Predictive Modelling of Bone Age through Classification and Regression of Bone Shapes

Bone age assessment is a task performed daily in hospitals worldwide. This involves a clinician estimating the age of a patient from a radiograph of the non-dominant hand. Our approach to automated bone age assessment is to modularise the algorithm into the following three stages: segment and verify hand outline; segment and verify bones; use the bone outlines to construct models of age. In this paper we address the final question: given outlines of bones, can we learn how to predict the bone age of the patient? We examine two alternative approaches. Firstly, we attempt to train classifiers on individual bones to predict the bone stage categories commonly used in bone ageing. Secondly, we construct regression models to directly predict patient age. We demonstrate that models built on summary features of the bone outline perform better than those built using the one dimensional representation of the outline, and also do at least as well as other automated systems. We show that models constructed on just three bones are as accurate at predicting age as expert human assessors using the standard technique. We also demonstrate the utility of the model by quantifying the importance of ethnicity and sex on age development. Our conclusion is that the feature based system of separating the image processing from the age modelling is the best approach for automated bone ageing, since it offers flexibility and transparency and produces accurate estimate

Pediatric Bone Age Assessment Using Deep Convolutional Neural Networks

Skeletal bone age assessment is a common clinical practice to diagnose endocrine and metabolic disorders in child development. In this paper, we describe a fully automated deep learning approach to the problem of bone age assessment using data from Pediatric Bone Age Challenge organized by RSNA 2017. The dataset for this competition is consisted of 12.6k radiological images of left hand labeled by the bone age and sex of patients. Our approach utilizes several deep learning architectures: U-Net, ResNet-50, and custom VGG-style neural networks trained end-to-end. We use images of whole hands as well as specific parts of a hand for both training and inference. This approach allows us to measure importance of specific hand bones for the automated bone age analysis. We further evaluate performance of the method in the context of skeletal development stages. Our approach outperforms other common methods for bone age assessment.Comment: 14 pages, 9 figure

Brain Differences in the Prefrontal Cortex, Amygdala, and Hippocampus in Youth with Congenital Adrenal Hyperplasia

Context: Classical Congenital Adrenal Hyperplasia (CAH) due to 21-hydroxylase deficiency results in hormone imbalances present both prenatally and postnatally that may impact the developing brain. Objective: To characterize gray matter morphology in the prefrontal cortex and subregion volumes of the amygdala and hippocampus in youth with CAH, compared to controls. Design: A cross-sectional study of 27 CAH youth (16 female; 12.6 ± 3.4 year) and 35 typically developing, healthy controls (20 female; 13.0 ± 2.8 year) with 3-T magnetic resonance imaging scans. Brain volumes of interest included bilateral prefrontal cortex, and nine amygdala and six hippocampal subregions. Between-subject effects of group (CAH vs control) and sex, and their interaction (group-by-sex) on brain volumes were studied, while controlling for intracranial volume (ICV) and group differences in body mass index and bone age. Results: CAH youth had smaller ICV and increased cerebrospinal fluid volume compared to controls. In fully-adjusted models, CAH youth had smaller bilateral, superior and caudal middle frontal volumes, and smaller left lateral orbito-frontal volumes compared to controls. Medial temporal lobe analyses revealed the left hippocampus was smaller in fully-adjusted models. CAH youth also had significantly smaller lateral nucleus of the amygdala and hippocampal subiculum and CA1 subregions. Conclusions: This study replicates previous findings of smaller medial temporal lobe volumes in CAH patients, and suggests that lateral nucleus of the amygdala, as well as subiculum and subfield CA1 of the hippocampus are particularly affected within the medial temporal lobes in CAH youth

Introduction to and Screening Visit Results of the Multicenter Pediatric Crohn's Disease Growth Study.

BackgroundStatural growth impairment is more common in males with Crohn's disease (CD). We assessed sex differences in height Z score differences and bone age (BA) Z scores and characterized age of menarche in a novel contemporary cohort of pediatric CD patients undergoing screening for enrollment in the multicenter longitudinal Growth Study.MethodsCrohn's disease patients (females with chronological age [CA] 5 years and older and younger than 14 years; males with CA 6 years and older and younger than 16 years) participated in a screening visit for the Growth Study. Height BA-Z scores are height Z scores calculated based on BA. Height CA-Z scores are height Z scores calculated based on CA. The height Z score difference equals height CA-Z score minus height BA-Z score.ResultsOne hundred seventy-one patients (60% male) qualified for this analysis. Mean CA was 12.2 years. Mean height CA-Z score was -0.4, and mean height BA-Z score was 0.4 in females. Mean height CA-Z score was -0.1, and mean height BA-Z score was 0.2 in males. The absolute value of the mean height Z score difference was significantly greater in females (0.8) than males (0.3; P = 0.005). The mean BA-Z score in females (-1.0) was significantly lower than in males (-0.2; P = 0.002). The median CA at menarche was 13.6 (95% CI, 12.6-14.6) years.ConclusionsOur screening visit data suggest that standardized height gain is lower in males with skeletal maturation and delayed puberty is common in females in CD. We are investigating these findings in the ongoing Growth Study

Ossification Of The Phalanges Of The Foot And Its Relationship To Peak Height Velocity And The Calcaneal System

Background: There are multiple skeletal maturity grading systems, but none of them utilizes the phalanges of the foot. To minimize radiation, it would be ideal if one could assess the skeletal maturity of a foot based on bones seen on routine foot x-rays, if guided growth is being considered as a treatment option, as in hallux valgus. We developed a system that in combination with the calcaneal system, can closely predict skeletal maturity and help with the timing of surgical interventions of the foot. Methods: We selected 94 healthy children from the Bolton-Brush study, each with consecutive radiographs from age ten to fifteen years old. Using the AP view, we analyzed the ossification patterns of the phalanges and developed a six stage classification system. We then determined the Peak Height Velocity (PHV) for each subject and defined its relationship with our system. Our system was then compared to the previously established calcaneal system. Results: We calculated an Intraclass correlation coefficient (ICC) range of 0.957-0.985 with an average of 0.975 and interclass reliability coefficient of 0.993 indicating that this method is reliable and consistent. Our system showed no significant difference between sexes, with respect to PHV, which makes it a reliable surrogate for determining bone age in pediatric and adolescent patients. Conclusions: Our system has a strong association with the calcaneal system. It is reliable and correlated more strongly with PHV than chronological age. The system requires knowledge of the ossification markers used for each stage but is easily used in a clinical setting

Semi-Supervised Self-Taught Deep Learning for Finger Bones Segmentation

Segmentation stands at the forefront of many high-level vision tasks. In this study, we focus on segmenting finger bones within a newly introduced semi-supervised self-taught deep learning framework which consists of a student network and a stand-alone teacher module. The whole system is boosted in a life-long learning manner wherein each step the teacher module provides a refinement for the student network to learn with newly unlabeled data. Experimental results demonstrate the superiority of the proposed method over conventional supervised deep learning methods.Comment: IEEE BHI 2019 accepte

Skeletal Maturity Assessment: Calcaneal Apophyseal Ossification

Background: Skeletal maturity scoring systems are used to gauge the amount of growth that a child has experienced and the amount of growth that remains. Studies have shown that skeletal maturity is more closely linked to time of peak height velocity (PHV) than chronological age. At PHV, skeletal maturity is very similar between children regardless of sex. Determination of PHV is important for orthopaedic decisions such as timing of epiphysiodesis and risk of scoliosis curve progression. However, the few existing systems of maturity assessment that can identify PHV have limitations preventing them from being used clinically or from predicting PHV beginning at an early age. Ossification of the calcaneal apophysis has never been fully characterized. We examined the ossification sequence of the calcaneus in relation to timing of peak height velocity (PHV). We compare calcaneal apophyseal ossification to other systems of maturity assessment including the Sanders hand score and the modified Oxford hip score. Also, we compare calcaneal apophyseal ossification to the ossification sequence of the plantar and thenar sesamoids, the triradiate cartilage (TRC), and the iliac apophysis. Methods: Ninety-four healthy children (forty-nine females and forty-five males) between ages three and eighteen were followed longitudinally through their growth with annual serial radiographs and physical examinations. We had approximately seven hundred serially acquired sets of foot, hip, and hand radiographs. PHV was calculated using the height measurements of each child. We compared to PHV the extent of calcaneal apophyseal ossification, iliac crest apophyseal ossification, Sanders hand scores, thenar and plantar sesamoid appearance, the TRC, and modified Oxford hip scores using radiographs taken on the same day annually over a minimum five year period. Results: Excursion of the calcaneal apophysis begins with appearance of the ossification center approximately five years prior to PHV and can be divided into six stages that occur over a seven year period. Four of six stages of calcaneal apophyseal ossification and two of eight stages of the Sanders system occur prior to PHV. The areas of overlap of the calcaneal and Sanders stages allow the two maturity systems to be combined for superior localization of maturity. The plantar and thenar sesamoids offer the ability to quickly deduce maturity and clarify stages of the calcaneal and Sanders systems. If the plantar sesamoids are present, and the thenar sesamoids are absent, the child is in between 1.35 to 0.12 years before PHV. Calcaneal stages 0-3, and Sanders hand scores 1-2 are associated with modified Oxford hip scores indicating substantial risk of contralateral SCFE. Conclusions: Ossification of the calcaneal apophysis can determine skeletal maturity around the time of adolescence. The calcaneal system can best identify maturity in the five years prior to PHV whereas the Sanders system better localizes maturity in time after PHV. Combinations of maturity systems allow for more precise localization of maturity than single systems alone. The calcaneal, Sanders system, and TRC can stratify children at high risk of contralateral SCFE. Identification of the most suitable maturity system to answer a clinical question depends on the certainty of the maturity indicator and the strength of the clinical association. If a maturity indicator is certain, and the clinical association of the maturity indicator is strong, additional maturity measurements are not needed. However, if either the maturity indicator or the clinical association is uncertain, further certainty can be obtained by considering a second maturity marker in conjunction, as shown through the improved power of the combined calcaneal/Sanders system for identification of PHV and prediction of contralateral SCFE

Assessment of reliability of Greulich and Pyle (gp) method for determination of age of children at Debre Markos Referral Hospital, East Gojjam Zone

Background: Greulich and Pyle standards are the most widely used age  estimation standards all over the world. The applicability of the Greulich and  Pyle standards to populations which differ from their reference population is  often questioned. This study aimed to assess the reliability of Greulich and Pyle (GP) method for determination of age of children at Debre Markos Referral Hospital, East Gojjam Zone, Ethiopia. Subjects and Methods: Hospital based cross sectional study design was  applied to children who came to Debre Markos Referral Hospital from May to October 2015 and fulfilled the inclusion criteria of the study. The data was  analyzed using SPSS version 20 and medcalc version 15 softwares.  Significance was set at α = 0.05. Results: A total of 108 radiographs were analyzed. Chronological age in most of the children was under estimated. The mean under-estimation was 11.8  months in the female sample and 8.7 months in the male sample. Greulich and Pyle method became inapplicable for the sample at 16 years for females and 16.5 years for males and later. Delay in skeletal maturation was observed in both sexes, but the females in the sample matured earlier than the males. Conclusion: The findings of this study suggest against the applicability of GP atlas which were not directly applicable to an East Gojjam Zone population. Large scale studies should be planned and nationwide guideline, and atlas which can easily be used throughout the country should be developed.  Keywords: Chronological age, bone age, Greulich and Pyl

Bone Age practices in infants and older children among practicing radiologists in Pakistan: Developing world perspective

Objective To investigate which bone age assessment techniques are utilized by radiologists in Pakistan to determine skeletal age in three defined age groups: less than one year, one to three years and three to 18 years. We also assessed the perceived confidence in skeletal age assessments made by respondents using their chosen bone age assessment technique, within each defined age group. Materials and methods A cross-sectional survey was conducted among 147 practicing radiologists in Pakistan. A pre-validated survey form was adopted from a similar study conducted amongst members of the Society for Pediatric Radiology. The survey collected demographic information, choice of bone age assessment technique in each age group and confidence of bone age assessments in each age group. Results The hand-wrist method of Greulich and Pyle was used by 87.5% of respondents when assessing bone age in infants (less than one year), followed by Gilsanz-Ratib hand bone age method (7.3%). In children aged one to three years, Greulich and Pyle method was chosen by 85.7% of respondents, followed by Gilsanz-Ratib hand bone age method (6.1%) and the Hoerr, Pyle, Francis\u27 Radiographic Atlas of Skeletal Development of the Foot and Ankle (3.1%). In children, older than three years, the Greulich and Pyle technique was used by 83.7% of respondents. This was followed by Gilsanz-Ratib hand bone age method (5.8%) and the Hoerr, Pyle, Francis\u27 Radiographic Atlas of Skeletal Development of the Foot and Ankle (3.8%). 26.4% were very confident in bone age assessments conducted among infants. In children aged one to three years, 38.1% were very confident . In children, greater than three years, 48.6% were very confident in their chosen technique. Conclusion Greulich and Pyle is the dominant method for bone age assessments in all age groups, however, confidence in its application among infants and young children is low. It is recommended that clear recommendations be developed for bone age assessments in this age group alongside incorporation of indigenous standards of bone age assessments based on a representative sample of healthy native children