Longitudinal changes on liver proton density fat fraction differ between liver segments

Syväri, Jan; Junker, Daniela; Patzelt, Lisa; Kappo, Katharina Antonia; Sadat, Loubna Al; Erfanian, Sonia; Makowski, Marcus R.; Hauner, Hans; Karampinos, Dimitrios C.

doi:10.21037/qims-20-873

Cited by 7 publications

(8 citation statements)

References 26 publications

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“…Interestingly, in 1 H MRI studies, it has also been shown that the proton density fat fraction varies over the liver and that it is significantly higher in the right lobe than in the left lobe in subjects with NAFLD, obesity, or at a high risk of developing type 2 diabetes, which was speculatively associated with differences in perfusion of and/or different contributions of mesenteric versus splenic blood supply to the right and left liver lobe. [51][52][53] The observed spatial differences in 31 P metabolites across the liver will be important to take into account when assessing (the progression of) liver disease and monitoring therapy response with 31 P MRS.…”

Section: Discussionmentioning

confidence: 99%

In vivo phosphorus magnetic resonance spectroscopic imaging of the whole human liver at 7 T using a phosphorus whole‐body transmit coil and 16‐channel receive array: Repeatability and effects of principal component analysis‐based denoising

et al. 2022

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Quantitative three‐dimensional (3D) imaging of phosphorus (31P) metabolites is potentially a promising technique with which to assess the progression of liver disease and monitor therapy response. However, 31P magnetic resonance spectroscopy has a low sensitivity and commonly used 31P surface coils do not provide full coverage of the liver. This study aimed to overcome these limitations by using a 31P whole‐body transmit coil in combination with a 16‐channel 31P receive array at 7 T. Using this setup, we determined the repeatability of whole‐liver 31P magnetic resonance spectroscopic imaging (31P MRSI) in healthy subjects and assessed the effects of principal component analysis (PCA)‐based denoising on the repeatability parameters. In addition, spatial variations of 31P metabolites within the liver were analyzed. 3D 31P MRSI data of the liver were acquired with a nominal voxel size of 20 mm isotropic in 10 healthy volunteers twice on the same day. Data were reconstructed without denoising, and with PCA‐based denoising before or after channel combination. From the test–retest data, repeatability parameters for metabolite level quantification were determined for 12 31P metabolite signals. On average, 31P MR spectra from 100 ± 25 voxels in the liver were analyzed. Only voxels with contamination from skeletal muscle or the gall bladder were excluded and no voxels were discarded based on (low) signal‐to‐noise ratio (SNR). Repeatability for most quantified 31P metabolite levels in the liver was good to excellent, with an intrasubject variability below 10%. PCA‐based denoising increased the SNR ~ 3‐fold, but did not improve the repeatability for mean liver 31P metabolite quantification with the fitting constraints used. Significant spatial heterogeneity of various 31P metabolite levels within the liver was observed, with marked differences for the phosphomonoester and phosphodiester metabolites between the left and right lobe. In conclusion, using a 31P whole‐body transmit coil in combination with a 16‐channel 31P receive array at 7 T allowed 31P MRSI acquisitions with full liver coverage and good to excellent repeatability.

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Section: Discussionmentioning

confidence: 99%

In vivo phosphorus magnetic resonance spectroscopic imaging of the whole human liver at 7 T using a phosphorus whole‐body transmit coil and 16‐channel receive array: Repeatability and effects of principal component analysis‐based denoising

et al. 2022

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“…A possible way to solve this problem is to suppress the fat signal using fat saturation, inversion recovery (IR), or water excitation techniques (11)(12)(13). However, the fat signal also has diagnostic values under certain circumstances (14)(15)(16). Another idea is to separate water and fat by postprocessing the chemical shift-encoded (CSE) data (17)(18)(19).…”

Section: Introductionmentioning

confidence: 99%

“…Recently, based on the Dixon method, a variety of improved methods for water-fat separation have been developed (20)(21)(22)(23)(24). Water-fat separation methods can eliminate the effects of the fat in T1 mapping and also allow the quantification of fat, which is useful for diagnosing fatty liver disease (14)(15)(16).…”

Section: Introductionmentioning

confidence: 99%

Free-breathing simultaneous water-fat separation and T1 mapping of the whole liver (SWALI) with isotropic resolution using 3D golden-angle radial trajectory

Wang¹,

Qi²,

Wang³

et al. 2023

Quant Imaging Med Surg

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Background: Conventional liver T1 mapping techniques are typically performed under breath-holding conditions; they have limited slice coverage and often rely on multiple acquisitions. Furthermore, liver fat affects the accuracy of T1 quantification. Therefore, we aim to propose a free-breathing technique for simultaneous water-fat separation and T1 mapping of the whole liver (SWALI) in a single scan. Methods:The proposed SWALI sequence included an inversion recovery (IR) preparation pulse followed by a series of multiecho three-dimensional (3D) golden-angle radial acquisitions. For each echo time (TE), a series of images containing a mix of water and fat were reconstructed using a sliding window method. For each inversion time (TI), water and fat were separated, and then water and fat T1 estimation was conducted.The fat fraction (FF) was calculated based on the last TI image. The FF and water T1 quantification accuracy were compared with the gold standard sequences in the phantom. The in vivo feasibility was tested in 9 healthy volunteers, 2 patients with fatty liver, and 3 patients with hepatocellular carcinoma (HCC). The reproducibility was evaluated in the patients with fatty liver and in the healthy volunteers. Results:The mean FF and the mean water T1 values obtained by the SWALI sequence showed good agreements with chemical shift-encoded magnetic resonance imaging (CSE-MRI; r=0.998; P<0.001) and fat-suppressed (FS) IR-spin echo (SE; r=0.997; P<0.001) in the phantom. For the patients with fatty liver and the healthy volunteers, the SWALI sequence showed no significant difference with CSE-MRI in FF quantification (P=0.53). In T1 quantification, comparable T1 values were obtained with the SWALI sequence and modified Look-Locker inversion recovery (MOLLI; P=0.10) in healthy volunteers, while the water T1 estimated by the SWALI sequence was significantly lower than the water-fat compound T1 estimated by MOLLI (P<0.001) in patients with fatty liver. In the reproducibility study, the intraclass correlation coefficients (ICCs) for the estimated FF and water T1 were 0.997 and 0.943, respectively. Water T1 of the patients with HCC calculated using the SWALI sequence showed a significant reduction after the contrast administration (P<0.001).Conclusions: Free-breathing water-fat separation and T1 mapping of the whole liver with 2.5 mm isotropic spatial resolution were achieved simultaneously using the SWALI sequence in a 5-min scan.

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“…Previously chemical shift encoding-based fat quantification was introduced as a MR-based technique that has been applied for the assessment of muscle composition [ 8 ], since this technique allows the measurement of the MR-based proton density fat fraction (PDFF), as well as vertebral T2* values. Although MR-based mapping techniques have shown to be useful for the assessment of various body tissues, including, e.g., T2* mapping in order to assess iron depositions within the brain [ 9 ] or T2 mapping for assessment of cartilaginous tissue [ 10 ], chemical shift encoding-based fat quantification has been considered to be a promising tool for the assessment of the fatty infiltration of muscles and liver [ 11 ], as well as for the assessment of vertebral bone marrow water-fat composition [ 12 , 13 , 14 ]. In contrast to the computed tomography (CT), during the MR-based assessment of vertebral bone marrow water-fat composition, the patient is not exposed to radiation [ 15 , 16 ].…”

Section: Introductionmentioning

confidence: 99%

Associations between Bone Mineral Density and Longitudinal Changes of Vertebral Bone Marrow and Paraspinal Muscle Composition Assessed Using MR-Based Proton Density Fat Fraction and T2* Maps in Patients with and without Osteoporosis

et al. 2022

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Background: Proton-density fat fraction (PDFF) and T2* of the vertebrae, as well as the cross-sectional area (CSA) of the paraspinal musculature (PSM), have been suggested as biomarkers for bone fragility. The aim of this study was to longitudinally assess changes in PDFF, T2* and CSA of the PSM over 6 months in patients with and without osteoporosis. Methods: Opportunistic bone mineral density (BMD) measurements (BMD < 120 mg/cm3) were obtained from a CT acquired during the clinical routine work up in osteoporotic/osteopenic patients (n = 29, mean age 72.37 ± 10.12 years, 16 women). These patients were frequency-matched for age and sex to subjects with normal BMD values (n = 29). All study patients underwent 3T MR imaging at baseline and 6-month follow up, including spoiled gradient echo sequences for chemical shift encoding-based water-fat separation, from which T2* and PDFF values of the lumbar spine and the PSM were obtained. Moreover, the CSA of the PSM was assessed longitudinally. Changes in T2*, PDFF and CSA over 6 months were calculated for the vertebrae and PSM and associations with baseline BMD values were assessed. Results: The change in CSA of the PSM over 6 months was significantly lower in the osteoporotic/osteopenic group (−91.5 ± 311.7 mm2), compared to the non-osteoporotic group, in which the CSA increased (29.9 ± 164.0 mm2, p = 0.03). In a further analysis, patients with higher vertebral PDFF at baseline showed a significantly stronger increase in vertebral T2*, compared to those patients with lower vertebral PDFF at baseline (0.9 ± 1.6 ms vs. 0.0 ± 1.8 ms, p = 0.04). Moreover, patients with higher PSM PDFF at baseline showed a significantly stronger increase in vertebral T2*, compared to those patients with lower PSM PDFF at baseline (0.9 ± 2.0 ms vs. 0.0 ± 1.3 ms, p = 0.03). Conclusion: The PSM CSA decreased significantly longitudinally in patients with osteoporosis/osteopenia, compared to those without. Additionally, higher vertebral and PSM PDFF at baseline were associated with stronger changes in vertebral bone marrow T2*. Therefore, longitudinal PDFF and T2* mapping may be useful quantitative radiation-free tools for the assessment and prediction of muscle and bone health in patients with suspected osteoporosis/osteopenia.

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Longitudinal changes on liver proton density fat fraction differ between liver segments

Cited by 7 publications

References 26 publications

In vivo phosphorus magnetic resonance spectroscopic imaging of the whole human liver at 7 T using a phosphorus whole‐body transmit coil and 16‐channel receive array: Repeatability and effects of principal component analysis‐based denoising

In vivo phosphorus magnetic resonance spectroscopic imaging of the whole human liver at 7 T using a phosphorus whole‐body transmit coil and 16‐channel receive array: Repeatability and effects of principal component analysis‐based denoising

Free-breathing simultaneous water-fat separation and T1 mapping of the whole liver (SWALI) with isotropic resolution using 3D golden-angle radial trajectory

Associations between Bone Mineral Density and Longitudinal Changes of Vertebral Bone Marrow and Paraspinal Muscle Composition Assessed Using MR-Based Proton Density Fat Fraction and T2* Maps in Patients with and without Osteoporosis

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