Fig 1.
Flowchart of patient selection.
APCT = abdominopelvic CT.
Fig 2.
3D volume of interest (VOI) image analysis.
3D multiplanar reconstructions and volume-rendered image analysis were performed using commercial 3D software (Aquarius iNtuition v4.4.12®). The femur was selected on the volume-rendered image using the regional growth method by checking all 2D multiplanar reconstructed images. The entire bone of the proximal femur from the femoral head to the inferior margin of the lesser trochanter was extracted and analyzed. The total volume (cm3), mean HU (HU), and HU histogram analysis (HUHA) were automatically calculated. Each HUHA is shown as both a volume (cm3) and as a percentage of the VOI (%). The HUHAfat (yellow box), which reflects the percentage of HU values of zero or less in the entire VOI, represents the fatty marrow. The HUHAdense-bone (red box), which reflects the percentage of HU values of 126 or above in the entire VOI, represents dense cortical bone.
Fig 3.
Bland–Altman plots of inter-rater agreement.
Bland–Altman plots of measures of the total volume (A), the HUHAfat (B), the HUHAdense-bone (C), and the mean HU (D) show the relationships among measurements made by the two observers. Differences (y-axis) between duplicate measurements are plotted against the mean values (x-axis) of those measurements. Solid blue lines indicate mean differences. The top and bottom dashed lines correspond to the upper and lower margins of the 95% limits of agreement. At a probability of 95%, differences in normalized scores lie between the upper and lower limits of agreement (mean ± variability estimate = 1.96 standard deviations [SDs]).
Table 1.
Intraclass correlation coefficients for reliability of the 3D VOI image analysis using a single-measure, absolute-agreement, and two-way mixed effect model.
Fig 4.
Bland–Altman comparisons of data derived from pre- and postcontrast enhancement CT scans.
Bland–Altman plots for measurement of the HUHAfat (A), the HUHAdense-bone (B), and the mean HU (C) show mean differences with contrast agent administration. Differences (y-axis) are plotted against mean values (x-axis). Solid blue lines indicate mean differences. The top and bottom dashed lines are the upper and lower margins of the 95% limits of agreement. At a probability of 95%, differences in the normalized scores lie between the upper and lower limits (mean ± variability estimate = 1.96 standard deviations [SDs]).
Table 2.
Descriptions and pairwise comparisons of the mean HU, the HUHAfat, and the HUHAdense-bone before and after contrast agent administration.