The reliability of skeletal age determination in an Iranian sample using Greulich and Pyle method

Interdisiplinary and intraobserver reliability of the Greulich-Pyle method among Turkish children

OBJECTIVES

Greulich-Pyle (GP) is one of the most used method for bone age determination (BAD) in various orthopedic, pediatric, radiological, and forensic situations. We aimed to investigate the inter- and intra-observer reliability of the GP method between the most relevant disciplines and its applicability to the Turkish population.

METHODS

One-hundred and eighty (90 boys, 90 girls) patients with a chronological age younger than 18 (mean 9.33) were included. X-rays mixed by the blinded investigator were evaluated by two orthopedists, two radiologists, and two pediatric endocrinologists to determine skeletal age according to the GP atlas. A month later the process was repeated. As a statistical method, Paired t-test was used for comparison, an Intraclass Correlation Coefficients test was used for reliability and a 95 % confidence interval was determined. Results were classified according to Landis-Koch.

RESULTS

All results were consistent with chronological age (p<0.001), according to the investigators' evaluations compared with chronological age. At the initial evaluation, the interobserver reliability of the method was 0.999 (excellent); at the second evaluation, the interobserver reliability was 0.997 (excellent). The intra-observer reliability of the method was 'excellent' in all observers. When results were separately evaluated by gender, excellent intraobserver correlation and excellent correlation with chronological age were found among all researchers (>0.9). When X-rays were divided into three groups based on age ranges and evaluated, 'moderate' and 'good' correlations with chronological age were obtained during the peripubertal period.

CONCLUSIONS

The GP method used in skeletal age determination has excellent inter- and intra-observer reliability. During the peripubertal period, potential discrepancies in bone age assessments should be kept in mind. This method can be used safely and reproducibly by the relevant specialists.

Precision and Accuracy of Radiological Bone Age Assessment in Children among Different Ethnic Groups: A Systematic Review

AIM

The aim was to identify, evaluate, and summarize the findings of relevant individual studies on the precision and accuracy of radiological BA assessment procedures among children from different ethnic groups.

MATERIALS AND METHODS

A qualitative systematic review was carried out following the MOOSE statement and previously registered in PROSPERO (CRD42023449512). A search was performed in MEDLINE (PubMed) (n = 561), the Cochrane Library (n = 261), CINAHL (n = 103), Web of Science (WOS) (n = 181), and institutional repositories (n = 37) using MeSH and free terms combined with the Booleans "AND" and "OR". NOS and ROBINS-E were used to assess the methodological quality and the risk of bias of the included studies, respectively.

RESULTS

A total of 51 articles (n = 20,100) on radiological BA assessment procedures were precise in terms of intra-observer and inter-observer reliability for all ethnic groups. In Caucasian and Hispanic children, the Greulich-Pyle Atlas (GPA) was accurate at all ages, but in youths, Tanner-Whitehouse radius-ulna-short bones 3 (TW3-RUS) could be an alternative. In Asian and Arab subjects, GPA and Tanner-Whitehouse 3 (TW3) overestimated the BA in adolescents near adulthood. In African youths, GPA overestimated the BA while TW3 was more accurate.

CONCLUSION

GPA and TW3 radiological BA assessment procedures are both precise but their accuracy in estimating CA among children of different ethnic groups can be altered by racial bias.

Forensic age estimation in living children: how accurate is the Greulich-Pyle method in Sabah, East Malaysia?

Background

The Greulich and Pyle's Radiographic Atlas of Skeletal Development of the Hand and Wrist (GP Atlas) is the most widely used method of determining the bone age (BA) of a child. It is also a widely accepted method for forensic age determination. As there is limited local bone age data for forensic age estimation, the purpose of this study was to assess the accuracy of the GP Atlas for forensic age determination in living Sabahan children.

Method

This study recruited 182 children between the ages of 9 years to 18 years. BA estimation of the left-hand anteroposterior radiographs were performed by two experienced radiologists using the Greulich-Pyle method.

Results

The BA estimates from two radiologists had very high interobserver reliability (ICC 0.937) and a strong positive interobserver correlation (r > 0.90). The GP method, significantly and consistently underestimated chronological age (CA) by 0.7, 0.6 and 0.7 years in overall children, boys and girls respectively with minimal errors. Mean absolute error and root of mean squared error for overall children was 1.5 and 2.2 years respectively, while mean absolute percentage error was 11.6%. This underestimation was consistent across all age groups but was statistically significant only at 13-13.9 and 17-18.9 years old age groups.

Conclusion

Despite high interobserver reliability of BA estimation using the GP Atlas, this method consistently underestimates the age of the child in all children to a significant degree, for both boys and girls across all age groups, with an acceptably low level of error metrics. Our findings suggest that locally validated GP Atlas or other type of assessments (artificial intelligence or machine learning) are needed for assessment of BA to accurately predict CA, since current GP Atlas standards significantly underestimated chronological age with minimal error for children in Sabah. A larger population-based study would be necessary for establishing a validated atlas of a bone age in Malaysia.

A Study to Evaluate Accuracy and Validity of the EFAI Computer-Aided Bone Age Diagnosis System Compared With Qualified Physicians

Study Objectives

In previous research, we built a deep neural network model based on Inception-Resnet-v2 to predict bone age (EFAI-BAA). The primary objective of the study was to determine if the EFAI-BAA was substantially concordant with the qualified physicians in assessing bone ages. The secondary objective of the study was to determine if the EFAI-BAA was no different in the clinical rating (advanced, normal, or delayed) with the qualified physicians.

Method

This was a retrospective study. The left-hand X-ray images of male subjects aged 3-16 years old and female subjects aged 2-15 years old were collected from China Medical University Hospital (CMUH) and Asia University Hospital (AUH) retrospectively since the trial began until the included image amount reached 368. This was a blinded study. The qualified physicians who ran, read, and interpreted the tests were blinded to the values assessed by the other qualified physicians and the EFAI-BAA.

Results

The concordance correlation coefficient (CCC) between the EFAI-BAA (EFAI-BAA), the evaluation of bone age by physician in Kaohsiung Veterans General Hospital (KVGH), Taichung Veterans General Hospital (TVGH2), and in Taipei Tzu Chi Hospital (TZUCHI-TP) was 0.9828 (95% CI: 0.9790-0.9859, p-value = 0.6782), 0.9739 (95% CI: 0.9681-0.9786, p-value = 0.0202), and 0.9592 (95% CI: 0.9501-0.9666, p-value = 0.4855), respectively.

Conclusion

There was a consistency of bone age assessment between the EFAI-BAA and each one of the three qualified physicians (CCC = 0.9). As the significant difference in the clinical rating was only found between the EFAI-BAA and the qualified physician in TVGH2, the performance of the EFAI-BAA was considered similar to the qualified physicians.

Bone Age Assessment of Iranian Children in an Automatic Manner

Background

Bone age assessment (BAA) is a radiological process with the aim of identifying growth disorders in children. The objective of this study is to assess the bone age of Iranian children in an automatic manner.

Methods

In this context, three computer vision techniques including histogram of oriented gradients (HOG), local binary pattern (LBP), and scale-invariant feature transform (SIFT) are applied to extract appropriate features from the carpal and epiphyseal regions of interest. Two different datasets are applied here: the University of Southern California hand atlas for training this computer-aided diagnosis (CAD) system and Iranian radiographs for evaluating the performance of this system for BAA of Iranian children. In this study, the concatenation of HOG, LBP, and dense SIFT feature vectors and background subtraction are applied to improve the performance of this approach. Support vector machine (SVM) and K-nearest neighbor are used here for classification and the better results yielded by SVM.

Results

The accuracy of female radiographs is 90% and of male is 71.42%. The mean absolute error is 0.16 and 0.42 years for female and male test radiographs, respectively. Cohen's kappa coefficients are 0.86 and 0.6, P < 0.05, for female and male radiographs, respectively. The results indicate that this proposed approach is in substantial agreement with the bone age reported by the experienced radiologist.

Conclusion

This approach is easy to implement and reliable, thus qualified for CAD and automatic BAA of Iranian children.

Reproducibility and reliability analysis of the Luk Distal Radius and Ulna Classification for European patients with adolescent idiopathic scoliosis

PURPOSE

Current clinical and radiological methods of predicting a patient's growth potential are limited in terms of practicality, accuracy and known to differ in different races. This information influences optimal timing of bracing and surgical intervention in adolescent idiopathic scoliosis (AIS). The Luk classification was developed to mitigate limitations of existing tools. Few reliability studies are available and are limited to certain geographical regions with varying results. This study was performed to analyze reproducibility and reliability of the Luk Distal Radius and Ulna Classification in European patients.

METHODS

This is a radiological study of 50 randomly selected left hand and wrist radiographs of patients with AIS referred to a tertiary referral centre. They were assessed for bone maturity using the Luk Distal Radius and Ulna Classification. Assessment was performed twice by four examiners at an interval of one month. Statistical analysis was performed using the intraclass correlation (ICC) method to determine the reliabilities within and between the examiners.

RESULTS

In total, 50 radiographs (M:F = 13:37) with a mean age of 13.7 years (10 to 18) were assessed for reliability. The inter-rater ICC value was 0.918 for radius assessment and 0.939 for ulna assessment. The intra-rater ICC values for radius assessment ranged between 0.897 and 0.769 and between 0.948 and 0.786 for ulna assessment. There was near perfect correlation for both assessments.

CONCLUSION

This study provides independent evidence that the Luk Distal Radius and Ulna Classification is a reliable tool for assessment of skeletal maturity for European patients. Minimal clinical experience is required to reliably utilize it.

LEVEL OF EVIDENCE

IV.

Evaluation of Bone Age in Children: A Mini-Review

Bone age represents a common index utilized in pediatric radiology and endocrinology departments worldwide for the definition of skeletal maturity for medical and non-medical purpose. It is defined by the age expressed in years that corresponds to the level of maturation of bones. Although several bones have been studied to better define bone age, the hand and wrist X-rays are the most used images. In fact, the images obtained by hand and wrist X-ray reflect the maturity of different types of bones of the skeletal segment evaluated. This information, associated to the characterization of the shape and changes of bone components configuration, represent an important factor of the biological maturation process of a subject. Bone age may be affected by several factors, including gender, nutrition, as well as metabolic, genetic, and social factors and either acute and chronic pathologies especially hormone alteration. As well several differences can be characterized according to the numerous standardized methods developed over the past decades. Therefore, the complete characterization of the main methods and procedure available and particularly of all their advantages and disadvantages need to be known in order to properly utilized this information for all its medical and non-medical main fields of application.

Assessing the Bone Age of Children in an Automatic Manner Newborn to 18 Years Range

Bone age assessment (BAA) is a radiological process to identify the growth disorders in children. Although this is a frequent task for radiologists, it is cumbersome. The objective of this study is to assess the bone age of children from newborn to 18 years old in an automatic manner through computer vision methods including histogram of oriented gradients (HOG), local binary pattern (LBP), and scale invariant feature transform (SIFT). Here, 442 left-hand radiographs are applied from the University of Southern California (USC) hand atlas. In this experiment, for the first time, HOG-LBP-dense SIFT features with background subtraction are applied to assess the bone age of the subject group. For this purpose, features are extracted from the carpal and epiphyseal regions of interest (ROIs). The SVM and 5-fold cross-validation are used for classification. The accuracy of female radiographs is 73.88% and of the male is 68.63%. The mean absolute error is 0.5 years for both genders' radiographs. The accuracy a within 1-year range is 95.32% for female and 96.51% for male radiographs. The accuracy within a 2-year range is 100% and 99.41% for female and male radiographs, respectively. The Cohen's kappa statistical test reveals that this proposed approach, Cohen's kappa coefficients are 0.71 for female and 0.66 for male radiographs, p value < 0.05, is in substantial agreement with the bone age assessed by experienced radiologists within the USC dataset. This approach is robust and easy to implement, thus, qualified for computer-aided diagnosis (CAD). The reduced processing time and number of ROIs facilitate BAA.

Artificial intelligence in bone age assessment: accuracy and efficiency of a novel fully automated algorithm compared to the Greulich-Pyle method

Background

Bone age (BA) assessment performed by artificial intelligence (AI) is of growing interest due to improved accuracy, precision and time efficiency in daily routine. The aim of this study was to investigate the accuracy and efficiency of a novel AI software version for automated BA assessment in comparison to the Greulich-Pyle method.

Methods

Radiographs of 514 patients were analysed in this retrospective study. Total BA was assessed independently by three blinded radiologists applying the GP method and by the AI software. Overall and gender-specific BA assessment results, as well as reading times of both approaches, were compared, while the reference BA was defined by two blinded experienced paediatric radiologists in consensus by application of the Greulich-Pyle method.

Results

Mean absolute deviation (MAD) and root mean square deviation (RSMD) were significantly lower between AI-derived BA and reference BA (MAD 0.34 years, RSMD 0.38 years) than between reader-calculated BA and reference BA (MAD 0.79 years, RSMD 0.89 years; p < 0.001). The correlation between AI-derived BA and reference BA (r = 0.99) was significantly higher than between reader-calculated BA and reference BA (r = 0.90; p < 0.001). No statistical difference was found in reader agreement and correlation analyses regarding gender (p = 0.241). Mean reading times were reduced by 87% using the AI system.

Conclusions

A novel AI software enabled highly accurate automated BA assessment. It may improve efficiency in clinical routine by reducing reading times without compromising the accuracy compared with the Greulich-Pyle method.

Is the Greulich and Pyle atlas applicable to all ethnicities? A systematic review and meta-analysis

OBJECTIVE

To determine whether the Greulich and Pyle (G&P) atlas is applicable when applied to populations of different ethnicity.

METHODS

A systematic review of studies published between 1959 and 15th February 2017 identified from the Embase, MEDLINE and Cochrane databases was undertaken. Quality of the studies was assessed using the National Institute for Health and Care Excellence tool. Meta-analysis used mean differences and standard deviations as summary statistics for the difference between bone age (BA) and chronological age (CA).

RESULTS

A total of 49 studies were included of which 27 (55%) were related to Caucasian populations. Of the 49 eligible studies, 35 were appropriate for further meta-analysis. In African females, meta-analysis showed a significant mean difference between BA and CA of 0.37 years (95% CI 0.04, 0.69). In Asian males, meta-analysis showed significant differences between BA and CA of -1.08, -1.35, -1.07, -0.80 and 0.50 years for chronological ages of 6, 7, 8, 9 and 17 years, respectively. Meta-analysis showed no significant differences between BA and CA in African males, Asian females, Caucasians and Hispanics.

CONCLUSIONS

The G&P standard is imprecise and should be used with caution when applied to Asian male and African female populations, particularly when aiming to determine chronological age for forensic/legal purposes.

KEY POINTS

• In African females, bone age is significantly advanced when compared to the G&P standard. • In Asian males, bone age is significantly delayed between 6 and 9 years old inclusive and significantly advanced at 17 years old when compared to the G&P standard. • The G&P atlas should be used with caution when applied to Asian and African populations, particularly when aiming to determine chronological age for forensic/legal purposes.

Evaluation of a Computer-Aided Diagnosis System for Automated Bone Age Assessment in Comparison to the Greulich-Pyle Atlas Method: A Multireader Study

OBJECTIVE

The aim of this study was to investigate a novel version of a computer-aided diagnosis (CAD) system developed for automated bone age (BA) assessment in comparison to the Greulich and Pyle method, regarding its accuracy and the influence of carpal bones on BA assessment.

METHODS

Total BA, BA of the left distal radius, and BA of carpal bones in 305 patients were determined independently by 3 blinded radiologists and assessed by the CAD system. Pearson product-moment correlation, Bland-Altman plot, root-mean-square deviation, and further agreement analyses were computed.

RESULTS

Mean total BA and BA of the distal radius showed high correlation between both approaches (r = 0.985 and r = 0.963). There was significantly higher correlation between values of total BA and BA of the distal radius (r = 0.969) compared with values of total BA and BA of carpal bones (r = 0.923). The assessment of carpal bones showed significantly lower interreader agreement compared with measurements of the distal radius (κ = 0.79 vs κ = 0.98).

CONCLUSION

A novel version of a CAD system enables highly accurate automated BA assessment. The assessment of carpal bones revealed lower precision and interreader agreement. Therefore, methods determining BA without analyzing carpal bones may be more precise and accurate.

Bone of contention: The applicability of the Greulich-Pyle method for skeletal age assessment in South Africa

Background

The Greulich–Pyle (GP) method is one of the most commonly used radiographic techniques for skeletal age (SA) determination. The applicability of this method for populations outside of the United States has been questioned and this has been investigated in several recent studies around the world. Only limited data are available on the accuracy of the GP method for a South African population.

Objective

To determine the accuracy and reliability of the GP method in a population from KwaZulu-Natal, South Africa.

Method

A retrospective study was performed using a digital database consisting of 102 hand-wrist radiographs. The SA was estimated by two readers with different levels of experience, using the GP method. Differences between estimated SA and chronological age (CA) were analysed.

Results

Skeletal age determined with the GP method was found to significantly differ from CA. For the population as a whole, the GP method underestimated age. The greatest mean underestimation between SA and CA was 11.5 ± 17 months and 7.4 ± 13.2 months for the 10.1 to 15 year age groups in male and female patients, respectively. The method was found to have excellent inter- and intra-observer reliability.

Conclusion

The GP method generally significantly underestimates age for both genders. Overestimation is also possible with individuals as young as 16 years old found by the method to be skeletally mature. Until new SA assessment tools are developed for South Africa, use of supplementary means of determination of SA should be considered, especially in medico-legal cases.

Assessment of the 2D:4D ratio in aggression-related injuries in children attending a paediatric emergency department

BACKGROUND

The 2D:4D ratio is a sexually dimorphic trait. A lower ratio is correlated with sporting prowess, successful financial trading, risk taking behaviour, aggression, and aggression-related injuries, such as the fifth metacarpal fractures.

AIMS

We aimed to assess if the ratio correlates to skeletally immature patient aggression.

METHODS

Radiology reports were searched for the terms "5th metacarpal" or "boxer". Of 537 X-rays, 142 had fractures. The mechanism of injury was recorded in 102 patients, differentiating aggressive and non-aggressive injury groups. Bone age and chronological age were recorded.

RESULTS

A clear male preponderance for aggression was identified with only 60% of non-aggressive injuries occurring in males compared to 95% in the aggression group (p < 0.001). Patients with aggression injuries were older chronologically (14.6 vs 12.7, p < 0.001) and by bone age (14.5 vs 13.0, p < 0.001). For male patients, there was no difference in the 2D:4D ratio (p = 0.94); however, for females, the difference was significant (p = 0.04).

CONCLUSIONS

Aggression injuries occur at an older age and are more common in males. In the female cohort, there was a distinct difference in digit ratio.

A holistic approach to age estimation in refugee children

AIM

Many refugee children arriving in Australia have an inaccurately documented date of birth (DOB). A medical assessment of a child's age is often requested when there is a concern that their documented DOB is incorrect. This study's aim was to assess the accuracy a holistic age assessment tool (AAT) in estimating the age of refugee children newly settled in Australia.

METHODS

A holistic AAT that combines medical and non-medical approaches was used to estimate the ages of 60 refugee children with a known DOB. The tool used four components to assess age: an oral narrative, developmental assessment, anthropometric measures and pubertal assessment. Assessors were blinded to the true age of the child. Correlation coefficients for the actual and estimated age were calculated for the tool overall and individual components.

RESULTS

The correlation coefficient between the actual and estimated age from the AAT was very strong at 0.9802 (boys 0.9748, girls 0.9876). The oral narrative component of the tool performed best (R = 0.9603). Overall, 86.7% of age estimates were within 1 year of the true age. The range of differences was -1.43 to 3.92 years with a standard deviation of 0.77 years (9.24 months).

CONCLUSIONS

The AAT is a holistic, simple and safe instrument that can be used to estimate age in refugee children with results comparable with radiological methods currently used.

The utility of ultrasonographic bone age determination in detecting growth disturbances; a comparative study with the conventional radiographic technique

OBJECTIVE

To test whether the conventional radiographic technique in determining bone age abnormalities can be replaced by ultrasonography.

MATERIALS AND METHODS

A total of 54 Caucasian subjects up to 7 years of age with clinically suspected growth problems underwent left hand and wrist radiographic and ultrasonographic bone age estimations with the use of the Greulich-Pyle atlas. The ultrasonographic scans targeted the ossification centers in the radius and ulna distal epiphysis, carpal bones, epiphyses of the first and third metacarpals, and epiphysis of the middle phalanx, as described in previous reports. The degree of agreement between the two sets of data, as well as the accuracy of the ultrasonographic method in detecting radiographically suggested bone age abnormities, was examined.

RESULTS

The mean chronological age, radiographic bone age, and ultrasonographic bone age (all in months) were 41.96 ± 22.25, 26.68 ± 14.08, and 26.71 ± 13.50 in 28 boys and 43.62 ± 24.63, 30.12 ± 17.69, and 31.27 ± 18.06 in 26 girls, respectively. According to the Bland-Altman plot there was high agreement between the results of the two methods with only three outliers. The deviations in bone age from the chronological age taken by the two techniques had the same sign in all patients. Supposing radiography to be the method of reference, the sensitivity, specificity, positive predictive value, and negative predictive value of sonography in detecting growth abnormalities were all 100% in males and 90.9, 100, 100, and 93.8%, respectively, in females.

CONCLUSION

The conventional radiographic technique for determining bone age abnormalities could be replaced by ultrasonography.

The accuracy of estimating chronological age from Demirjian and Nolla methods in a Portuguese and Spanish sample

BACKGROUND

Age determination has great importance in many clinical decisions, being commonly used in odontopediatrics, orthodontics, pediatrics, and forensic medicine. The Nolla and Demirjian et al. methods have been used for these purposes. However, estimating chronological age by means of the dental mineralization stage is not a straightforward analysis, and it is fundamental to test the validity of these methods and their applicability to populations. In this article we intend to compare the accuracy of estimating chronological age from dental age measured with the Nolla and Demirjian methods in a Portuguese and Spanish sample, considering the variables of sex and age-group.

METHODS

The sample was composed of 821 orthopantomographs of healthy Portuguese (n = 270) and Spanish (n = 551) subjects from 4 to 34 years old. For the Nolla and Demirjian methods, seven mandibular left teeth were examined, staged according to the dental maturity scale of each method. We obtained a good index of inter-rater agreement, a good internal consistency for the teeth assessment, and a good temporal consistency.

RESULTS

Dental age was calculated for each method. The Demirjian et al. method tends to overestimate the real age of participants and the Nolla method tends to underestimate it. The accuracy of both methods varied between the sexes and age groups. Both methods were found to be more precise with males. As the age-group increases, the predictive capacities of both methods diminish. The Nolla method was more accurate than the Demirjian method in early and late childhood for both sexes. Neither method could predict chronological age in adults.

CONCLUSIONS

We can estimate chronological age for early and late childhood, through the Nolla and Demirjian methods, with the former showing greater predictive capacities than the latter. The Demirjian method tends to overestimate age and the Nolla method tends to underestimate it, leading to the importance of forming regression equations adapted to the population studied. Nolla and Demirjian formulas adapted to our sample were created as a function of sex and age-group.

Can the Greulich and Pyle method be used on French contemporary individuals?

Forensic age estimation of living individuals has become increasingly important in forensic practice with the constant increase of migration movements to developed countries. The method of Greulich and Pyle is one of the most frequently used methods for age determination. The aim of our study was to verify the reliability of this method on a French contemporary population. We retrospectively analyzed 190 frontal hand and wrist radiographs of living subjects aged between 10 and 19 years (100 males and 90 females) performed in the Radiology Department of the University Hospital of Tours. These radiographs were compared with the Greulich and Pyle atlas to determine the skeletal age (SA) and to compare it to the chronological age (CA). We calculated the coefficient of correlation and the coefficient of determination for each sex group. The SA of our subjects was also inserted in the graphs provided by Greulich and Pyle in their atlas. Intra- and inter-observer variabilities were good, demonstrating the reproducibility and repeatability of the method. The correlation coefficients were high (0.98 for males and 0.93 for females) and comparable with published data. The mean difference between CA and SA was -2.29 months for males and -6.44 months for females, showing an overestimation of CA for both sexes. No statistical difference was found between CA and SA for both male and female samples. We concluded that the method of Greulich and Pyle can be used on a contemporary French population but not without caution because of a tendency for this method to overestimate age. A fully developed hand and wrist does not allow to state that the 18th year of life is completed beyond a reasonable doubt. We recommend using it in association with other methods.