在不同场强和扫描间隔下质子密度脂肪分数测量的准确性和精密度：一项体模和人体研究。
Accuracy and precision of proton density fat fraction measurement across field strengths and scan intervals: A phantom and human study.
机构信息
Department of Radiology, Ajou University School of Medicine, Ajou University Hospital, Suwon, South Korea.
Department of Gastroenterology, Ajou University School of Medicine, Ajou University Hospital, Suwon, South Korea.
出版信息
J Magn Reson Imaging. 2019 Jul;50(1):305-314. doi: 10.1002/jmri.26575. Epub 2018 Nov 14.
BACKGROUND
Complex-based chemical shift imaging-based magnetic resonance imaging (CSE-MRI) is emerging as a preferred method for noninvasively quantifying proton density fat fraction (PDFF), a promising quantitative imaging biomarker (QIB) for longitudinal hepatic steatosis measurement.
PURPOSE
To determine linearity, bias, repeatability, and reproducibility of the PDFF measurement using CSE-MRI (CSE-PDFF) across scan intervals, MR field strengths, and readers in phantom and nonalcoholic fatty liver disease (NAFLD) patients.
STUDY TYPE
Institutional Review Board (IRB)-approved prospective.
SUBJECTS
Fat-water phantom and 20 adult patients.
FIELD STRENGTH/SEQUENCE: 1.5 T and 3.0 T MR systems and a commercially available CSE-MRI sequence (IDEAL-IQ).
ASSESSMENT
Two independent readers measured CSE-PDFF of fat-water phantom and NAFLD patients across two field strengths and scan intervals (same-day and 2-week) each and in a combination of both. MR spectroscopy-based PDFF (MRS-PDFF) was used as the reference standard for phantom PDFF.
STATISTICAL TESTS
Linearity and bias of measurement were evaluated by linear regression analysis and Bland-Altman plots, respectively. Repeatability and reproducibility were assessed by coefficient of variance and repeatability / reproducibility coefficients (RC). The intraclass correlation coefficient was used to validate intra- and interobserver agreements.
RESULTS
CSE-PDFF showed high linearity and small bias (-0.6-0.4 PDFF%) with 95% limits of agreement within ±2.9 PDFF% across field strengths, 2-week interscan period, and readers in the clinical scans. CSE-PDFF was highly repeatable and reproducible both in phantom and clinical scans, with the largest observed RC across field strengths and 2-week interscan period being 3 PDFF%.
DATA CONCLUSION
CSE-PDFF is a robust QIB with high linearity, small bias, and excellent repeatability/reproducibility. A change of more than 3 PDFF% across field strengths within 2 weeks of scan interval likely reflects a true change, which is well within the clinically acceptable range.
LEVEL OF EVIDENCE
3 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;50:305-314.
背景
基于复杂的化学位移成像的磁共振成像（CSE-MRI）正在成为一种非侵入性定量质子密度脂肪分数（PDFF）的首选方法，PDFF 是一种有前途的用于肝脂肪变性纵向测量的定量成像生物标志物（QIB）。
目的
在体模和非酒精性脂肪性肝病（NAFLD）患者中，确定 CSE-MRI（CSE-PDFF）在扫描间隔、MR 场强和读者之间的 PDFF 测量的线性、偏差、重复性和再现性。
研究类型
机构审查委员会（IRB）批准的前瞻性研究。
受试者
脂肪-水体模和 20 名成年患者。
场强/序列：1.5T 和 3.0T MR 系统和一种商业上可用的 CSE-MRI 序列（IDEAL-IQ）。
评估
两位独立的读者在两个场强和扫描间隔（当天和 2 周）以及两者的组合中测量了脂肪-水体模和 NAFLD 患者的 CSE-PDFF，并使用基于磁共振波谱的 PDFF（MRS-PDFF）作为体模 PDFF 的参考标准。
统计检验
通过线性回归分析和 Bland-Altman 图分别评估测量的线性和偏差。通过方差系数和重复性/再现性系数（RC）评估重复性和再现性。使用组内相关系数验证观察者内和观察者间的一致性。
结果
在临床扫描中，CSE-PDFF 在整个场强、2 周的扫描间隔和读者中均表现出高度的线性和较小的偏差（-0.6-0.4 PDFF%），95%一致性区间在±2.9 PDFF%范围内。CSE-PDFF 在体模和临床扫描中均具有高度的重复性和再现性，在整个场强和 2 周的扫描间隔中，最大的观察到 RC 为 3 PDFF%。
数据结论
CSE-PDFF 是一种具有高线性、小偏差和优异重复性/再现性的强大 QIB。在 2 周的扫描间隔内，场强变化超过 3 PDFF%可能反映了真实的变化，这在临床可接受的范围内。
证据水平
3 技术功效：第 2 阶段 J. Magn. Reson. Imaging 2019;50:305-314.
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