Paired self-compensated spin-lock preparation for improved T1 quantification

Mitrea, Bogdan G.; Krafft, Axel J.; Song, Renming; Loeffler, Ralf B.; Hillenbrand, Claudia M.

doi:10.1016/j.jmr.2016.04.017

Cited by 34 publications

(54 citation statements)

References 40 publications

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“…The RAdial Volumetric Encoding (RAVE) sequence was modified to enable T 1ρ imaging with varying the spin‐lock time. Figure depicts the timing diagram and the k‐space trajectory of the 3D T 1ρ ‐RAVE sequence . The sequence comprises a fat‐suppression module, self‐compensated paired T 1ρ preparation module, a radial 3D gradient‐echo acquisition that follows the “stack‐of‐stars” golden‐angle sampling scheme, and a delay for recovery of the longitudinal magnetization to reduce T 1 contamination.…”

Section: Methodsmentioning

confidence: 99%

Volumetric multicomponent T_1ρ relaxation mapping of the human liver under free breathing at 3T

Sharafi

Baboli

Zibetti

et al. 2019

Magnetic Resonance in Med

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Purpose To develop a 3D sequence for T1ρ relaxation mapping using radial volumetric encoding (3D‐T1ρ‐RAVE) and to evaluate the multi relaxation components in the liver of healthy controls and chronic liver disease (CLD) patients. Methods Fat saturation and T1ρ preparation modules were followed by a train of gradient‐echo acquisitions and T1 restoration delay. The series of T1ρ‐weighted images were fitted using mono‐exponential, bi‐exponential, and stretched‐exponential models. The repeatability and reproducibility of the proposed technique were evaluated on National Institute of Standards and Technology phantom by calculating the coefficient of variation between test‐retest scans on the same scanner and between two different 3T scanners, respectively. Mann‐Whitney U‐test was performed to assess differences in T1ρ components among patients (n = 3) and a control group (n = 10). Results The phantom study showed an error of 8.9% and 11.5% in mono T2 relaxation time measurement relative to the reference on 2 different scanners. The coefficient of variation for test‐retest scans performed on the same scanner was 5.7% and 2.4% for scans performed on 2 scanners. The comparison between healthy controls and CLD patients showed a significant difference (P < .05) in mono relaxation time (P = .002), stretched‐exponential relaxation parameter (P = .04). The Akaike information criteria C criterion showed 2.53 ± 0.9% (2.3 ± 0.3% for CLD) of the voxels are bi‐exponential while in 65.3 ± 5.8% (81.2 ± 0.06% for CLD) of the liver voxels, the stretched‐exponential model was preferred. Conclusion The 3D‐T1ρ‐RAVE sequence allows volumetric, multicomponent T1ρ assessment of the liver during free breathing and can distinguish between healthy volunteers and CLD patients.

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Section: Methodsmentioning

confidence: 99%

Volumetric multicomponent T_1ρ relaxation mapping of the human liver under free breathing at 3T

Sharafi

Baboli

Zibetti

et al. 2019

Magnetic Resonance in Med

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“…Any B 0 or B 1 inhomogeneity causes the magnetization to deviate from the transverse plane, which leads to a complicated magnetization evolution instead of the exponential decay related only to the T 1ρ relaxation time . Several methods have been proposed in the literature to compensate for the field inhomogeneities . The paired spin‐lock pulse method, which was used in this study, tries to self‐compensate the B 1 inhomogeneities by changing the phase of the spin‐lock pulse.…”

Section: Methodsmentioning

confidence: 99%

Biexponential T_1ρ relaxation mapping of human knee cartilage in vivo at 3 T

et al. 2017

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Purpose To demonstrate the feasibility of biexponential T1ρ relaxation mapping of human knee cartilage in-vivo. Methods A 3D customized Turbo-Flash sequence was used to acquire T1ρ-weighted images from healthy volunteers employing a standard 3T MRI clinical scanner. Series of T1ρ-weighted images were fitted using monoexponential as well as biexponential models with two- and four- parametric non-linear approach, respectively. Non-parametric Kruskal-Wallis and Mann-Whitney U statistical tests were used to evaluate the regional relaxation and gender differences respectively with a significance level, p-value of 0.05. Results Biexponential relaxations were detected in the cartilage of all volunteers. Short/long relaxation components of T1ρ were estimated to be 6.9/51.0ms respectively. Similarly, the fractions of short/long T1ρ were 37.6/62.4%. The monoexponential relaxation of T1ρ was 32.6ms. The experiments showed good repeatability with coefficient of variation (CV) of less than 20% Conclusion Biexponential relaxation model better fit to T1ρ relaxation decay than monoexponential model in the knee cartilage(R2.4.1). Biexponential T1ρ components could potentially be used to increase the specificity to detect early osteoarthritis by measuring different water compartments and their fractions.

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“…However, a major challenge to the constant amplitude spin‐lock is its susceptibility to B 1 and B 0 inhomogeneities, which results in failure of spin‐lock and considerable image artifacts and quantification errors. Several methods have been reported to mitigate this problem …”

Section: Introductionmentioning

confidence: 99%

On‐resonance and off‐resonance continuous wave constant amplitude spin‐lock and T_1ρ quantification in the presence of B₁ and B₀ inhomogeneities

Jiang

Chen

2018

NMR in Biomedicine

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Spin-lock MRI is a valuable diagnostic imaging technology, as it can be used to probe the macromolecule environment of tissues. Quantitative T imaging is one application of spin-lock MRI that is reported to be promising for a number of clinical applications. Spin-lock is often performed with a continuous RF wave at a constant RF amplitude either on resonance or off resonance. However, both on- and off-resonance spin-lock approaches are susceptible to B and B inhomogeneities, which results in image artifacts and quantification errors. In this work, we report a continuous wave constant amplitude spin-lock approach that can achieve negligible image artifacts in the presence of B and B inhomogeneities for both on- and off-resonance spin-lock. Under the adiabatic condition, by setting the maximum B amplitude of the adiabatic pulses equal to the B amplitude of spin-lock RF pulse, the spins are ensured to align along the effective field throughout the spin-lock process. We show that this results in simultaneous compensation of B and B inhomogeneities for both on- and off-resonance spin-lock. The relaxation effect during the entire adiabatic half passage (AHP) and reverse AHP, and the stationary solution of the Bloch-McConnell equation present at off-resonance frequency offset, are considered in the revised relaxation model. We demonstrate that these factors create a direct current component to the conventional relaxation model. In contrast to the previously reported dual-acquisition method, the revised relaxation model just requires one acquisition to perform quantification. The simulation, phantom, and in vivo experiments demonstrate that the proposed approach achieves superior image quality compared with the existing methods, and the revised relaxation model can perform T quantification with one acquisition instead of two.

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Paired self-compensated spin-lock preparation for improved T1 quantification

Cited by 34 publications

References 40 publications

Volumetric multicomponent T_1ρ relaxation mapping of the human liver under free breathing at 3T

Volumetric multicomponent T_1ρ relaxation mapping of the human liver under free breathing at 3T

Biexponential T_1ρ relaxation mapping of human knee cartilage in vivo at 3 T

On‐resonance and off‐resonance continuous wave constant amplitude spin‐lock and T_1ρ quantification in the presence of B₁ and B₀ inhomogeneities

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Paired self-compensated spin-lock preparation for improved T1 quantification

Cited by 34 publications

References 40 publications

Volumetric multicomponent T1ρ relaxation mapping of the human liver under free breathing at 3T

Volumetric multicomponent T1ρ relaxation mapping of the human liver under free breathing at 3T

Biexponential T1ρ relaxation mapping of human knee cartilage in vivo at 3 T

On‐resonance and off‐resonance continuous wave constant amplitude spin‐lock and T1ρ quantification in the presence of B1 and B0 inhomogeneities

Contact Info

Product

Resources

About

Volumetric multicomponent T_1ρ relaxation mapping of the human liver under free breathing at 3T

Volumetric multicomponent T_1ρ relaxation mapping of the human liver under free breathing at 3T

Biexponential T_1ρ relaxation mapping of human knee cartilage in vivo at 3 T

On‐resonance and off‐resonance continuous wave constant amplitude spin‐lock and T_1ρ quantification in the presence of B₁ and B₀ inhomogeneities