Research Progress on Computer-Aided Skeleton-Based Individual Identification in Forensic Radiology / 法医学杂志

Individual identification based on imaging data of the skeleton of a corpse is a key technique for forensic identification. To reduce the influence of artificial factors, computer-aided semi-automatic or automatic individual identification has become one of the research directions of skeleton-based individual identification in forensic radiology. Therefore, this paper reviews and summarizes literatures related to estimation of anthropological information such as, age and sex by computer-aided forensic radiology bone characteristics and individual identification based on bone imaging characteristics, in order to provide reference on skeleton-based individual identification in forensic radiology.

Research Progress on Individual Identification by Frontal Sinus Imaging / 法医学杂志

Frontal sinus imaging is an important research object in forensic individual identification due to the highly specific irregular air cavity shape of frontal sinus, the stability of its shape after maturity, and the wide clinical application of radiology technology. The use of frontal sinus imaging for individual identification has significance in the court. When the application of traditional individual identification methods such as fingerprint identification and DNA analysis are limited or cannot be effectively carried out, or when the corresponding dental records are lacking and in other special cases, individual identification with frontal sinus imaging comparison is an effective alternative. Various types of image data can be used for individual identification with frontal sinus, mainly based on artificial visual comparing. With limitations such as, high professional requirements, low efficiency and small application range, the methods cannot be used in mass disasters. In recent years, some computer image recognition techniques have been used in identification of frontal sinus imagings and can significantly improve the efficiency of recognition. Difficulties such as low manual recognition efficiency may be overcomed. This study summarizes the reports on forensic individual identification using frontal sinus imaging, to review the research progress on individual identification with frontal sinus imaging, to provide a reference for further research on frontal sinus imaging, and to provide ideas for exploration and establishment of a faster, more efficient and more accurate individual identification system.

Adult Age Estimation of CT Image Reconstruction of the Laryngeal Cartilages and Hyoid Bone Based on Data Mining / 法医学杂志

Objective To explore the feasibility of the CT image reconstruction of laryngeal cartilage and hyoid bone in adult age estimation using data mining methods. Methods The neck thin slice CT scans of 413 individuals aged 18 to <80 years were collected and divided into test set and train set, randomly. According to grading methods such as TURK et al., all samples were graded comprehensively. The process of thyroid cartilage ossification was divided into 6 stages, the process of cricoid cartilage ossification was divided into 5 stages, and the synosteosis between the greater horn of hyoid and hyoid body was divided into 3 stages. Multiple linear regression model, support vector regression model, and Bayesian ridge regression model were developed for adult age estimation by scikit-learn 0.17 machine learning kit （Python language）. Leave-one-out cross-validation and the test set were used to further evaluate performance of the models. Results All indicators were moderately or poorly associated with age. The model with the highest accuracy in male age estimation was the support vector regression model, with a mean absolute error of 8.67 years, much higher than the other two models. The model with the highest accuracy in female adult age estimation was the support vector regression model, with a mean absolute error of 12.69 years, but its accuracy differences with the other two models had no statistical significance. Conclusion Data mining technology can improve the accuracy of adult age estimation, but the accuracy of adult age estimation based on laryngeal cartilage and hyoid bone is still not satisfactory, so it should be combined with other indicators in practice.

Forensic Individual Identification Based on the New Coding Method of Oral Pano-ramic Tomography / 法医学杂志

Objective To discuss a new coding method for individual identification based on oral panoramic tomography, analyze the diversity of different coding modules in nonhomologous images and the consistency and the matching rate of the coding indexes of different coding modules in homologous images, and evaluate the application value of the different modules and the new coding method in individual identification. Methods The oral panoramic tomography images of 1 000 patients with permanent teeth were collected retrospectively. Each patient had two images taken at different times （called the Early database and the Late database according to the chronological order）. Each image was coded according to the designed coding method. A computer program was designed to compare the diversity of different modules, and calculate the diversity and consistency of different coding modules as well as the matching rate of the coding indexes. Results The diversity of the 4 modules that reflected teeth characteristics was much higher than that of other modules in the same database. The highest diversity was noticed in the module of right mandibular teeth in samples of both databases. The coding consistencies of the 4 modules were all above 50%. Besides, 90.2% of the matching rates of indexes of homologous images were over 80%. Conclusion The 4 modules have higher application value in individual identification, especially the right mandibular teeth. The coding method has a certain value in forensic individual identification.

Sex Estimation of Typical Adult Vertebrae Morphology in Central China Based on CT Technique / 法医学杂志

Objective The morphological data of the second thoracic vertebra and the third lumbar vertebra were measured by computerized tomography （CT）. The sex differences were analyzed and the discrimination equation was obtained. Methods The data of 274 adults （203 cases from experimental group and 69 cases from validation group） from central China were collected. Four linear data （maximum transverse length of vertebral body, maximum longitudinal length of vertebral body, maximum transverse length of vertebral foramen, maximum longitudinal length of vertebral foramen）, one angle data （angle between spinous processes） and two area （vertebral foramen area, total cross-sectional area of vertebral body） data of the second thoracic vertebra and the third lumbar vertebra were collected, respectively. Then three ratios ［maximum transverse length/　maximum longitudinal length of vertebral body, maximum transverse length/ maximum longitudinal length of vertebral foramen, vertebral foramen area/ （total cross-sectional area of vertebral body-vertebral foramen area）］ and one angle （angle between spinous processes） were obtained. The discriminant equation was established for sexual discriminant analysis. Results The morphology of the second thoracic vertebra and the third lumbar vertebra was related with gender. Four single index discriminant formulae and eleven multi-index discriminant formulae were established. The 69 validation group samples were substituted into the formula for testing, and the maximum discriminant accuracy rate of the single-index discriminant formula was 75%. The maximum discriminant accuracy rate of multi-index discriminant formula was 83%. Conclusion It is feasible to conduct individual sex analysis by the morphological indexes of second thoracic vertebra and the third lumbar vertebra. The indexes have important application values in practice.

Estimation of Sex from Patella Measurements in Sichuan Han Population Based on CT-Three-Dimensional Volume Reconstruction Technique / 法医学杂志

Objective To estimate sex based on patella measurements of Sichuan Han population by computed tomography three-dimensional volume reconstruction technique, and to explore the application value of patella in sex estimation. Methods CT three-dimensional volume reconstruction images of patella of 250 individuals were collected, the four measurement indicators including patellar length, patellar width, patellar thickness, and patellar volume were measured. The t-test was used to determine measurement indicators with sex differences. Fisher discriminant analysis was used to establish the sex discriminant function and the prediction accuracy was calculated by leave-one-out cross validation. Results The sex differences of the four measurement indicators had a statistical significance （P<0.05）. The accuracy rate of the univariate discriminant function established by the patellar length was the highest （82.0%）. The accuracy rates of the all indicators discriminant function and the stepwise discriminant function were 80.4% and 81.6%, respectively. Conclusion It is feasible and accurate to estimate sex of Sichuan Han population by patella measurements with CT three-dimensional volume reconstruction technique. The method may be used as an alternative for sex estimation of Sichuan Han population when other bones with higher accuracy are not available.

Research Progress of Adult Age Determination with Imaging Methods / 法医学杂志

Adult age determination plays an important role in individual identification, criminal investigation and social welfare. The most popular adult age determination indicators are pubic symphysis, iliac auricular surface, costal cartilage, cranial sutures, teeth, laryngeal cartilage, etc. In recent years, with the progress of CT imaging and 3D reconstruction technology, the adult age determination study gradually has transferred from a time-consuming general observation of bones with complex pre-processing in the past to the non-destructive, convenient, time-saving and easy to store image analysis technology. To explore more accurate, rapid and convenient adult age determination methods, multiple imaging methods and artificial intelligence have been applied in adult age determination. This paper reviews the common methods and research progress of adult age determination at home and abroad, infers the development direction of adult age determination, in order to provide reference for the improvement and optimization of forensic adult age determination.

Research Progress on the Forensic Age Estimation in Living Individuals Using MRI / 法医学杂志

One of the major tasks in the forensic field is age estimation in living individuals, especially in adolescents and young adults. The X-ray examination of left hand, panoramic radiograph and CT scan of the sternal end of clavicles are mature means that are widely used. However, the X-ray technique has great radiation on the human body, and imaging radiation for non-diagnosis and treatment purposes does not conform to the current mainstream medical ethics. MRI is nonradioactive tomographic imaging and is one of the research and development directions in forensic age estimation in living individuals now. This paper summarizes the common indicators and analysis methods of MRI in previous research of age estimation, in order to get better understanding of its trends and provide a clue for future relevant studies.

Age Estimation in Han Adults by Thin-Layer CT Scan of Cranial Sutures / 法医学杂志

Objective To explore the value of degree of cranial suture closure in forensic adult age estimation by thin-layer CT scan and establish an adult age estimation model of the Han nationality. Methods Thin-layer CT scan samples of the heads of 220 healthy Sichuan Han adults （110 males, 110 females） aged 20 to 70 were collected, of which 20 samples （10 males, 10 females） were randomly selected as test samples. The sagittal suture, coronal suture （both left and right） and lambdoid suture （both left and right） were respectively and equally divided into 2 segments, and every segment was equally divided into 10 layers and the corresponding multiplanar reformation （MPR） images were selected. The closure of cranial sutures on MPR images was classified into the grades 1-7. The correlations between cranial sutures and age were analyzed to build regression equation for age estimation. Results The degree of closure of sagittal suture, coronal suture （both left and right） and lambdoid suture （both left and right） was positively correlated with age. The coefficient of determination （R2） of regression equation was 0.419 in males, 0.589 in females, and 0.522 in all samples. The results of the verification test showed that the mean absolute error （MAE） was 6.39 years in males, 6.16 years in females, and 6.29 years in all samples. Conclusion There was a higher accuracy in adult age estimation by thin-layer CT scan of cranial sutures. The age of Han nationality adults can be estimated by the degree of cranial sutures closure.

Research Progress on Automatic Assessment of Bone Age / 法医学杂志

Bone age is an important indicator of human growth and development, which can objectively reflect the growth level and maturity of individuals. Traditional manual bone age assessment usually compares the X-ray of the left wrist with the reference standard to obtain the corresponding bone age. This method is time-consuming and its results vary with different observers. In recent years, with the continuous development of computer science, bone age assessment has began to change from traditional manual assessment to automatic assessment. Although there has already been numerous researches on automatic bone age assessment, most of them are still in the experimental stage. This paper reviews related research and progress on automatic bone age assessment at home and abroad in recent years, in order to provide reference and research ideas for relevant researchers.

Retrospective Analysis on 1 900 Cases of Medical Malpractices / 法医学杂志

Objective To study the change trend, distribution characteristics and causes of medical malpractices in 18 years, through retrospective analysis of 1 900 cases of medical malpractices, in order to provide guidance for the precaution and the treatment of medical malpractices. Methods A thousand and nine hundred medical malpractice cases that were accepted by Hunan Xiangya Judical Identification Center from 2000 to 2017 were collected. Statistical analysis on the caseloads, the clients, the department distributions, the levels of the hospital and the causes of medical malpractices, etc were conducted. Results The number of cases commissioned by third-party accreditation agencies for medical fault identification was on the rise; The clients of medical malpractices changed significantly in 18 years. Most of the medical malpractice cases occurred in secondary and tertiary hospitals, significantly more in surgery, obstetrics and gynecology. The occurrence of medical malpractices was related to the doctor's insufficient prediction of the severity of the disease and the possible complications, and failure to fully inform the relevant duty of care, etc. Conclusion China's medical malpractice solutions and medical fault identification procedures are gradually improving. Strengthening the medical malpractice precaution awareness of medical workers in surgery, obstetrics and gynecology will be conducive to resolution of medical malpractices.

Stature Estimation of Sichuan Han Females Based on X-ray Photography of Total Lower Limbs / 法医学杂志

OBJECTIVES@#To establish a mathematical model of stature estimation for Sichuan Han females on the basis of the relationship between lower limbs and individual height, thus to provide evidence for forensic identification.@*METHODS@#Samples were collected from 171 Sichuan Han females. Large flat panel multi-function digital photography system was used to take the full-body X-ray films of the lower limbs. Indexes of long bones and stature of the subjects were measured, respectively. A linear regression analysis was carried out on the correlation between them, and a mathematical model of the stature calculation was established. Then the mathematical model was used to calculate the stature of another 29 Sichuan Han females to test its accuracy.@*RESULTS@#The maximum length of femur （x1） had the highest correlation with stature. A total of 13 linear regression equations were established （P<0.05）, with the correlation coefficient （R） 0.821-0.897 and the standard error of the estimation （SEE） 2.994-3.812 cm. The backtesting showed that the equation y=41.604+1.205 x1+1.318 x6+2.444 x12+1.852 x13-2.388 x14 had the smallest mean absolute deviation （2.485 years old） and the highest accuracy of ±2SEE （92.9%）, and that the equation y=48.783+2.568 x1 had the highest accuracy of ±1SEE （60.7%）.@*CONCLUSIONS@#The stature estimation is high by using the long bones of the lower limbs has high accuracy.

Stature Estimation for Sichuan Han Female Based on Whole-spine X-ray Photo-graphy / 法医学杂志

Objective To establish regression models of stature estimation for Sichuan Han female by the measurement of total vertebral column length in the frontal and lateral X-ray films of whole-spine. Methods The frontal and lateral X-ray films of whole-spine were collected from 200 Sichuan Han fe-males by large flat-panel multi-functional universal radiography and fluoroscopy system. The data and mean values of frontal and lateral total vertebral column length were measured and calculated in all the samples, respectively. The relationship of combined multi-markers and stature were analysed by linear regression analysis, and the mathematical models of stature estimation were established. The data of 30 new samples were selected and inputted for verifying the accuracy of the mathematical models. Results The total vertebral column length showed a good correlation with stature, and the mean values of the frontal and lateral X-ray films of total vertebral column length had the highest correlation coefficients. Three established linear regression equation models were statistically significant(P＜0.05), and the equa-tion established with lateral total vertebral column length showed the highest accuracy. Conclusion The stature estimation by the measurement of total vertebral column length has high accuracy.

Relationship between Body Height and Craniofacial Lines Measured by CT in Southwest Han Males / 法医学杂志

OBJECTIVE@#To establish regression model between craniofacial lines and body height by measuring craniofacial lines in Southwest Han males using CT and to accumulate data for the study of forensic anthropology.@*METHODS@#Head CT data of 273 Han males in Southwest were collected and 7 craniofacial lines were determined. Multiplanar reconstruction and volume rendering were performed by image post-processing software and the selected lines were measured. The relationship between each measuring indicator and body height was analyzed using SPSS 21.0 software. The regression equation of body height estimation was established and 50 samples were selected again and put into the mathematics models to verify its accuracy.@*RESULTS@#The linear regression equations of 7 lines were established (P < 0.05). The correlation coefficients of the unary linear regression equations were 0.190-0.439 and the standard errors of the estimate (SEE) were 4.597-5.023 cm. The correlation coefficients of the multiple linear regression equation were 0.494-0.524 and the SEE were 4.418-4.458 cm. The return tests showed that the highest ± 1SEE accuracy of the multiple regression equation: y = 83.959+3.589 x6+2.573 x2, were 30%; and the highest ± 2SEE accuracy of the multiple regression equation: y = 72.646+3.316 x6+1.586 x2+1.553 x4+2.211 x3, were 92%.@*CONCLUSION@#There is significant linear correlation between 7 selected lines and the stature in this study, and the plural linear regression equation established could be applied for estimating the stature of Southwest Han males.

Establish Assessment Model of 18 Years of Age in Chinese Han Population by Mandibular Third Molar / 法医学杂志

OBJECTIVE@#To explore the value of estimating chronologic age based on the grades of mandibular third molar development. To evaluate whether mandibular third molar could be used as an indicator for estimating the age under or over 18 years.@*METHODS@#The mineralization status of mandibular third molar of 1 845 individuals aged 10 - 30 was graded and marked based on Demirjian's classification of grades reformed by Orhan. Gender difference was examined by t-test. A cubic regression model was established to analyze the correlation between third molar and chronologic age. Each grade of age cumulative distribution diagram and ROC curve was respectively performed to evaluate the relationship between third molar and the age of 18. Using Bayes discriminant analysis, an equation was established for estimating the age of 18.@*RESULTS@#The inner-rater reliability was 0.903. Statistical analysis showed a moderate correlation between age and grade. Significant differences of both genders were found only in grade D and H (P < 0.05). Males at the grades from 1 to D and females at the grades from 1 to C were under 18 years old, and both males and females at grade H were over 18 years old. The area under the ROC curve was 0.797 (P < 0.05).@*CONCLUSION@#Third molar development shows a high correlation with age, and combined with other indicators, it can be used to estimate the age of 18.

Progress on the Rule of Clavicle Epiphyseal Closure Using Multi-Imaging Technology / 法医学杂志

People aged 18 years could be punished lightly or diminished criminal responsibility, even be spared the death sentence, which has important meaning in Chinese judicatory adjudication. The epiphysis of long bones from human limbs and the secondary sexual characteristics almost have developed completely before 18 years old. Clavicle epiphysis is one of the articular metaphysis which has a late epiphyseal closure. The recent studies in exploring the rule of clavicle epiphyseal by multi-imaging technology shows that the development of clavicle epiphysis has some value in age estimation of 18 years old. CT, especially thin-section CT, is widely used at present. However, thin-section CT scanning has great net radiation, which is not ethically acceptable if it is not for diagnosis and treatment. MRI is nonradioactive tomographic imaging and easy to evaluate, which is one of the future research directions in forensic age estimation using the medial clavicle. This paper summarizes the progress on the rule of clavicle epiphyseal closure, and analyzes and summarizes the feasibility of rule of clavicle epiphyseal closure applies on age estimation.

Relation between Body Height and Combined Length of Manubrium and Mesosternum of Sternum Measured by CT-VRT in Southwest Han Population / 法医学杂志

OBJECTIVE@#To establish the linear regression equation between body height and combined length of manubrium and mesostenum of sternum measured by CT volume rendering technique (CT-VRT) in southwest Han population.@*METHODS@#One hundred and sixty subjects, including 80 males and 80 females were selected from southwest Han population for routine CT-VRT (reconstruction thickness 1 mm) examination. The lengths of both manubrium and mesosternum were recorded, and the combined length of manubrium and mesosternum was equal to the algebraic sum of them. The sex-specific linear regression equations between the combined length of manubrium and mesosternum and the real body height of each subject were deduced.@*RESULTS@#The sex-specific simple linear regression equations between the combined length of manubrium and mesostenum (x3) and body height (y) were established (male: y = 135.000+2.118 x3 and female: y = 120.790+2.808 x3). Both equations showed statistical significance (P < 0.05) with a 100% predictive accuracy.@*CONCLUSION@#CT-VRT is an effective method for measurement of the index of sternum. The combined length of manubrium and mesosternum from CT-VRT can be used for body height estimation in southwest Han population.

Analysis of deaths caused by secondary damages of road traffic accidents: 17 fatal cases / 法医学杂志

OBJECTIVE@#To explore the forensic identification points of deaths caused by secondary damages of road traffic accidents.@*METHODS@#Seventeen deaths caused by secondary damages of road traffic accidents were collected. Through scene investigation and necropsy, the basic information of the accidents, distribution and property of the injuries, and other information were collected. According to the collected data, the scene was reconstructed in order to confirm the injury process, analyze the way, mechanism and severity of injury, distinguish antemortem injury from postmortem injury, and determine the cause of deaths.@*RESULTS@#Certain features such as serious injuries, multiple traumas, combined injuries, co-existence of antemortem and postmortem injuries, multiple causes of wounds, complex injury mechanism, as well as the mutual damaging and overlapping injuries were quite characteristically noted in these secondary traffic accident cases.@*CONCLUSION@#Forensic assessment of deaths caused by secondary damages of road traffic accidents should be synthetically analyzed and judged through scene investigation and necropsy.

Stature estimation for Sichuan Han nationality female based on X-ray technology with measurement of lumbar vertebrae / 法医学杂志

OBJECTIVE@#To establish the mathematical models of stature estimation for Sichuan Han female with measurement of lumbar vertebrae by X-ray to provide essential data for forensic anthropology research.@*METHODS@#The samples, 206 Sichuan Han females, were divided into three groups including group A, B and C according to the ages. Group A (206 samples) consisted of all ages, group B (116 samples) were 20-45 years old and 90 samples over 45 years old were group C. All the samples were examined lumbar vertebrae through CR technology, including the parameters of five centrums (L1-L5) as anterior border, posterior border and central heights (x1-x15), total central height of lumbar spine (x16), and the real height of every sample. The linear regression analysis was produced using the parameters to establish the mathematical models of stature estimation. Sixty-two trained subjects were tested to verify the accuracy of the mathematical models.@*RESULTS@#The established mathematical models by hypothesis test of linear regression equation model were statistically significant (P<0.05). The standard errors of the equation were 2.982-5.004 cm, while correlation coefficients were 0.370-0.779 and multiple correlation coefficients were 0.533-0.834. The return tests of the highest correlation coefficient and multiple correlation coefficient of each group showed that the highest accuracy of the multiple regression equation, y = 100.33 + 1.489 x3 - 0.548 x6 + 0.772 x9 + 0.058 x12 + 0.645 x15, in group A were 80.6% (+/- lSE) and 100% (+/- 2SE).@*CONCLUSION@#The established mathematical models in this study could be applied for the stature estimation for Sichuan Han females.