MR elastography in patients with suspected diffuse liver disease at 1.5T: Intraindividual comparison of gradient-recalled echo versus spin-echo echo-planar imaging sequences and investigation of potential confounding factors

Plaikner, Michaela; Kremser, Christian; Zoller, Heinz; Kannengießer, Stephan; Henninger, Benjamin

doi:10.1016/j.ejrad.2021.109898

Cited by 8 publications

(11 citation statements)

References 28 publications

(38 reference statements)

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“…Reduced spatial resolution used in SE‐EPI MRE has implications on the accuracy of computation of liver stiffness 8,16–18 . Correspondingly, it has been demonstrated that spatial resolution of 9–10 pixels per displacement wavelength is required for accurate stiffness estimation 18 .…”

Section: Discussionmentioning

confidence: 99%

“…Correspondingly, it has been demonstrated that spatial resolution of 9–10 pixels per displacement wavelength is required for accurate stiffness estimation 18 . Proportional bias can be observed between the liver stiffness measurements with SE‐EPI and GRE MRE sequences in previous studies 8,16 . Thus, it is important that the acceleration of MRE acquisitions is achieved through strategies that maintain a minimum spatial encoding resolution of 2 mm in at least one spatial encoding direction over a wide range of body habitus.…”

Section: Discussionmentioning

confidence: 99%

“…4 Reduced spatial resolution used in SE-EPI MRE has implications on the accuracy of computation of liver stiffness. 8,[16][17][18] Correspondingly, it has been demonstrated that spatial resolution of 9-10 pixels per displacement wavelength is required for accurate stiffness estimation. 18 Proportional bias can be observed between the liver stiffness measurements with SE-EPI and GRE MRE sequences in previous studies.…”

Section: Discussionmentioning

confidence: 99%

“…Each strategy to reduce or eliminate breath holds involves tradeoffs. In the case of SE‐EPI MRE, the acquired in‐plane spatial resolution is commonly reduced by a factor of 3 compared to standard of care GRE MRE 8,13,16 . This reduction in spatial resolution affects the quality of the measured displacement maps.…”

mentioning

confidence: 99%

“…In the case of SE-EPI MRE, the acquired in-plane spatial resolution is commonly reduced by a factor of 3 compared to standard of care GRE MRE. 8,13,16 This reduction in spatial resolution affects the quality of the measured displacement maps. Specifically, it has been demonstrated that the wavelength-to-pixel ratio regulates the impact of noise and discretization on the computation of stiffness from the displacement map.…”

mentioning

confidence: 99%

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Performance of C‐SENSE Accelerated Rapid Liver Shear Stiffness Measurement Using Displacement Wave Polarity‐Inversion Motion Encoding: An Evaluation Study

Pednekar

Gandhi

Wang

et al. 2022

Magnetic Resonance Imaging

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BackgroundLiver shear stiffness measurement using magnetic resonance elastography (MRE) aids in the noninvasive diagnosis and staging of liver fibrosis. Inadequate breath‐holds can lead to inaccurate stiffness estimation and/or failed MRE exams.PurposeTo prospectively evaluate the performance of compressed sensitivity encoding (C‐SENSE) accelerated rapid MRE measurement of liver shear stiffness using displacement wave polarity‐inversion motion encoding.Study TypeRetrospective.SubjectsEleven with liver disease and 10 asymptomatic subjects.Field Strength/Sequence1.5 T; gradient‐recalled‐echo (GRE) MRE.AssessmentAll participants underwent: 1) two‐dimensional (2D) GRE MRE with inflow saturation using SENSE acceleration factor (R) of 2 (standard of care [SC]); 2) 2D rapid MRE with (RwS); and 3) without (RnS) inflow saturation using C‐SENSE R = 3; and 4) spatial three‐dimensional (3D) rapid MRE with inflow saturation (R3D) using C‐SENSE R = 4; with nominally identical spatial resolution and coverage. Image analyst (D.G., 2 years of experience) drew identical and maximal regions of interest (ROIs) in right hepatic lobe.Statistical TestsLinear regression, intra‐class correlation coefficients (ICC), Bland–Altman analyses, and the Wilcoxon signed‐rank test were used to assess consistency and agreement of liver stiffness measurements for manually drawn identical and maximal ROIs.ResultsIn 21 participants (37 ± 14 years) with liver stiffness (2.3 ± 0.7 kPa), body mass index (BMI 27 ± 7 kg/m2), proton density fat fraction (PDFF 9 ± 9%), and T2* (27 ± 4 msec); rapid MRE sequences showed excellent agreement (ICC > 0.95) with SC MRE and no correlation (r2 < 0.1) of the differences (mean difference <0.2 kPa, <6%; limits of agreement <0.4 kPa, <16%) with BMI, PDFF, and T2*. Breath‐hold times were: 14 seconds (SC), 5 seconds (RnS), 7 seconds (RwS) per slice, and 16 seconds for the R3D acquisition.Data ConclusionsC‐SENSE accelerated GRE MRE sequences, using displacement wave polarity‐inversion motion encoding, produce equivalent measurements of liver stiffness and have potential clinical benefit in patients with limited breath‐holding capacity.Level of Evidence1Technical EfficacyStage 1

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Performance of C‐SENSE Accelerated Rapid Liver Shear Stiffness Measurement Using Displacement Wave Polarity‐Inversion Motion Encoding: An Evaluation Study

Pednekar

Gandhi

Wang

et al. 2022

Magnetic Resonance Imaging

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Phase‐regularized and displacement‐regularized compressed sensing for fast magnetic resonance elastography

2023

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Liver magnetic resonance elastography (MRE) is a noninvasive stiffness measurement technique that captures the tissue displacement in the phase of the signal. To limit the scanning time to a single breath‐hold, liver MRE usually involves advanced readout techniques such as simultaneous multislice (SMS) or multishot methods. Furthermore, all these readout techniques require additional in‐plane acceleration using either parallel imaging capabilities, such as sensitivity encoding (SENSE), or k‐space undersampling, such as compressed sensing (CS). However, these methods apply a single regularization function on the complex image. This study aims to design and evaluate methods that use separate regularization on the magnitude and phase of MRE to exploit their distinct spatiotemporal characteristics. Specifically, we introduce two compressed sensing methods. The first method, termed phase‐regularized compressed sensing (PRCS), applies a two‐dimensional total variation (TV) prior to the magnitude and two‐dimensional wavelet regularization to the phase. The second method, termed displacement‐regularized compressed sensing (DRCS), exploits the spatiotemporal redundancy using 3D total variation on the magnitude. Additionally, DRCS includes a displacement fitting function to apply wavelet regularization to the displacement phasor. Both DRCS and PRCS were evaluated with different levels of compression factors in three datasets: an in silico abdomen dataset, an in vitro tissue‐mimicking phantom, and an in vivo liver dataset. The reconstructed images were compared with the full sampled reconstruction, zero‐filling reconstruction, wavelet‐regularized compressed sensing, and a low rank plus sparse reconstruction. The metrics used for quantitative evaluation were the structural similarity index (SSIM) of magnitude (M‐SSIM), displacement (D‐SSIM), and shear modulus (S‐SSIM), and mean shear modulus. Results from highly undersampled in silico and in vitro datasets demonstrate that the DRCS method provides higher reconstruction quality than the conventional compressed sensing method for a wide range of stiffness values. Notably, DRCS provides 24% and 22% increase in D‐SSIM compared with CS for the in silico and in vitro datasets, respectively. Comparison with liver stiffness measured from full sampled data and highly undersampled data (CR=4) demonstrates that the DRCS method provided the strongest correlation ( R2=0.95), second‐lowest mean bias (−0.18 kPa, lowest for CS with −0.16 kPa), and lowest coefficient of variation (CV=3.6%). Our results demonstrate the potential of using DRCS to improve the reconstruction quality of accelerated MRE.

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Feasibility and performance of spin-echo EPI MR elastography at 3 Tesla for staging hepatic fibrosis in the presence of hepatic iron overload

Sgier,

Stocker,

Jüngst

et al. 2024

Abdom Radiol

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Purpose To assess the feasibility and performance of MR elastography (MRE) for quantifying liver fibrosis in patients with and without hepatic iron overload. Methods This retrospective single-center study analyzed 139 patients who underwent liver MRI at 3 Tesla including MRE (2D spin-echo EPI sequence) and R2* mapping for liver iron content (LIC) estimation. MRE feasibility and diagnostic performance between patients with normal and elevated LIC were compared. Results Patients with elevated LIC (21%) had significantly higher MRE failure rates (24.1% vs. 3.6%, p < 0.001) compared to patients with normal LIC (79%). For those with only insignificant to mild iron overload (LIC < 5.4 mg/g; 17%), MRE failure rate did not differ significantly from patients without iron overload (8.3% vs. 3.6%, p = 0.315). R2* predicted MRE failure with fair accuracy at a threshold of R2* ≥ 269 s−1 (LIC of approximately 4.6 mg/g). MRE showed good diagnostic performance for detecting significant (≥ F2) and severe fibrosis (≥ F3) in patients without (AUC 0.835 and 0.900) and with iron overload (AUC 0.818 and 0.889) without significant difference between the cohorts (p = 0.884 and p = 0.913). For detecting cirrhosis MRE showed an excellent diagnostic performance in both groups (AUC 0.944 and 1.000, p = 0.009). Conclusion Spin-echo EPI MRE at 3 Tesla is feasible in patients with mild iron overload with good to excellent performance for detecting hepatic fibrosis with a failure rate comparable to patients without iron overload.

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MR elastography in patients with suspected diffuse liver disease at 1.5T: Intraindividual comparison of gradient-recalled echo versus spin-echo echo-planar imaging sequences and investigation of potential confounding factors

Abstract: Intraindividual comparison of gradient-recalled echo versus spin-echo echo-planar imaging sequences and investigation of potential confounding factors

Cited by 8 publications

References 28 publications

Performance of C‐SENSE Accelerated Rapid Liver Shear Stiffness Measurement Using Displacement Wave Polarity‐Inversion Motion Encoding: An Evaluation Study

Performance of C‐SENSE Accelerated Rapid Liver Shear Stiffness Measurement Using Displacement Wave Polarity‐Inversion Motion Encoding: An Evaluation Study

Phase‐regularized and displacement‐regularized compressed sensing for fast magnetic resonance elastography

Feasibility and performance of spin-echo EPI MR elastography at 3 Tesla for staging hepatic fibrosis in the presence of hepatic iron overload

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