In-vivo liver proton density fat fraction quantification at 0.55 T: a pilot study with comparison against 3 T MRI.

IF 2 4区医学 Q3 RADIOLOGY, NUCLEAR MEDICINE & MEDICAL IMAGING

Magnetic Resonance Materials in Physics, Biology and Medicine Pub Date : 2025-07-15 DOI:10.1007/s10334-025-01277-9

Rochelle E Wong, Bilal Tasdelen, Ye Tian, Darryl Hwang, Sophia X Cui, Liyun Yuan, Krishna S Nayak

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引用次数: 0

Abstract

Background: Proton density fat fraction (PDFF)- the ratio of unconfounded fat signal to the sum of the unconfounded fat and water signals, is a valuable quantitative imaging biomarker of metabolic associated steatotic liver disease (MASLD) widely applied in clinical practice and clinical trials. PDFF of the liver is commonly measured using 3 T MRI systems. However, low-field systems are increasingly favored due to lower cost, improved safety profile, minimized artifacts around metallic implants, and enhanced patient comfort.

Objective: In this pilot study, we used knowledge of standardized and widely used 3 T liver PDFF protocols, and adapted parameters to be appropriate for the 0.55 T MRI. We evaluate a liver fat quantification protocol at 0.55 T compared to a standard clinical 3 T protocol to measure liver fat in patients with MASLD.

Material and methods: Eight adult patients (average age 53.6 ± 13.6 years, 5 females) with ≥ 5% PDFF on 3 T MRI underwent a 0.55 T MRI PDFF protocol within 90 days. To keep the acquisition time to be within a reasonable breath hold duration and with reasonable signal-to-noise ratio (SNR), four echoes were acquired at a lower resolution and fewer number of slices at 0.55 T compared to 3 T which uses a 6-echo multi-echo Dixon volumetric interpolated breath hold examination (VIBE) protocol. PDFF quantification accuracy of the 0.55 T approach was evaluated using a commercial PDFF phantom and in vivo.

Results: In the phantom, there was excellent match (R² > 0.999) between PDFF estimated by 0.55 T MRI and ground truth. Mean in vivo 3 T MRI-PDFF was 16.5%, compared to 16.3% 0.55 T MRI-PDFF (correlation coefficient r = 0.99). The Bland-Altman analysis showed good agreement of in vivo PDFF measurements across 0.55 T and 3 T estimating a bias or mean difference of - 0.25% and the limits of agreements (LoA) of - 3.98% and 3.48%.

Discussion: Our data demonstrate that 0.55 T MRI is feasible and comparable to 3 T MRI in quantifying liver PDFF among patients with MASLD.

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体内肝脏质子密度脂肪分数量化在0.55 T：与3t MRI比较的初步研究。

背景：质子密度脂肪分数（PDFF）——无混杂脂肪信号与无混杂脂肪和水信号之和的比值，是代谢相关脂肪变性肝病（MASLD）的一种有价值的定量成像生物标志物，广泛应用于临床实践和临床试验。肝脏的PDFF通常使用3t MRI系统测量。然而，低视场系统越来越受到青睐，因为成本更低，安全性更高，金属植入物周围的伪影最小化，并且提高了患者的舒适度。目的：在这项初步研究中，我们使用了标准化和广泛使用的3t肝脏PDFF协议的知识，并调整了适合0.55 T MRI的参数。与标准临床3t方案相比，我们评估了0.55 T的肝脏脂肪量化方案，以测量MASLD患者的肝脏脂肪。材料与方法：8例3 T MRI上PDFF≥5%的成年患者（平均年龄53.6±13.6岁，5例女性）在90天内接受了0.55 T MRI PDFF方案。为了使采集时间保持在合理的屏气持续时间内，并具有合理的信噪比（SNR），与使用6回波多回波Dixon体积插值屏气检查（VIBE）协议的3 T相比，在0.55 T下以较低的分辨率和较少的切片获取了4个回声。使用商用PDFF假体和活体模型评估0.55 T方法的PDFF量化精度。结果：在幻体中，0.55 T MRI估测的PDFF与ground truth吻合良好（R2 > 0.999）。体内3 T MRI-PDFF平均为16.5%，而0.55 T MRI-PDFF为16.3%（相关系数r = 0.99）。Bland-Altman分析显示，体内PDFF测量值在0.55 T和3t之间具有良好的一致性，估计偏差或平均差为- 0.25%，一致性极限（LoA）为- 3.98%和3.48%。讨论：我们的数据表明，0.55 T MRI在量化MASLD患者肝脏PDFF方面是可行的，并且与3t MRI相当。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Magnetic Resonance Materials in Physics, Biology and Medicine 医学-核医学

CiteScore

4.60

自引率

0.00%

发文量

审稿时长

>12 weeks

期刊介绍： MAGMA is a multidisciplinary international journal devoted to the publication of articles on all aspects of magnetic resonance techniques and their applications in medicine and biology. MAGMA currently publishes research papers, reviews, letters to the editor, and commentaries, six times a year. The subject areas covered by MAGMA include: advances in materials, hardware and software in magnetic resonance technology, new developments and results in research and practical applications of magnetic resonance imaging and spectroscopy related to biology and medicine, study of animal models and intact cells using magnetic resonance, reports of clinical trials on humans and clinical validation of magnetic resonance protocols.