临床环境下自由呼吸MRI期间运动不敏感翻转角调制肝脏质子密度脂肪分数和R2*映射
Motion-Insensitive Flip Angle Modulated Liver Proton Density Fat-Fraction and R2* Mapping During Free-Breathing MRI in a Clinical Setting.
作者信息
Heidenreich Julius F, Tang Jiayi, Tamada Daiki, Müller Lukas, Grunz Jan-Peter, do Vale Souza Raphael, Anagnostopoulos Alexandra, Pirasteh Ali, Reeder Scott B, Hernando Diego
机构信息
Department of Radiology, University of Wisconsin-Madison, Madison, Wisconsin, USA.
Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Germany.
出版信息
J Magn Reson Imaging. 2025 Jul 12. doi: 10.1002/jmri.70033.
BACKGROUND
Breath-held quantitative three-dimensional chemical-shift-encoded (3D-CSE)-MRI is widely used for liver fat and iron quantification but is limited in patients unable to hold breath. Motion-insensitive two-dimensional flip angle modulated (2D-FAM) acquisitions with short temporal aperture may address this limitation.
PURPOSE
To evaluate the performance of 2D-FAM-based CSE-MRI during free-breathing for quantifying proton density fat-fraction (PDFF) and R2*-based liver iron concentration (LIC).
STUDY TYPE
Retrospective single-center observational analysis.
POPULATION
230 patients (110 women [47.8%], mean age 51 ± 16 years [standard deviation, SD], range 4-85), undergoing routine clinical care between January and August 2024.
FIELD STRENGTH/SEQUENCE: 1.5-T and 3.0-T, comparison of 2D-FAM-CSE-MRI under free-breathing and breath-held 3D-CSE-MRI.
ASSESSMENT
Three radiologists evaluated image quality, apparent signal-to-noise ratio (SNR), and motion artifacts on a 5-point scale. PDFF and R2*-based LIC were measured in each liver segment from each acquisition. Agreement of PDFF and LIC between techniques was assessed, comparing body mass index (BMI) groups (< 30 and ≥ 30 kg/m). Inter-rater reliability was assessed for all analyses.
STATISTICAL TESTS
Inter-rater reliability with intra-class coefficient (ICC). Bias and limits of agreement (LoA) using Bland-Altman analysis. Linear regression assessed correlations of PDFF and LIC. Receiver operating characteristic (ROC) curves (AUC) to assess diagnostic performance. Statistical significance was set at p < 0.05 (Bonferroni-corrected p < 0.01 for patient characteristics).
RESULTS
2D-FAM demonstrated superior image quality (median rating 4 vs. 3) and fewer motion artifacts (median rating 4 vs. 3) than 3D-CSE-MRI in PDFF and R2* maps. Inter-rater reliability was good to excellent (ICC 0.77-0.92). PDFF agreement was excellent (bias: +0.32%, LoA [-1.37,2.00] for BMI < 30 kg/m; +0.66%, [-2.44,3.76] for BMI ≥ 30 kg/m). LIC agreement was high (bias: -0.02 mg/g, [-0.22,0.18]) up to a threshold of 7.0 mg/g. ROC analysis showed AUC up to 1.00 for PDFF and LIC thresholds.
DATA CONCLUSION
2D-FAM CSE-MRI enables motion-insensitive liver fat and iron quantification that can be performed during free-breathing.
EVIDENCE LEVEL
TECHNICAL EFFICACY
Stage 2.
背景
屏气定量三维化学位移编码（3D-CSE）磁共振成像广泛用于肝脏脂肪和铁含量的定量分析，但对于无法屏气的患者存在局限性。具有短时间孔径的运动不敏感二维翻转角调制（2D-FAM）采集可能解决这一局限性。
目的
评估基于2D-FAM的CSE-MRI在自由呼吸状态下定量质子密度脂肪分数（PDFF）和基于R2*的肝脏铁浓度（LIC）的性能。
研究类型
回顾性单中心观察性分析。
研究对象
2024年1月至8月期间接受常规临床护理的230例患者（110例女性[47.8%]，平均年龄51±16岁[标准差，SD]，范围4-85岁）。
场强/序列：1.5-T和3.0-T，比较自由呼吸状态下的2D-FAM-CSE-MRI和屏气3D-CSE-MRI。
评估
三名放射科医生在5分制上评估图像质量、表观信噪比（SNR）和运动伪影。从每次采集中测量每个肝段的PDFF和基于R2*的LIC。评估两种技术之间PDFF和LIC的一致性，比较体重指数（BMI）组（<30和≥30kg/m²）。对所有分析评估评分者间可靠性。
统计检验
使用组内相关系数（ICC）评估评分者间可靠性。使用Bland-Altman分析评估偏差和一致性界限（LoA）。线性回归评估PDFF和LIC的相关性。绘制受试者工作特征（ROC）曲线（AUC）以评估诊断性能。统计学显著性设定为p<0.05（患者特征的Bonferroni校正p<0.01）。
结果
在PDFF和R2*图中，2D-FAM显示出比3D-CSE-MRI更好的图像质量（中位数评分4比3）和更少的运动伪影（中位数评分4比3）。评分者间可靠性良好至优秀（ICC 0.77-0.92）。PDFF一致性极佳（偏差：BMI<30kg/m²时为+0.32%，LoA为[-1.37,2.00]；BMI≥30kg/m²时为+0.66%，[-2.44,3.76]）。LIC一致性较高（偏差：-0.02mg/g，[-0.22,0.18]），直至阈值7.0mg/g。ROC分析显示PDFF和LIC阈值的AUC高达1.00。
数据结论
2D-FAM CSE-MRI能够在自由呼吸状态下进行运动不敏感的肝脏脂肪和铁含量定量分析。
证据水平
2级。
技术效能
2级。
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