Abstract- The purpose of this work is to design and implement a computerized system for skeletal Bone Age Assessment (BAA) during puberty period, based on the Sauvegrain method. The system ensures accurate and robust estimation of bone age for the age group 10-13 years for girls and 12-15 years for boys. A Gaussian filter is employed for noise removal, Canny edge de- tector for edge detection, and thereafter Boundary fill algo- rithm for segmentation. From the segmented apophysis ROI of the olecranon, 8 discriminating features are extracted, which are fed in to an ID3 decision tree classifier to output the age class to which the radiograph is categorized, which is mapped onto the final bone age. The system was trained with 80 radio- graphs, 40 radiographs of girls in age group 10-13 years and 40 radiographs of boys in age group 12-15 years. After training, the system was tested on 100 radiographs (50 for girls and 50 for boys). The performance of the system was evaluated with the help of radiologist expert diagnoses. The results show that 42 out of 50 were correctly classified for girls (84%) and 40 out of 50 were correctly classified for boys (80%), with a minimal error rate of 0.66% for girls and 0.68% for boys. The system is very reliable, yielding excellent results with minimum human intervention. The performance of the system is excellent during puberty when compared to the conventional BAA systems. Keywords: Bone Age Assessment (BAA), Feature extraction, radio- graph, ID3 Classification. I. INTRODUCTION Bone age assessment is an important clinical tool in the area of pediatrics, especially in relation to endocrino- logical problems and growth disorders[1]. Based on a radiological examination of development of certain parts of the skeleton, bone age is assessed and com- pared with the chronological age. A discrepancy be- tween these two values indicates abnormalities in skel- etal development. The procedure is often used in the management and diagnosis of endocrine disorders and also serves as an indication of the therapeutic effect of treatment. It indicates whether the growth of a patient is accelerating or decreasing, based on which the pa- tient can be treated with growth hormones. BAA is uni- versally used due to its simplicity, minimal radiation exposure, and the availability of multiple ossification centers for evaluation of maturity. Many different methods are used to assess skeletal maturity. Each method makes use of different parts of the skeleton. Acheson proposed the Oxford method [2] based on the pelvis, Pyle and Hoerr [3], on the knee, Hoerr et al., on the foot [4], Tanner et al.[5], and Greulich and Pyle[6], based on the hand and wrist, and the Sauvegrain meth- od [7], based on the elbow. Of all the above, the main clinical methods for skeletal bone age estimation are the Greulich & Pyle (GP) method and the Tanner & Whitehouse (TW) method. GP is an atlas matching method while TW is a score assigning method [8]. GP method is faster and easier to use than the TW method. In GP method, a left-hand wrist radiograph is com- pared with a series of radiographs grouped in the atlas according to age and sex. The atlas pattern which su- perficially appears to resemble the clinical image is selected. TW method uses a detailed analysis of each individual bone, assigning it to one of eight classes re- flecting its developmental stage. This leads to the de- scription of each bone in terms of scores. The sum of all scores assesses the bone age. This method yields the most reliable results. Cundy et al.[9] demonstrated that the Greulich and Pyle atlas had a large inter-observer error, which is problematic in the assessment of skele- tal maturity during pubertal growth. Little et al.[10] stated that the use of the Greulich and Pyle atlas could not improve accuracy in the prediction of limb-length inequality. Hence, there comes a necessity for alterna- tive methods for skeletal BAA. Next to the above wrist x-ray methods, the elbow based methods are of much significance, especially during the spurt of puberty. The elbow is characterized by clear developmental se- quences of its ossification centers beginning at nine years of age in girls and eleven years in boys. Fusion of the elbow growth centers is complete at thirteen years in girls and fifteen years in boys. During the critical pubertal period, morphological changes of the olecra- non apophysis (shown in Fig. 1) of the elbow are very characteristic. Alain et al. [11] conducted a study to determine the accuracy of the Sauvegrain method in 2005, and proved that certain elbow growth centers showed intermediate development morphology, which failed to correspond to the scores assigned by Sauvegrain method. They also suggested intermediate scores for such cases. The purpose of this work is to propose and develop a system to estimate the bone age during puberty, based on the ossification of the olecranon apophysis in the elbow, since the interpretation of skeletal age per- formed on the olecranon apophysis alone is a simpli- fied but very practical method in clinical practice [12]. Skeletal Bone Age Assessment from elbow Radiographs 1 P.Thangam, 2 K.Thanushkodi, 3 T.V.Mahendiran, 4 P.S.Sujith 1 Assistant Professor, Sri Ramakrishna Engineering College, Coi mbatore, Tamilnadu, India. 2 Director, Akshaya College of Engineering and Technology, Coimbatore, Tamilnadu, India. 3 Assistant Professor, Coimbatore Institute of Engineering and Technology Coimbatore, Tamilnadu, India. 4 PG Scholar, Sri Ramakrishna Engineering College, Coimbatore, Tamilnadu, India. e-mail: [email protected]1 International Journal of Systems , Algorithms & Applications I I I J J J J S S S S A A A A A A A Volume 2, Issue ICTM 2011, February 2012, ISSN Online: 2277-267730 ICTM 2011|June 8-9,2011|Hyderabad|India
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Skeletal Bone Age Assessment from elbow Radiographs
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5/14/2018 Skeletal Bone Age Assessment from elbow Radiographs - slidepdf.com
Abstract - The purpose of this work is to design and implement
a computerized system for skeletal Bone Age Assessment (BAA)
during puberty period, based on the Sauvegrain method. The
system ensures accurate and robust estimation of bone age for
the age group 10-13 years for girls and 12-15 years for boys. A
Gaussian filter is employed for noise removal, Canny edge de-
tector for edge detection, and thereafter Boundary fill algo-
rithm for segmentation. From the segmented apophysis ROI of
the olecranon, 8 discriminating features are extracted, which
are fed in to an ID3 decision tree classifier to output the age
class to which the radiograph is categorized, which is mappedonto the final bone age. The system was trained with 80 radio-
graphs, 40 radiographs of girls in age group 10-13 years and 40
radiographs of boys in age group 12-15 years. After training,
the system was tested on 100 radiographs (50 for girls and 50
for boys). The performance of the system was evaluated with
the help of radiologist expert diagnoses. The results show that
42 out of 50 were correctly classified for girls (84%) and 40 out
of 50 were correctly classified for boys (80%), with a minimal
error rate of 0.66% for girls and 0.68% for boys. The system is
very reliable, yielding excellent results with minimum human
intervention. The performance of the system is excellent during
puberty when compared to the conventional BAA systems.
Keywords: Bone Age Assessment (BAA), Feature extraction, radio-graph, ID3 Classification.
I. INTRODUCTION
Bone age assessment is an important clinical tool in the
area of pediatrics, especially in relation to endocrino-
logical problems and growth disorders[1]. Based on a
radiological examination of development of certain
parts of the skeleton, bone age is assessed and com-
pared with the chronological age. A discrepancy be-
tween these two values indicates abnormalities in skel-
etal development. The procedure is often used in the
management and diagnosis of endocrine disorders and
also serves as an indication of the therapeutic effect of
treatment. It indicates whether the growth of a patient
is accelerating or decreasing, based on which the pa-
tient can be treated with growth hormones. BAA is uni-
versally used due to its simplicity, minimal radiation
exposure, and the availability of multiple ossification
centers for evaluation of maturity. Many different
methods are used to assess skeletal maturity. Each
method makes use of different parts of the skeleton.
Acheson proposed the Oxford method [2] based on the
pelvis, Pyle and Hoerr [3], on the knee, Hoerr et al., onthe foot [4], Tanner et al.[5], and Greulich and Pyle[6],
based on the hand and wrist, and the Sauvegrain meth-
od [7], based on the elbow. Of all the above, the main
clinical methods for skeletal bone age estimation are
the Greulich & Pyle (GP) method and the Tanner &
Whitehouse (TW) method. GP is an atlas matching
method while TW is a score assigning method [8]. GP
method is faster and easier to use than the TW method.
In GP method, a left-hand wrist radiograph is com-
pared with a series of radiographs grouped in the atlas
according to age and sex. The atlas pattern which su-
perficially appears to resemble the clinical image isselected. TW method uses a detailed analysis of each
individual bone, assigning it to one of eight classes re-
flecting its developmental stage. This leads to the de-
scription of each bone in terms of scores. The sum of
all scores assesses the bone age. This method yields the
most reliable results. Cundy et al.[9] demonstrated that
the Greulich and Pyle atlas had a large inter-observer
error, which is problematic in the assessment of skele-
tal maturity during pubertal growth. Little et al.[10]
stated that the use of the Greulich and Pyle atlas could
not improve accuracy in the prediction of limb-length
inequality. Hence, there comes a necessity for alterna-tive methods for skeletal BAA. Next to the above wrist
x-ray methods, the elbow based methods are of much
significance, especially during the spurt of puberty.
The elbow is characterized by clear developmental se-
quences of its ossification centers beginning at nine
years of age in girls and eleven years in boys. Fusion of
the elbow growth centers is complete at thirteen years
in girls and fifteen years in boys. During the critical
pubertal period, morphological changes of the olecra-
non apophysis (shown in Fig. 1) of the elbow are very
characteristic. Alain et al. [11] conducted a study todetermine the accuracy of the Sauvegrain method in
2005, and proved that certain elbow growth centers
showed intermediate development morphology, which
failed to correspond to the scores assigned by
Sauvegrain method. They also suggested intermediate
scores for such cases.
The purpose of this work is to propose and develop a
system to estimate the bone age during puberty, based
on the ossification of the olecranon apophysis in the
elbow, since the interpretation of skeletal age per-
formed on the olecranon apophysis alone is a simpli-fied but very practical method in clinical practice [12].
Skeletal Bone Age Assessment from elbow Radiographs
1P.Thangam, 2K.Thanushkodi, 3T.V.Mahendiran, 4P.S.Sujith1Assistant Professor, Sri Ramakrishna Engineering College, Coimbatore, Tamilnadu, India.2Director, Akshaya College of Engineering and Technology, Coimbatore, Tamilnadu, India.
3Assistant Professor, Coimbatore Institute of Engineering and Technology Coimbatore, Tamilnadu, India.4PG Scholar, Sri Ramakrishna Engineering College, Coimbatore, Tamilnadu, India.