Age estimation through histological study of trabecular volume and cortical bone width of the iliac crest

Machine learning and regression analysis for age estimation from the iliac crest based on computed tomographic explorations in an Indian population

Age estimation constitutes an integral parameter of identification. In children, sub-adults, and young adults, accurate age estimation is vital on various aspects of civil, criminal, and immigration law. The iliac crest presents as a suitable age marker within these age cohorts, and the modified Risser method constitutes a relatively novel and unexplored method for iliac crest age estimation. The present study attempted to ascertain the applicability of this modified method for age estimation in the Indian population, an aspect previously unexplored, through computed tomographic examination of the iliac crest. Computed tomography scans of consenting individuals undergoing routine examinations of the pelvis/ abdomen for various clinically indicated reasons were collected and scored using the modified Risser stages. Computed tomographic examinations of the iliac crest indicate that the recalibrated method accurately depicts the temporal progression of ossification and fusion changes. Different regression and machine learning models were subsequently derived and/or trained to evaluate the accuracy and precision associated with the method. Amongst the ten regression models derived herein, compound regression exhibited the lowest inaccuracy (4.78 years) and root mean squared error values (5.46 years). Machine learning yielded further reduced error rates, with decision tree regression achieving inaccuracy and root mean squared error values of 1.88 years and 2.28 years, respectively. A comparative evaluation of error computations obtained from regression analysis and machine learning illustrates the statistical superiority of machine learning for forensic age estimation. Error computations obtained with machine learning suggest that the modified Risser method is capable of permitting reliable age estimation within criminal and civil proceedings.

Quantifications of Mandibular Trabecular Bone Microstructure Using Cone Beam Computed Tomography for Age Estimation: A Preliminary Study

The aim of this study is two-fold: first, to correlate the values for each of the trabecular bone microstructure (TBM) parameters to the individual’s chronological age and sex, thereby facilitating the assessment of potential age and sex-related changes in trabecular bone microstructure parameters in the mandible; and second, to quantify the trabecular microstructural parameters in relation to chronological age. Twenty cone-beam computed tomographic (CBCT) scans were retrieved retrospectively from a database of adult patients with ages ranging in age from 22 to 43 years. In the mandible, the volume of interest included the inter-dental space between the second mandibular premolar and the first mandibular molar, as well as the trabecular space beneath and between the apices. Using the AnalyzeDirect 14.0 software, the DICOM images of CBCT scans were pre-processed, transformed, segmented using a novel semi-automatic threshold-guided method, and quantified. In addition, TBM parameters were derived, and statistical analysis was conducted using a Pearson correlation test with two tails. All parameters exhibited no statistically significant differences (p > 0.05) between chronological age and sex. Statistically significant negative correlations were found between Tb. N (r = −0.489), BS/TV (r = −0.527), and chronological age (p = 0.029 and p = 0.017, respectively). Only Tb. N and BS/TV exhibited an inverse relationship with chronological age. Numerous studies have quantified the trabecular architecture of the jaw bones, but none have found a correlation between the quantified trabecular parameters and chronological age. The digital imprints produced by radiographic imaging can serve as biological profiles for data collection.

Age related changes of rib cortical bone matrix and the application to forensic age-at-death estimation

Forensic anthropology includes, amongst other applications, the positive identification of unknown human skeletal remains. The first step in this process is an assessment of the biological profile, that is: sex, age, stature and ancestry. In forensic contexts, age estimation is one of the main challenges in the process of identification. Recently established admissibility criteria are driving researchers towards standardisation of methodological procedures. Despite these changes, experience still plays a central role in anthropological examinations. In order to avoid this issue, age estimation procedures (i) must be presented to the scientific community and published in peer reviewed journals, (ii) accurately explained in terms of procedure and (iii) present clear information about the accuracy of the estimation and possible error rates. In order to fulfil all these requirements, a number of methods based on physiological processes which result in biochemical changes in various tissue structures at the molecular level, such as modifications in DNA-methylation and telomere shortening, racemization of proteins and stable isotopes analysis, have been developed. The current work proposes a new systematic approach in age estimation based on tracing physicochemical and mechanical degeneration of the rib cortical bone matrix. This study used autopsy material from 113 rib specimens. A set of 33 parameters were measured by standard bio-mechanical (nanoindentation and microindentation), physical (TGA/DSC, XRD and FTIR) and histomorphometry (porosity-ImageJ) methods. Stepwise regressions were used to create equations that would produce the best 'estimates of age at death' vs real age of the cadavers. Five equations were produced; in the best of cases an equation counting 7 parameters had an R² = 0.863 and mean absolute error of 4.64 years. The present method meets all the admissibility criteria previously described. Furthermore, the method is experience-independent and as such can be performed without previous expert knowledge of forensic anthropology and human anatomy.

Age estimation equations using vertebral osteophyte formation in a Thai population: comparison and modified osteophyte scoring method

Age estimation from skeletal remains is an important step in forensic biological identification. The main objective of this study is to develop an age estimation equation for the Thai population from vertebral osteophytes. Each vertebra in the cervical, thoracic and lumbar segments was scored for degree of osteophyte formation. Classification was carried out in accordance with the criteria established by Snodgrass and Watanabe, and used a new modified score of the length of vertebral osteophyte for age estimation. The sample included 400 individuals (262 males, 138 females) ranging in age from 22 to 97 years. A sample of Thai vertebral columns was used, the columns being divided into the following groups of vertebrae: cervical (C2–C7), thoracic (T1–T12), and lumbar (L1–L5). Each vertebra was scored for the degree of osteophyte formation and the accumulated data was analyzed statistically. Correlation coefficients and R-squared from mean in lumbar vertebrae for females of criteria established by the method of Snodgrass and Watanabe, the new modified score by length of vertebral osteophytes were 0.801 and 0.642 (P<0.01); 0.755 and 0.57 (P<0.01); 0.786 and 0.618 (P<0.01), respectively. This study presents all 23 subcategories (C2–L5) of the vertebrae to apply in real situations, showing all age estimation equations for males, females and combined sexes of unknown sex. One application of this study is age estimation when dealing with forensic cases in the Thai population.

Stature estimation from tibia percutaneous length: New equations derived from a Mediterranean population

Stature is a fundamental anthropometric character to trace the biological profile of a person. In some cases, when dismembered or mutilated bodies are discovered in a forensic context, it is essential to estimate stature from single districts of the body. Nevertheless, to date and worldwide, there are only few population-specific studies on stature estimation from leg length and none of them concerns modern populations in southern Europe. We attempted to fill this gap, focusing on the estimation of stature from the length of the tibia in a Mediterranean population (Italians). We carried out the current study on a sample of 374 Italian university students of both sexes (age range: 19.9-34.4). Both, actual stature and percutaneous length of tibia were measured and new equations were developed for stature estimation. We tested separate regression equations for each sex, as well as an equation for remains, whose sex is unknown. To assess their reliability, the equations were tested on a holdout sample of 30 individuals from the same population. Moreover, results of new specific linear regression equations were compared to others from the literature. We demonstrated that the newly proposed formulae (for males and combined sexes) and the ones by Olivier (for females) provided the most reliable estimations of stature for southern Europeans.

Pulsed electromagnetic fields (PEMF) attenuate changes in vertebral bone mass, architecture and strength in ovariectomized mice

Pulsed electromagnetic fields (PEMF) has been investigated as a noninvasive alternative method to prevent bone loss for postmenopausal osteoporosis (OP), and the bone tissue involved in these studies are usually long bones such as femur and tibia in OP patients or rat models. However, few studies have investigated the effects of PEMF on the vertebral bone in mice with OP. This study aimed to investigate whether PEMF preserve lumbar vertebral bone mass, microarchitecture and strength in ovariectomized (OVX) mouse model of OP and its associated mechanisms. Thirty 3-month-old female BALB/c mice were randomly divided into three groups (n=10): sham-operated control (Sham), ovariectomy (OVX), and ovariectomy with PEMF treatment (OVX+PEMF). The OVX+PEMF group was exposed to 15Hz, 1.6 mT PEMF for 8h/day, 7days/week. After 8weeks, the mice were sacrificed. The OVX+PEMF group showed lower body weight gain of mice induced by estrogen deficiency compared with OVX group. Biochemical analysis of serum demonstrated that serum bone formation markers including bone specific alkaline phosphatase (BALP), serum osteocalcin (OCN), osteoprotegerin (OPG) and N-terminal propeptide of type I procollagen (P1NP) were markedly higher in OVX+PEMF group compared with OVX group. Besides, serum bone resorption markers including tartrate-resistant acid phosphatase 5b (TRAP-5b) and C-terminal crosslinked telopeptides of type I collagen (CTX-I) were markedly lower in OVX+PEMF group compared with OVX group. Biomechanical test observed that OVX+PEMF group showed higher compressive maximum load and stiffness of the lumbar vertebrae compared with OVX group. Micro-computed tomography (μCT) and histological analysis of lumbar vertebrae revealed that PEMF partially prevented OVX-induced decrease of trabecular bone mass and deterioration of trabecular bone microarchitecture in lumbar vertebrae. Real-time PCR showed that the canonical Wnt signaling pathway of the lumbar vertebrae, including Wnt3a, LRP5 and β-catenin were markedly up-regulated in OVX+PEMF group compared with OVX group. Moreover, the mRNA expressions of RANKL and OPG were markedly up-regulated in OVX+PEMF group compared with OVX group, whereas no statistical difference in RANKL/OPG mRNA ratio was found between OVX+PEMF group and OVX group. Besides, our study also found that the RANK mRNA expression was down-regulated in OVX+PEMF group compared with OVX group. Taken together, we reported that long-term stimulation with PEMF treatment was able to alleviate lumbar vertebral OP in postmenopausal mice through a combination of increased bone formation and suppressed bone resorption related to regulating the skeletal gene expressions of Wnt3a/LRP5/β-catenin and OPG/RANKL/RANK signaling pathways.

Iliac crest histomorphometry and skeletal heterogeneity in men

Purpose

The cortical characteristics of the iliac crest in male have rarely been investigated with quantitative histomorphometry. Also it is still unknown how cortical microarchitecture may vary between the iliac crest and fractures related sites at the proximal femur. We studied the microarchitecture of both external and internal cortices within the iliac crest, and compared the results with femoral neck and subtrochanteric femoral shaft sites.

Methods

Undecalcified histological sections of the iliac crest were obtained bicortically from cadavers (n = 20, aged 18–82 years, males). They were cut (7 μm) and stained using modified Masson-Goldner stain. Histomorphometric parameters of cortical bone were analysed with low (× 50) and high (× 100) magnification, after identifying cortical bone boundaries using our previously validated method. Within cortical bone area, only complete osteons with typical concentric lamellae and cement line were selected and measured.

Results

At the iliac crest, the mean cortical width of external cortex was higher than at the internal cortex (p < 0.001). Also, osteon structural parameters, e.g. mean osteonal perimeter, were higher in the external cortex (p < 0.05). In both external and internal cortices, pore number per cortical bone area was higher in young subjects (≤ 50 years) (p < 0.05) while mean pore perimeter was higher in the old subjects (> 50 years) (p < 0.05). Several cortical parameters (e.g. osteon area per cortical bone area, pore number per cortical area) were the lowest in the femoral neck (p < 0.05). The maximal osteonal diameter and mean wall width were the highest in the external cortex of the iliac crest (p < 0.05), and the mean cortical width, osteon number per cortical area were the highest in the subtrochanteric femoral shaft (p < 0.05). Some osteonal structural parameters (e.g. min osteonal diameter) were significantly positively correlated (0.29 ≤ R² ≤ 0.45, p < 0.05) between the external iliac crest and the femoral neck.

Conclusions

This study reveals heterogeneity in cortical microarchitecture between the external and internal iliac crest cortices, as well as between the iliac crest, the femoral neck and the subtrochanteric femoral shaft. Standard iliac crest biopsy does not reflect accurately cortical microarchitecture of other skeletal sites.

•

The structural asymmetry between cortices of the ilium remains after childhood.

•

In both cortices of the ilium, cortical pore perimeter was higher in the old subjects.

•

The cortical microarchitecture is highly variable between different skeletal sites.

•

Positive correlation is revealed between the external iliac crest and the femoral neck in osteonal characteristics.

Magnetic resonance imaging of the iliac crest: age estimation in under-20 soccer players

Age assessment of living individuals represents a valuable tool in both forensic medicine and sports medicine. In soccer, age-related tournaments play an important role in guaranteeing equal chances to the competitors. However, age estimations in this field should not rely on imaging methods that include exposure to radiation. Therefore, the present study investigates the possibilities of magnetic resonance imaging (MRI) of the iliac crest apophysis for the purpose of evaluating skeletal maturation in under-20 (U-20) soccer players. To this end, gradient echo 3D sequences of the whole pelvis of 152 male tournament soccer players between 18 and 22 years of age were prospectively evaluated. A four stage classification system was applied for the assessment of the apophyseal ossification. Reliable stage determination was possible in all cases. Further sub-classification did not appear feasible due to the limitations of MRI. Analysis of the statistical parameters showed that age medians increased steadily from stage to stage. However, they did not allow for further differentiation of skeletal maturity in the cohort studied. Thus, MRI of the iliac crest appears to be generally suitable in age diagnostics of living individuals, but further investigations, especially in a cohort of individuals aged between 10 and 20 years, are needed in order to establish this method as novel criterion in sports or forensic medicine.

Estimation of legal age using calcification stages of third molars in living individuals

The increased number of adolescents and young adults with unknown or inaccurately given date of birth is a current issue in justice and legal medicine. The objective of this study was to determine the extent to which third molar calcification stages assessed on panoramic X-rays could be useful as additional criteria for forensic age estimation in living individuals, focusing on the legally important ages 17 and 18. In a retrospective multi-center study, the developmental stage of each individual's third molar was analyzed using Demirjian's scale in 2360 cases. Additionally, sex, age and ancestry were assessed. Individuals with the lowest calcification stage of all present molars in stage H were ≥18 years with a likelihood of ≥99.05% in the female (n=388), and ≥99.24% in the male (n=482) population. The lowest calcification stage of all present third molars proved to be useful as an additional reliable criterion for the determination of an age ≥18 years.

Sonographic examination of the apophysis of the iliac crest for forensic age estimation in living persons

The present study examines the applicability of ultrasound diagnostics in assessing the ossification processes of the apophysis of the Crista iliaca of the pelvis for the purposes of forensic age diagnostics in living persons. To this end, the apophyseal ossification stages were determined in 307 female and 309 male study participants aged between 10 and 25 years. In females, ossification stage I was identifiable at an age of 10.1 years at the earliest (x¯=11.8), ossification stage II at 11.2 years at the earliest (x¯=14.6), ossification stage III at 14.7 years at the earliest (x¯ =18.6), and ossification stage IV at 17.9 years at the earliest (x¯=22.7). In males, ossification stage I was observable from an age of 10.0 years (x¯=11.8), ossification stage II from 10.5 years (x¯=14.9), ossification stage III from 15.6 years (x¯=18.9), and ossification stage IV from 17.4 years (x¯=22.6). In forensic age estimation procedures in living persons, sonographic examination of the iliac crest apophysis makes it possible to minimise exposure of the individual to radiation in accordance with the existing legal basis for the use of X-rays on humans. In application areas with no legal basis to justify X-ray examinations, the accuracy of an age diagnosis can be improved by integrating skeletal maturity as a criterion.