Reliability of 3D image analysis and influence of contrast medium administration on measurement of Hounsfield unit values of the proximal femur
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.