Department of Radiology, Hallym University Sacred Heart Hospital, Anyang-si, Gyeonggi-do, Republic of Korea.
Department of Radiology, Soonchunhyang University Seoul Hospital, Seoul, Republic of Korea.
PLoS One. 2020 Oct 21;15(10):e0241012. doi: 10.1371/journal.pone.0241012. eCollection 2020.
To evaluate the reliability of 3D image analysis and the effect of an iodine contrast agent on the computed tomography (CT) Hounsfield unit (HU) values of the proximal femur.
Fifty female patients (mean age, 61.3 years; age range, 50-79 years) who underwent both pre- and post-enhancement abdominopelvic CT scans were included in this retrospective study. Whole 3D volumes of the left proximal femur from the head to the lesser trochanter were extracted using the regional growth technique with commercial 3D software. Total volume, mean HU, and HU histogram analysis (HUHA) values of the extracted femur were calculated. HUHA distribution was classified into HUHAfat for the assumed fatty marrow (percentage of negative HU values) and HUHAdense-bone (percentage of HU values ≥ 126 HU). Reliability was assessed by calculating intra- and interobserver correlation coefficients (ICCs) and by drawing Bland-Altman plots. The effect of contrast medium administration was evaluated by the paired t-test.
All intra- and interobserver ICCs of 3D volume measurements showed excellent reproducibility (all ICCs > 0.90). On Bland-Altman analysis of two observers' 3D volume measurements, the differences in the mean total volume, HUHAfat, HUHAdense-bone, and mean HU were 2.4 cm3, 0.17%, 0.6%, and 1.9 HU, respectively. The mean difference in HU after contrast agent administration (-2.2 HU) was not significant (P = 0.27). The mean difference in HUHAfat and HUHAdense-bone after contrast agent administration were -1.1% and -2.2%, respectively, on the Bland-Altman plot. HUHAfat and HUHAdense-bone showed significant differences (P < 0.05). The 95% limits of agreement for HUHAfat, HUHAdense-bone, and mean HU were -3.6% to 1.3%, -6.5% to 2.1%, and -30.0 to 25.5 HU, respectively.
Image analysis based on 3D volume measurement of the proximal femur showed excellent reliability, with the contrast agent administration showing negligible influence on the mean HU.
评估 3D 图像分析的可靠性以及碘对比剂对股骨近端 CT 亨氏单位 (HU) 值的影响。
本回顾性研究纳入了 50 名女性患者（平均年龄 61.3 岁；年龄范围 50-79 岁），这些患者均行增强前后的腹部盆腔 CT 扫描。使用商业 3D 软件的区域生长技术提取左侧股骨近端从头到小转子的整个 3D 体积。计算提取股骨的总体积、平均 HU 和 HU 直方图分析 (HUHA) 值。HUHA 分布分为假设脂肪骨髓的 HUHAfat（负 HU 值的百分比）和 HUHA 致密骨（HU 值≥126 HU 的百分比）。通过计算观察者内和观察者间相关系数（ICC）并绘制 Bland-Altman 图来评估可靠性。通过配对 t 检验评估对比剂给药的效果。
所有观察者内和观察者间 3D 体积测量的 ICC 均显示出极好的可重复性（所有 ICC>0.90）。在两位观察者 3D 体积测量的 Bland-Altman 分析中，总容积、HUHAfat、HUHA 致密骨和平均 HU 的差异分别为 2.4 cm3、0.17%、0.6%和 1.9 HU。（P=0.27）。给予对比剂后 HU 的平均差异（-2.2 HU）无统计学意义。在 Bland-Altman 图上，给予对比剂后 HUHAfat 和 HUHAdense-bone 的平均差异分别为-1.1%和-2.2%。HUHAfat 和 HUHAdense-bone 有显著差异（P<0.05）。HUHAfat、HUHA 致密骨和平均 HU 的 95%一致性界限分别为-3.6%至 1.3%、-6.5%至 2.1%和-30.0 至 25.5 HU。
基于股骨近端 3D 体积测量的图像分析显示出极好的可靠性，给予对比剂对平均 HU 几乎没有影响。
