目的：探讨1.5T和3.0T MRI上非对称回波最小二乘估算法迭代水脂分离序列（Iterative decomposition of water and fat with echo asymmetry and least-squares estimation quantitation sequence，IDEAL-IQ）技术对腰椎椎体脂肪含量（Fat fraction，FF）定量评估的差异。材料和方法：在提供知情同意后，对21名健康志愿者在4~6 h内分别进行了腰椎1.5T和3.0T MRI的常规序列以及IDEAL-IQ序列检查，志愿者年龄21～50岁，平均（27.95±9.92）岁。在GE AW4.6工作站上分别测量不同场强下L1～L5椎体FF值，并对两组进行配对t检验分析。结果：1.5T和3.0T MRI IDEAL-IQ序列定量测量腰椎各椎体FF值不存在统计学差异，配对样本t检验分析显示，1.5T & 3.0T L1椎体（t=1.58，P=0.13），1.5T & 3.0T L2椎体（t=-1.11，P=0.28），1.5T & 3.0T L3椎体（t=0.77，P=0.45），1.5T & 3.0T L4椎体（t=0.67，P=0.51），1.5T & 3.0T L5椎体（t=0.18，P=0.86）。结论：磁共振IDEAL-IQ技术可以定量测量腰椎椎体FF值，其测量值在1.5T和3.0T场强下无差别。
Abstract
Objective: To explore the difference of proton density fat fraction(PDFF) values measured by lumbar vertebra magnetic resonance imaging(MRI) under different field strengths of 1.5T and 3.0T. Materials and Methods: This study was approved by the institutional review board. After signing informed consent, 21 healthy volunteers were scanned within 4～6 h under 1.5T and 3.0T MRI scanners, respectively. Both conventional lumbar MRI sequences and iterative decomposition of water and fat with echo asymmetry and least-squares estimation quantitation sequence(IDEAL-IQ) were tested to provide lumbar vertebra PDFF. The volunteers ranged in age from 21 to 50, with an average age of 27.95±9.92. L1~L5 lumbar vertebral sites were analyzed using IDEAL-IQ sequence, and the fat fraction(FF) values of two groups obtained from 1.5T and 3.0T GE MR scanners were compared with each other. The FF values of vertebral bone marrows were measured on AW4.6 postprocessing workstation. Paired t-test analysis between the two groups was performed. Results: The difference of the FF values was not statistically significant. Paired sample t-test analysis showed 1.5T & 3.0T L1 vertebral body(t=1.58, P=0.13), 1.5T & 3.0T L2 vertebral body(t=-1.11, P=0.28), 1.5T & 3.0T L3 vertebral body(t=0.77, P=0.45), 1.5T & 3.0T L4 vertebral body(t=0.67, P=0.51), 1.5T & 3.0 L5 vertebral body(t=0.18, P=0.86). Conclusion: Using IDEAL-IQ sequence to estimate the lumbar vertebra fat fraction is feasible. It can provide reliable marrow fat quantification.
关键词
腰椎 /
骨髓疾病 /
磁共振成像
Key words
Lumbar vertebrae /
Bone marrow diseases /
Magnetic resonance imaging
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基金
首都科技领军人才培养工程资助（Z181100006318003）。
