the impact of magnetic field strength on magnetic resonance imaging (MRI) radiomics features in neuroradiology clinical practice.MethodsT1 3D SPGR sequence was acquired on two phantoms and 10 healthy volunteers with two clinical MR devices from the same manufacturer using two different magnetic fields (1.5 and 3T). Phantoms varied in terms of gadolinium concentrations and textural heterogeneity. 27 regions of interest were segmented (phantom: 21, volunteers: 6) using the LIFEX software. 34 features were analyzed.ResultsIn the phantom dataset, 10 (67%) out of 15 radiomics features were significantly different when measured at 1.5T or 3T (student’s t-test, p < 0.05). Gray levels resampling, and pixel size also influence part of texture features. These findings were validated in healthy volunteers.ConclusionsAccording to daily used protocols for clinical examinations, radiomic features extracted on 1.5T should not be used interchangeably with 3T when evaluating texture features. Such confounding factor should be adjusted when adapting the results of a study to a different platform, or when designing a multicentric trial.

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Estimates of locus coeruleus function with functional magnetic resonance imaging are influenced by localization approaches and the use of multi-echo data

10.1101/731620 ◽

2019 ◽

Cited By ~ 4

Author(s):

Hamid B. Turker ◽

Elizabeth Riley ◽

Wen-Ming Luh ◽

Stan J. Colcombe ◽

Khena M. Swallow

Keyword(s):

Magnetic Resonance Imaging ◽

Time Series ◽

Magnetic Resonance ◽

Functional Magnetic Resonance Imaging ◽

Locus Coeruleus ◽

Signal To Noise Ratio ◽

Fmri Data ◽

Functional Magnetic Resonance ◽

Resonance Imaging ◽

Signal To Noise

AbstractThe locus coeruleus (LC) plays a central role in regulating human cognition, arousal, and autonomic states. Efforts to characterize the LC’s function in humans using functional magnetic resonance imaging have been hampered by its small size and location near a large source of noise, the fourth ventricle. We tested whether the ability to characterize LC function is improved by employing neuromelanin-T1 weighted images (nmT1) for LC localization and multi-echo functional magnetic resonance imaging (ME-fMRI) for estimating intrinsic functional connectivity (iFC). Analyses indicated that, relative to a probabilistic atlas, utilizing nmT1 images to individually localize the LC increases the specificity of seed time series and clusters in the iFC maps. When combined with independent components analysis (ME-ICA), ME-fMRI data provided significant gains in the temporal signal to noise ratio relative to denoised single-echo (1E) data. The effects of acquiring nmT1 images and ME-fMRI data did not appear to only reflect increases in power: iFC maps for each approach only moderately overlapped. This is consistent with findings that ME-fMRI offers substantial advantages over 1E data acquisition and denoising. It also suggests that individually identifying LC with nmT1 scans is likely to reduce the influence of other nearby brainstem regions on estimates of LC function.HighlightsManual tracing of locus coeruleus increased specificity of seed time seriesManual tracing of locus coeruleus increased specificity of intrinsic connectivityMulti-echo fMRI increased temporal signal-to-noise ratio compared to single-echo fMRIConnectivity maps across methodologies overlapped only moderatelyMeasurement of LC function benefits from multi-echo fMRI and tracing ROIs

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Quantitative assessment of phased array coils with different numbers of receiving channels in terms of signal-to-noise ratio and spatial noise variation in magnetic resonance imaging

PLoS ONE ◽

10.1371/journal.pone.0219407 ◽

2019 ◽

Vol 14 (7) ◽

pp. e0219407 ◽

Cited By ~ 1

Author(s):

Kyoung-Nam Kim ◽

Daniel Hernandez ◽

Jeung-Hoon Seo ◽

Young Noh ◽

Yeji Han ◽

...

Keyword(s):

Magnetic Resonance Imaging ◽

Magnetic Resonance ◽

Quantitative Assessment ◽

Phased Array ◽

Signal To Noise Ratio ◽

Resonance Imaging ◽

Signal To Noise ◽

Spatial Noise ◽

Phased Array Coils ◽

Array Coils

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A Novel System for Patient Ventilation and Dosing of Hyperpolarized 3He for Magnetic Resonance Imaging of Human Lungs

Applied Sciences ◽

10.3390/app10093163 ◽

2020 ◽

Vol 10 (9) ◽

pp. 3163

Author(s):

Robert Kordulasiński ◽

Marta Królewska ◽

Bartosz Głowacz ◽

Lutosława Mikowska ◽

Zbigniew Olejniczak ◽

...

Keyword(s):

Magnetic Resonance Imaging ◽

Magnetic Resonance ◽

Lung Volume ◽

Human Lung ◽

Noble Gas ◽

Lung Imaging ◽

Resonance Imaging ◽

Human Lungs ◽

Hyperpolarized 129Xe ◽

Breath Cycle

A versatile ventilator for controlling a patient’s breath cycle and dosing 3He gas has been designed and constructed. It is compatible with a medical magnetic resonance imaging scanner and can be incorporated into routine human lungs imaging procedure that employs hyperpolarized noble gas as a contrast agent. The system adapts to the patient’s lung volume and their breath cycle rhythm, providing maximum achievable comfort during the medical examination. Good quality magnetic resonance lung images of healthy volunteers were obtained. The system has the capability of recycling the exhaled gas to recover the expensive 3He isotope, and can be also adapted to human lung imaging with hyperpolarized 129Xe.

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