Accuracy of Multi-echo Dixon Sequence in Quantification of Hepatic Steatosis

Two-point Dixon and six-point Dixon magnetic resonance techniques in the detection, quantification and grading of hepatic steatosis

BACKGROUND

Hepatic steatosis is a very common problem worldwide.

AIM

To assess the performance of two- and six-point Dixon magnetic resonance (MR) techniques in the detection, quantification and grading of hepatic steatosis.

METHODS

A single-center retrospective study was performed in 62 patients with suspected parenchymal liver disease. MR sequences included two-point Dixon, six-point Dixon, MR spectroscopy (MRS) and MR elastography. Fat fraction (FF) estimates on the Dixon techniques were compared to the MRS-proton density FF (PDFF). Statistical tests used included Pearson's correlation and receiver operating characteristic.

RESULTS

FF estimates on the Dixon techniques showed excellent correlation (≥ 0.95) with MRS-PDFF, and excellent accuracy [area under the receiver operating characteristic (AUROC) ≥ 0.95] in: (1) Detecting steatosis; and (2) Grading severe steatosis, (P < 0.001). In iron overload, two-point Dixon was not evaluable due to confounding T2* effects. FF estimates on six-point Dixon vs MRS-PDFF showed a moderate correlation (0.82) in iron overload vs an excellent correlation (0.97) without iron overload, (P < 0.03). The accuracy of six-point Dixon in grading mild steatosis improved (AUROC: 0.59 to 0.99) when iron overload cases were excluded. The excellent correlation (> 0.9) between the Dixon techniques vs MRS-PDFF did not change in the presence of liver fibrosis (P < 0.01).

CONCLUSION

Dixon techniques performed satisfactorily for the evaluation of hepatic steatosis but with exceptions.

Advances in application of novel magnetic resonance imaging technologies in liver disease diagnosis

Liver disease is a major health concern globally, with high morbidity and mor-tality rates. Precise diagnosis and assessment are vital for guiding treatment approaches, predicting outcomes, and improving patient prognosis. Magnetic resonance imaging (MRI) is a non-invasive diagnostic technique that has been widely used for detecting liver disease. Recent advancements in MRI technology, such as diffusion weighted imaging, intravoxel incoherent motion, magnetic resonance elastography, chemical exchange saturation transfer, magnetic resonance spectroscopy, hyperpolarized MR, contrast-enhanced MRI, and ra-diomics, have significantly improved the accuracy and effectiveness of liver disease diagnosis. This review aims to discuss the progress in new MRI technologies for liver diagnosis. By summarizing current research findings, we aim to provide a comprehensive reference for researchers and clinicians to optimize the use of MRI in liver disease diagnosis and improve patient prognosis.

Evaluation of a Whole-Liver Dixon-Based MRI Approach for Quantification of Liver Fat in Patients with Type 2 Diabetes Treated with Two Isocaloric Different Diets

Dixon-based methods for the detection of fatty liver have the advantage of being non-invasive, easy to perform and analyze, and to provide a whole-liver coverage during the acquisition. The aim of the study was to assess the feasibility of a whole-liver Dixon-based approach for liver fat quantification in type 2 diabetes (T2D) patients who underwent two different isocaloric dietary treatments: a diet rich in monosaturated fatty acids (MUFA) and a multifactorial diet. Thirty-nine T2D patients were randomly assigned to MUFA diet (n = 21) and multifactorial diet (n = 18). The mean values of the proton density fat fraction (PDFF) over the whole liver and over the ROI corresponding to that chosen for MRS were compared to MRS-PDFF using Spearman’s correlation (ρ). Before–after changes in percentage of liver volume corresponding to MRI-PDFF above thresholds associated with hepatic steatosis (LV%TH, with TH = 5.56%, 7.97% and 8.8%) were considered to assess the proposed approach and compared between diets using Wilcoxon rank-sum test. Statistical significance set at p < 0.05. A strong linear relationship was found between MRS-PDFF and MRI-PDFFs (ρ = 0.85, p < 0.0001). Changes in LV%TH% were significantly higher (p < 0.05) in the multifactorial diet than in MUFA diet (25% vs. 9%, 35% vs. 12%, and 38% vs. 13% decrease, respectively, for TH = 5.56%, 7.97%, and 8.8%) and this was reproducible compared to results obtained using the standard liver fat analysis. A volumetric approach based on Dixon method could be an effective, non-invasive technique that could be used for the quantitative analysis of hepatic steatosis in T2D patients.

Quantification of bone marrow edema in rheumatoid arthritis by using high-speed T2-corrected multiecho acquisition of 1H magnetic resonance spectroscopy: a feasibility study

OBJECTIVE

To determine whether high-speed T2-corrected multiecho (HISTO) sequences can quantify bone marrow edema (BME) in the capitate bone in rheumatoid arthritis (RA), and whether the HISTO fat fraction (FF) reflects therapeutic effectiveness.

METHODS

In this prospective study, 25 RA patients (19 women; average age, 45.08 ± 13.48 years) underwent 3.0-T MRI with HISTO at the baseline and after 4, 8, and 12 weeks of treatment. Rheumatoid factor (RF), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), platelet (PLT) count, and 28-joint Disease Activity Score using ESR (DAS28-ESR) were recorded on the day of each MRI examination by a rheumatologist blinded to the MRI findings. In addition, 21 healthy subjects (15 women; age, 49.17 ± 6.56 years) underwent only the HISTO sequence at a single time point.

RESULTS

HISTO FF values were significantly higher in the control group (74.5% ± 3.1%; range, 68.6-79.3%) than in the patient group (55.8% ± 17.7%; range, 15.6-79.0%) at the baseline (independent-samples t-test: t = 5.257, P = 0.000). The changes in HISTO FF and DAS28-ESR showed moderate negative correlations with each other at 4, 8, and 12 weeks, and all of them were statistically significant (P < 0.05). As the HISTO FF increased, the DAS28-ESR decreased.

CONCLUSION

The HISTO sequence can measure the bone marrow FF of the wrist joint bones in RA patients. The HISTO FF value increased as the DAS28-ESR decreased. The HISTO sequence may help quantify BME in RA and help monitor the effectiveness of RA treatment. Key Points •The HISTO sequence could measure the bone marrow FF of the wrist joint bones. •FF value increased as the DAS28-ESR decreased in RA patients. •The HISTO sequence can monitor the therapeutic effect of RA.