背景:该研究的目的是使用机会性低剂量胸部CT研究成骨不全症(OI)儿童的肌肉差异,并比较不同的儿童肌肉分割方法。
方法:这项单中心回顾性研究纳入了在COVID大流行期间接受机会性低剂量胸部CT检查的OI患儿和对照组。从CT图像来看,使用两种方法在T4中期和T10中期水平测量躯干肌肉的肌肉大小(横截面积)和密度(平均Hounsfield单位[HU]),固定阈值和高斯混合模型。Bland-Altman方法也用于计算两种方法之间的一致性强度。用Studentt检验分析OI和对照之间的肌肉结果的比较。
结果:20名OI儿童(平均年龄,9.1±3.3年,招募了15名男性)和40名年龄和性别匹配的对照。两种方法之间的平均差异很好。OI患儿的T4和T10肌肉密度低于固定阈值测量的对照组(41.2HUvs.48.0HU,p<0.01;37.3HUvs.45.9HU,p<0.01)。然而,患有OI的儿童T4肌肉尺寸较低,T4肌肉密度,高斯混合模型测得的T10肌肉大小和T10肌肉密度比对照(110.9vs.127.2cm2,p=0.03;44.6HUvs.51.3HU,p<0.01;72.6vs.88.0cm2,p=0.01;41.6HUvs.50.3HU,p分别<0.01)。
结论:患有OI的儿童躯干肌肉密度较低,表明OI也可能损害肌肉质量。此外,固定阈值可能不适合儿童肌肉分割。
BACKGROUND: The aim of the study was to investigate the muscle differences in children with osteogenesis imperfecta (OI) using opportunistic low-dose chest CT and to compare different methods for the segmentation of muscle in children.
METHODS: This single center retrospective study enrolled children with OI and controls undergoing opportunistic low-dose chest CT obtained during the COVID pandemic. From the CT images, muscle size (cross-sectional area) and density (mean Hounsfield Units [HU]) of the trunk
muscles were measured at the mid-T4 and the mid-T10 level using two methods, the fixed thresholds and the Gaussian mixture model. The Bland-Altman method was also used to compute the strength of agreement between two methods. Comparison of muscle results between OI and controls were analyzed with Student t tests.
RESULTS: 20 children with OI (mean age, 9.1 ± 3.3 years, 15 males) and 40 age- and sex-matched controls were enrolled. Mean differences between two methods were good. Children with OI had lower T4 and T10 muscle density than controls measured by the fixed thresholds (41.2 HU vs. 48.0 HU, p < 0.01; 37.3 HU vs. 45.9 HU, p < 0.01). However, children with OI had lower T4 muscle size, T4 muscle density, T10 muscle size and T10 muscle density than controls measured by the Gaussian mixture model (110.9 vs. 127.2 cm2, p = 0.03; 44.6 HU vs. 51.3 HU, p < 0.01; 72.6 vs. 88.0 cm2, p = 0.01; 41.6 HU vs. 50.3 HU, p < 0.01, respectively).
CONCLUSIONS: Children with OI had lower trunk muscle density indicating that OI might also impair muscle quality. Moreover, the fixed thresholds may not be suitable for segmentation of muscle in children.