Fully automated bone age assessment using bag of features on hand radiograph images
Bone age assessment (BAA) considered an essential task is performed on a daily basis in hospitals all over the world with the main indication being skeletal development in growth-related abnormalities. The manual methods for BAA are time consuming and subjective, which leads to imprecise and less...
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| Main Author: | |
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| Format: | Thesis |
| Language: | English |
| Published: |
2019
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/77397/1/FK%202019%204%20UPMIR.pdf |
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| Summary: | Bone age assessment (BAA) considered an essential task is performed on a daily basis
in hospitals all over the world with the main indication being skeletal development in
growth-related abnormalities. The manual methods for BAA are time consuming and
subjective, which leads to imprecise and less accurate results. Thus, rendering the
automated BAA more favorable. The purpose for BAA is to compare the measurement
to chronological age so as to: Monitoring treatments and predict final adult height,
observe the development for the skeleton and diagnose growth disorders, and to
confirm age claims for children made by asylum seekers. Automated bone age
assessment (ABAA) systems have been developed, none of these systems have been
accepted for clinical use because there is a lack of agreement concerning the accuracy
of bone age methods which is acceptable for a clinical environment. Most of the
previously proposed methods for bone age assessment were tested on private x-ray
datasets or do not provide source code, thus their results are not reproducible or usable
as baselines. The previously proposed methods suffer from two main limitations: first,
most of the methods operate only with x-ray scans of Caucasian subjects younger than
10 years, when bones are not yet fused, thus easier than in older ages where bones
(especially, the carpal ones) overlap. Second, all of them assess bone age by extracting
features from the bones either epiphyseal-metaphyseal region of interest (EMROIs) or
carpal region of interest (CROIs) or both of them commonly adopted by the Tanner
and Whitehouse (TW) or Greulich and Pyle (GP) clinical methods, thus constraining
low-level (i.e., machine learning and computer vision) methods to use high-level (i.e.,
coming directly from human knowledge) visual descriptors. The analysis of bone age
assessment becomes more complex when the bones are nearing maturity, when most
of the bone would have merged, while some might overlap. The existing model-based
approaches in the literature often reduce the region of interest (ROI) drastically to
simplify the image analysis process, but this often leads to inaccurate and unstable
results. Any system that attempts to automate skeletal assessment in an accurate manner will need to consider the entire span of the hand radiograph. Reduced ROI
leads to inaccurate and unstable results. This semantic gap usually limits the
generalization capabilities of the devised solutions, in particular when the visual
descriptors are complex to extract as in the case of mature bones. A novel machinelearning
framework presented, aimed at overcoming these problems by learning visual
features. The proposed framework is based on speeded-up robust features (SURF)
combined with bag of features (BoF) models to quantize features computed by SURF.
Support vector machines (SVM) are used to classify the simplified feature vectors,
extracted from hand bone x-ray images. Overall 745 images were obtained, 472
images for males, 273 images for females, most of them belong to chronological ages
centered around 15 to 18 years. The proposed framework allows achieving
classification results with an average accuracy of 99%, mean absolute error 0.012 for
the 17 years and 18 years for the male gender with the SURF and BoF approach. In
the female model, the age range from 0 to 7 years are excluded, and in the male model
from 0 to 8, because of the limited amount of data that obtained, the female model
range starts from 8 years to 18 years with classification average accuracy of 82.6%.
The male model range starts from 9 years to 18 years with classification average
accuracy of 85%. |
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