Free-breathing quantification of hepatic fat in healthy children and children with nonalcoholic fatty liver disease using a multi-echo 3-D stack-of-radial MRI technique

Armstrong, Tess; Ly, Karrie V.; Murthy, Smruthi; Ghahremani, Shahnaz; Kim, Hyun J; Calkins, Kara L.; Wu, Holden H.

doi:10.1007/s00247-018-4127-7

Cited by 42 publications

(60 citation statements)

References 66 publications

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“…In this study, the influence of respiratory motion on liver

R_{2}^{*}

quantification using free‐breathing stack‐of‐radial MRI was investigated. Previous studies showed that, with gradient delay correction, free‐breathing stack‐of‐radial imaging accurately quantified liver fat content . The results in this study revealed that stack‐of‐radial

R_{2}^{*}

quantification suffered from positive bias introduced by respiratory motion if not corrected.…”

Section: Discussionmentioning

confidence: 72%

“…Previous studies showed that, with gradient delay correction, free-breathing stack-of-radial imaging accurately quantified liver fat content. 25,26 The results in this study revealed that stack-of-radial R * 2 quantification suffered from positive bias introduced by respiratory motion if not corrected. A self-gating approach was proposed for respiratory motion compensation and accurate liver R * 2 quantification.…”

Section: Discussionmentioning

confidence: 74%

“…A free-breathing multi-echo stack-of-radial GRE imaging sequence with golden-angle ordering 28,29 was modified to support gradient delay correction, [23][24][25][26] self-gating motion compensation, 30,31 and quantification of PDFF and R * 2 . 18 A schematic block diagram of the proposed pulse sequence for data acquisition is illustrated in Figure 1.…”

Section: Pulse Sequence and Image Reconstructionmentioning

confidence: 99%

“…Gradient delay correction was performed for all radial acquisitions. [23][24][25][26] Datasets of gradient delay calibration information and 3D stack-of-radial k-space data, as well as the corresponding multichannel self-gating signals, were saved for offline processing.…”

Section: Subjects and Imaging Protocolsmentioning

confidence: 99%

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Effect of respiratory motion on free‐breathing 3D stack‐of‐radial liver relaxometry and improved quantification accuracy using self‐gating

Zhong

Armstrong

Nickel

et al. 2019

Magnetic Resonance in Med

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Purpose To develop an accurate free‐breathing 3D liver R2∗ mapping approach and to evaluate it in vivo. Methods A free‐breathing multi‐echo stack‐of‐radial sequence was applied in 5 normal subjects and 6 patients at 3 Tesla. Respiratory motion compensation was implemented using the inherent self‐gating signal. A breath‐hold Cartesian acquisition was the reference standard. Proton density fat fraction and R2∗ were measured and compared between radial and Cartesian methods using Bland‐Altman plots. The normal subject results were fitted to a linear mixed model (P < .05 considered significant). Results Free‐breathing stack‐of‐radial without self‐gating exhibited signal attenuation in echo images and artifactually elevated apparent R2∗ values. In the Bland‐Altman plots of normal subjects, compared to breath‐hold Cartesian, free‐breathing stack‐of‐radial acquisitions of 22, 30, 36, and 44 slices, had mean R2∗ differences of 27.4, 19.4, 10.9, and 14.7 s−1 with 800 radial views, and they had 18.4, 11.9, 9.7, and 27.7 s−1 with 404 views, which were reduced to 0.4, 0.9, −0.2, and −0.7 s−1 and to −1.7, −1.9, −2.1, and 0.5 s−1 with self‐gating, respectively. No substantial proton density fat fraction differences were found. The linear mixed model showed free‐breathing radial R2∗ results without self‐gating were significantly biased by 17.2 s−1 averagely (P = .002), which was eliminated with self‐gating (P = .930). Proton density fat fraction results were not different (P > .234). For patients, Bland‐Altman plots exhibited mean R2∗ differences of 14.4 and 0.1 s−1 for free‐breathing stack‐of‐radial without self‐gating and with self‐gating, respectively, but no substantial proton density fat fraction differences. Conclusion The proposed self‐gating method corrects the respiratory motion bias and enables accurate free‐breathing stack‐of‐radial quantification of liver R2∗.

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“…In this study, the influence of respiratory motion on liver

R_{2}^{*}

R_{2}^{*}

quantification suffered from positive bias introduced by respiratory motion if not corrected.…”

Section: Discussionmentioning

confidence: 72%

Section: Discussionmentioning

confidence: 74%

Section: Pulse Sequence and Image Reconstructionmentioning

confidence: 99%

Section: Subjects and Imaging Protocolsmentioning

confidence: 99%

See 2 more Smart Citations

Effect of respiratory motion on free‐breathing 3D stack‐of‐radial liver relaxometry and improved quantification accuracy using self‐gating

Zhong

Armstrong

Nickel

et al. 2019

Magnetic Resonance in Med

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“…Specifically, vendors have adopted a "stack of stars" volumetric k ‐space trajectory in which the x‐y plane of k ‐space is acquired radially, with a traditional Cartesian sampling pattern of the k ‐space z‐axis (such as StarVIBE; Siemens, Munich, Germany), yielding a high contrast and motion robust pulse sequence (Fig. ) . It should be noted that these sequences require more time than conventional T 1 /VIBE sequences (minutes instead of seconds), and in the authors' experience offer decreased motion sensitivity in the through‐plane (ie, z‐axis in axial imaging) but remain susceptible to motion degradation with in‐plane motion (ie, craniocaudal respiratory motion in coronal or sagittal imaging) …”

Section: Imaging‐specific Techniquesmentioning

confidence: 99%

Free‐breathing unsedated MRI in children: Justification and techniques

Janos

Schooler

Ngo

et al. 2019

Magnetic Resonance Imaging

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One of the more common and important challenges in the imaging of children is minimizing image degradation caused by motion. This is especially important in MRI, which is often preferable in the pediatric population due to better tissue characterization and lack of ionizing radiation. However, due to the length of time needed for most examinations, MRI is among the most sensitive to disruption by patient motion. Traditionally, deep conscious sedation or general anesthesia was the most common method of reducing motion in children who are unable or unwilling to follow direction. As the drawbacks and risks of anesthesia in children become more known and accepted, the development and optimization of means of mitigating motion and anxiety in children without the use of sedation or anesthesia becomes more urgent. In this article we describe the risks of sedation in the pediatric population and explore current methods of reducing both patient anxiety and imaging degradation from motion in the unsedated, free‐breathing child. Level of Evidence: 5 Technical Efficacy: Stage 5 J. Magn. Reson. Imaging 2019;50:365–376.

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Free‐Breathing Volumetric Liver and Proton Density Fat Fraction Quantification in Pediatric Patients Using Stack‐of‐Radial MRI With Self‐Gating Motion Compensation

Zhong

Armstrong

et al. 2020

Magnetic Resonance Imaging

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Background: Stack-of-radial multiecho gradient-echo MRI is promising for free-breathing liver R * 2 quantification and may benefit children. Purpose: To validate stack-of-radial MRI with self-gating motion compensation in phantoms, and to evaluate it in children. Study Type: Prospective. Phantoms: Four vials with different R * 2 driven by a motion stage. Subjects: Sixteen pediatric patients with suspected nonalcoholic fatty liver disease or steatohepatitis (five females, 13 ± 4 years, body mass index 29.2 ± 8.6 kg/m 2). Field Strength/Sequences: Stack-of-radial, and 2D and 3D Cartesian multiecho gradient-echo sequences at 3T. Assessment: Ungated and gated stack-of-radial proton density fat fraction (PDFF) and R * 2 maps were reconstructed without and with self-gating motion compensation. Stack-of-radial R * 2 measurements of phantoms without and with motion were validated against reference 2D Cartesian results of phantoms without motion. In subjects, free-breathing stack-ofradial and reference breath-hold 3D Cartesian were acquired. Subject inclusion for statistical analysis and region of interest placement were determined independently by two observers. Statistical Tests: Phantom results were fitted with a weighted linear model. Demographic differences between excluded and included subjects were tested by multivariate analysis of variance. PDFF and R * 2 measurements were compared using Bland-Altman analysis. Interobserver agreement was assessed by the intraclass correlation coefficient (ICC). Results: Ungated stack-of-radial R * 2 inside moving phantom vials showed a significant positive bias of 64.3 s −1 (P < 0.00001), unlike gated results (P > 0.31). Subject inclusion decisions for statistical analysis from two observers were consistent. No significant differences were found between four excluded and 12 included subjects (P = 0.14). Compared to breath-hold Cartesian, ungated and gated free-breathing stack-of-radial exhibited mean R * 2 differences of 18.5 s −1 and 3.6 s −1. Mean PDFF differences were 1.1% and 1.0% for ungated and gated measurements, respectively. Interobserver agreement was excellent (ICC for PDFF = 0.99, ICC for R * 2 = 0.90; P < 0.0003).

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Free-breathing quantification of hepatic fat in healthy children and children with nonalcoholic fatty liver disease using a multi-echo 3-D stack-of-radial MRI technique

Abstract: In this pediatric study, non-sedated free-breathing radial MRI provided accurate and repeatable hepatic PDFF measurements and improved image quality, compared to standard breath-holding MR techniques.

Cited by 42 publications

References 66 publications

Effect of respiratory motion on free‐breathing 3D stack‐of‐radial liver relaxometry and improved quantification accuracy using self‐gating

Effect of respiratory motion on free‐breathing 3D stack‐of‐radial liver relaxometry and improved quantification accuracy using self‐gating

Free‐breathing unsedated MRI in children: Justification and techniques

Free‐Breathing Volumetric Liver and Proton Density Fat Fraction Quantification in Pediatric Patients Using Stack‐of‐Radial MRI With Self‐Gating Motion Compensation

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