Abstract：
Magnetic resonance imaging (MRI) is the standard to quantify size and structure of lumbar muscles. Three-dimensional volumetric measures are expected to be more closely related to muscle function than two-dimensional measures such as cross-sectional area. Reliability and agreement of a standardized method should be established to enable the use of MRI to assess lumbar muscle characteristics.
This study investigates the intra- and inter-processor reliability for the quantification of (1) muscle volume and (2) fat fraction based on chemical shift MRI images using axial 3D-volume measurements of the lumbar multifidus in patients with low back pain.
Two processors manually segmented the lumbar multifidus on the MRI scans of 18 patients with low back pain using Mevislab software following a well-defined method. Fat fraction of the segmented volume was calculated. Reliability and agreement were determined using intra-class correlation coefficients (ICC), Bland-Altman plots and calculation of the standard error of measurement (SEM) and minimal detectable change (MDC).
Excellent ICCs were found for both intra-processor and inter-processor analysis of lumbar multifidus volume measurement, with slightly better results for the intra-processor reliability. The SEMs for volume were lower than 4.1 cm³. Excellent reliability and agreement were also found for fat fraction measures, with ICCs of 0.985-0.998 and SEMs below 0.946%.
The proposed method to quantify muscle volume and fat fraction of the lumbar multifidus on MRI was highly reliable, and can be used in further research on lumbar multifidus structure.
This study investigates the intra- and inter-processor reliability for the quantification of (1) muscle volume and (2) fat fraction based on chemical shift MRI images using axial 3D-volume measurements of the lumbar multifidus in patients with low back pain.
Two processors manually segmented the lumbar multifidus on the MRI scans of 18 patients with low back pain using Mevislab software following a well-defined method. Fat fraction of the segmented volume was calculated. Reliability and agreement were determined using intra-class correlation coefficients (ICC), Bland-Altman plots and calculation of the standard error of measurement (SEM) and minimal detectable change (MDC).
Excellent ICCs were found for both intra-processor and inter-processor analysis of lumbar multifidus volume measurement, with slightly better results for the intra-processor reliability. The SEMs for volume were lower than 4.1 cm³. Excellent reliability and agreement were also found for fat fraction measures, with ICCs of 0.985-0.998 and SEMs below 0.946%.
The proposed method to quantify muscle volume and fat fraction of the lumbar multifidus on MRI was highly reliable, and can be used in further research on lumbar multifidus structure.
摘要：
磁共振成像（MRI）是量化腰椎大小和结构的标准。与诸如横截面积的二维测量相比，预计三维体积测量与肌肉功能更密切相关。应建立标准化方法的可靠性和一致性，以便使用MRI评估腰肌特征。
本研究基于化学位移MRI图像，使用腰背痛患者腰椎多裂的轴向3D体积测量，研究了处理器内和处理器间对（1）肌肉体积和（2）脂肪分数的量化的可靠性。
两个处理器按照明确定义的方法，在18例腰背痛患者的MRI扫描中，使用Mevislab软件手动分割腰椎多裂。计算分段体积的脂肪分数。可靠性和一致性使用类内相关系数(ICC)确定，Bland-Altman图和测量标准误差（SEM）和最小可检测变化（MDC）的计算。
在腰椎多裂体积测量的处理器内和处理器间分析中都发现了出色的ICC，处理器内可靠性的结果略好。体积的SEM低于4.1cm²。脂肪分数测量还具有出色的可靠性和一致性，ICC为0.985-0.998，SEM低于0.946%。
提出的在MRI上量化腰椎多裂的肌肉体积和脂肪分数的方法是高度可靠的，可用于腰椎多裂结构的进一步研究。
本研究基于化学位移MRI图像，使用腰背痛患者腰椎多裂的轴向3D体积测量，研究了处理器内和处理器间对（1）肌肉体积和（2）脂肪分数的量化的可靠性。
两个处理器按照明确定义的方法，在18例腰背痛患者的MRI扫描中，使用Mevislab软件手动分割腰椎多裂。计算分段体积的脂肪分数。可靠性和一致性使用类内相关系数(ICC)确定，Bland-Altman图和测量标准误差（SEM）和最小可检测变化（MDC）的计算。
在腰椎多裂体积测量的处理器内和处理器间分析中都发现了出色的ICC，处理器内可靠性的结果略好。体积的SEM低于4.1cm²。脂肪分数测量还具有出色的可靠性和一致性，ICC为0.985-0.998，SEM低于0.946%。
提出的在MRI上量化腰椎多裂的肌肉体积和脂肪分数的方法是高度可靠的，可用于腰椎多裂结构的进一步研究。
