System Performance

Image base

Left hand wrist radiographs selected from a normal population are organized into four groups: African American male and female and Caucasian male and female.

• for pre-pubertal children (0 to 9-year-old) 5 images for each year
• for children during puberty (10 to 18-year-old) 10 images for each year

135 images per group and a total of 540 images. The images are acquired at the Childrens Hospital Los Angeles/USC.

Image processing errors

The system has been able to process more than 90% of tested hand radiographs. 7% of fails occurs at image preprocessing stage:

• 1% low contrast,many artifacts disables the hand location
• 6% fingers attached to each other cannot be separated in binary image

Other errors (3%) are related to region extraction or processing. As usually such errors occur only for one or two out of six regions, the system still can evaluate the bone age (due to redundant information from multiple ROI), however the result may be less reliable.The operator can inspect it by looking at Fuzzy Bone Age:Details window.

Evaluation of Bone Age

The plots show the bone age assessed by CABAA system vs. chronological age for images from the reference image base. Red line marks the ideal corespondence. For girls in the considered ROIs the epiphyseal fusion is completed at 15-16 years of age and the system cannot give an accurate bone age assessment afterwards.

Gender	Boys	Girls
Bone Age
Average difference [years]	0.89	0.75 (up to 15 years of age) 1.05 (all)