Post-mortem radiological CT identification based on classical ante-mortem X-ray examinations

Gray-Scale Extraction of Bone Features from Chest Radiographs Based on Deep Learning Technique for Personal Identification and Classification in Forensic Medicine

Post-mortem (PM) imaging has potential for identifying individuals by comparing ante-mortem (AM) and PM images. Radiographic images of bones contain significant information for personal identification. However, PM images are affected by soft tissue decomposition; therefore, it is desirable to extract only images of bones that change little over time. This study evaluated the effectiveness of U-Net for bone image extraction from two-dimensional (2D) X-ray images. Two types of pseudo 2D X-ray images were created from the PM computed tomography (CT) volumetric data using ray-summation processing for training U-Net. One was a projection of all body tissues, and the other was a projection of only bones. The performance of the U-Net for bone extraction was evaluated using Intersection over Union, Dice coefficient, and the area under the receiver operating characteristic curve. Additionally, AM chest radiographs were used to evaluate its performance with real 2D images. Our results indicated that bones could be extracted visually and accurately from both AM and PM images using U-Net. The extracted bone images could provide useful information for personal identification in forensic pathology.

Fire-damage findings in post-mortem CT

Post-mortem computed tomography (CT) can provide useful insights into coronial and forensic pathological investigation of the fire-damage victim. Understanding the pathological changes that can occur in fatalities caused by fire, particularly in relation to fire damage to the body, is paramount in attempting to distinguish ante-mortem and peri-mortem blunt traumatic injuries from fire-related damage to the body. Understanding the fire-damage features on post-mortem CT may also assist in determining cause of the fire and associated fire-damage. Although the requirements of radiological evaluation in post-mortem imaging are very different to those of day-to-day clinical ante-mortem imaging, foremost is a high-resolution CT protocol of the entire body in order to fulfil the requirements and expectations of such imaging and radiological interpretation.

Cause of Death in Charred Bodies: Reflections and Operational Insights Based on a Large Cases Study

Our study aims to demonstrate the experience of analyzing fully or partially charred corpses to offer a proper implementation protocol for determining the cause of death. In this study, we present a total of 103 cases obtained from the University of Rome La Sapienza and the University of Pisa archives. All cases were classified based on the extent and severity of burns using a visual method. We divided all cases into two groups. The first group included grade I-II burns (21 cases) without the need for identification. The second group (82 cases) included injuries worse than grade burns II, so all cases were analyzed using an analytical method. For each case, we have documented which of the following analyses have been used and the corresponding findings: inspection, autopsy examination, imaging examination, genetic and toxicological examinations, and histological examination. The results describe the main diagnostic findings and show that only the application of all the above systematic analyses can provide greater accuracy and reliability in describing the causes of death or solving problems, such as identification. In conclusion, we propose an available protocol that defines the main steps of a complete diagnostic pathway that pathologists should follow daily in studying charred bodies.

Frontal sinuses as tools for human identification: a systematic review of imaging methods

The frontal sinuses are potential evidences for human identification because of the inherent distinctiveness of their morphology. Over the last decades, several techniques emerged to enable the visualization and analysis of the frontal sinuses via bi- and three-dimensional imaging. This systematic review aimed to compile different methodological approaches found in the scientific literature to contribute to human identification. Three examiners revisited the scientific literature in order to find imaging techniques for the visualization of the frontal sinuses applied to human identification. The standard search strings built-up from a PICO question identified 404 unique articles in the following databases Medline/Pubmed, Web of Science, Scopus, Lilacs and Scielo. Based on eligibility criteria applied during title, abstract and full-text reading, the sample reduced to 19 articles. The articles were published between 1987 and 2019 by research groups from 10 different countries. Computed tomography was used in 37% of the techniques, while the remaining (63%) techniques used skull radiographs. The techniques were highly heterogeneous and varied between metric analysis, direct image superimposition and morphology code-based systems. The authors considered their techniques useful for human identification and reported accuracy rates from 13 to 100%. Most of the studies revealed low risk of bias. More advantages were related with the techniques based on direct image superimpositions and three-dimensional visualization. Forensic experts must be aware of the use of frontal sinuses for human identification, especially when three-dimensional images are available as ante-mortem and post-mortem evidences for superimposition and comparison.

Pitfalls of Computed Tomography 3D Reconstruction Models in Cranial Nonmetric Analysis

Many studies in the literature have highlighted the utility of virtual 3D databanks as a substitute for real skeletal collections and the important application of radiological records in personal identification. However, none have investigated the accuracy of virtual material compared to skeletal remains in nonmetric variant analysis using 3D models. The present study investigates the accuracy of 20 computed tomography (CT) 3D reconstruction models compared to the real crania, focusing on the quality of the reproduction of the real crania and the possibility to detect 29 dental/cranial morphological variations in 3D images. An interobserver analysis was performed to evaluate trait identification, number, position, and shape. Results demonstrate a false bone loss in 3D models in some cranial regions, specifically the maxillary and occipital bones in 85% and 20% of the samples. Additional analyses revealed several difficulties in the detection of cranial nonmetric traits in 3D models, resulting in incorrect identification in circa 70% of the traits. In particular, pitfalls included the detection of erroneous position, error in presence/absence rates, in number, and in shape. The lowest percentages of correct evaluations were found in traits localized in the lateral side of the cranium and for the infraorbital suture, mastoid foramen, and crenulation. The present study highlights important pitfalls in CT scan when compared with the real crania for nonmetric analysis. This may have crucial consequences in cases where 3D databanks are used as a source of reference population data for nonmetric traits and pathologies and during bone-CT comparisons for identification purposes.

Segmentation procedures for the assessment of paranasal sinuses volumes

BACKGROUND

The paranasal sinuses are complex anatomical structures, characterised by highly variable shape, morphology and size. With the introduction of multidetector scanners and the development of many post-processing possibilities, computed tomography became the gold standard technique to image the paranasal sinuses. Segmentation allows the extraction of metrical and shape data of these anatomical components that can be applied for diagnostic, education, surgical planning and simulation, and to plan minimally invasive interventions in otorhinolaryngology and neurosurgery.

DISCUSSION

Our aim was to provide a review of the existing literature on segmentation, its types and application, and the data obtained from this procedure. The literature search was conducted on PubMed (including Medline), ScienceDirect and Google Scholar databases, using the keywords as follows: 'paranasal sinuses', 'frontal sinus', 'maxillary sinus', 'sphenoid sinus', 'ethmoid sinus', in all possible combinations with the keywords 'segmentation' and 'volumetric analysis'. Inclusion criteria were: articles written in English, on living human subjects, on the adult population and focused on paranasal sinuses analysis.

CONCLUSION

This article provides an overview of the types and main application of segmentation procedures on paranasal sinuses, and the results provided by the studies on this topic.

Automated contour detection in spine radiographs and computed tomography reconstructions for forensic comparative identification

This study was conducted to test an automated method to identify unknown individuals. It relies on a previous radiographic file and uses an edge-based comparison of lumbar CT/PMCT reconstructions and radiographs. The living group was composed of 15 clinical lumbar spine CT scans and 15 paired radiographs belonging to the same patients. The deceased group consisted of 5 lumbar spine PMCT scans and 5 paired antemortem radiographs of deceased individuals plus the 15 unpaired radiographs belonging to the living. An automated method using image filtering (anisotropic diffusion) and edge detection (Canny filter) provided image contours. Cross comparisons of all the exams in each group were performed using similarity measurements under the affine registration hypothesis. The Dice coefficient and Hausdorff distance values were significantly linked (p < 0.001 and p = 0.001 respectively) to the matched examinations in the living group (p < 0.001; pseudo-R2 = 0.70). 12 of the 15 examinations were correctly paired, 2 were wrongly paired and 3 were not paired when they must have been. In the deceased group, the Hausdorff distance was significantly linked (p = 0.018) to the matched examinations (p < 0.001; pseudo-R2 = 0.62; Dice coefficient p = 0.138). The paired examinations were all correctly found, but one was wrongly paired. The negative predictive value was above 98% for both groups. We highlighted the feasibility of comparative radiological identification using automated edge detection in cross-modality (CT/PMCT scan and radiographs) examinations. This method could be of significant help to a radiologist or coroner in identifying unknown cadavers.

Three-dimensional analysis of sphenoid sinus uniqueness for assessing personal identification: a novel method based on 3D-3D superimposition

Sphenoid sinuses are considered the most variable structures of human body: therefore, they may be used for personal identification, through the application of 3D segmentation procedures. This study aims at proposing a new protocol for personal identification based on 3D-3D superimposition of sphenoid sinuses segmented from head CT scans. Adult subjects (equally divided among males and females) who underwent two head CT scans were extracted from a hospital database. Sphenoid sinuses were segmented through ITK-SNAP software and the corresponding 3D models were automatically superimposed to obtain 40 matches (when they belonged to the same person) and 260 mismatches (when they were extracted from different individuals). The RMS (root mean square) point-to-point distance was then calculated for all the superimpositions: differences according to sex and group (matches and mismatches) were assessed through the Mann-Whitney test (p < 0.05). On average, the RMS value was almost ten times smaller in matches (0.22 ± 0.11 mm) than in mismatches (2.16 ± 0.57 mm) with a statistically significant difference according to group (p < 0.05), but not to sex (p > 0.05). The study proposed a new method for assessing personal identification from segmented 3D models of sphenoid sinuses, useful in the forensic contexts where other methods might not be implementable or successful.

Virtopsy and Living Individuals Evaluation Using Computed Tomography in Forensic Diagnostic Imaging

The applications of forensic radiology involve both Virtopsy both studies on living people - to demonstrate bone age, search for foreign bodies, such as voluntary injection of drug ovules or surgical sponges accidentally forgotten, to assess gunshot wounds, to evaluate injuries by road accidents, and cases of violence or abuse (both in adults and in children). Computed tomography is the most used imaging tool used in forensic pathology and its indications are mainly focused on cases of unnatural deaths or when a crime is suspected. It is preferred over the standard autopsy in selected cases, such as in putrefied, carbonized or badly damaged bodies; or as a preliminary evaluation in mass disasters.

Virtual reconstruction of paranasal sinuses from CT data: A feasibility study for forensic application

PURPOSE

The purpose of this study was to report the feasibility of computed modelization and reconstitution of the paranasal sinuses, before and after trauma, from CT data.

MATERIALS AND METHODS

We modeled and reconstructed the paranasal sinuses of two patients (A and B), before and after trauma, using two different softwares (3DSlicer^® and Blender^®). Both patients had different numbers and locations of fractures. The 3DSlicer^® software was used to create a 3D model from CT data. We then imported the 3D data into the Blender^® software, to reconstruct and compare the dimensions of the paranasal sinuses before and after trauma.

RESULTS

The 3 fragments of patient A and the 7 fragments of patient B could be repositioned in the pre-traumatic configuration. Distance measurements proved to be similar between pre- and post-traumatic 3D volumes.

CONCLUSION

After simple trauma, bone facial anatomy reconstruction is manually feasible. The whole procedure could benefit from automatization through machine learning. However, this feasibility must be confirmed on more severely fractured paranasal sinuses, to consider an application in forensic identification.

An innovative 3D-3D superimposition for assessing anatomical uniqueness of frontal sinuses through segmentation on CT scans

Anatomical uniqueness plays a significant role in the personal identification process of unknown deceased. Frontal sinuses have been widely used in the past decades for this purpose, mostly using 2D X-ray techniques. However, the modern 3D CT-based segmentation methods may help in developing novel and more reliable methods of identification. This study aims at assessing the anatomical uniqueness of frontal sinuses through the 3D model registration. Thirty subjects who underwent two maxillofacial CT scans (interval: 1 month to 5 years) were selected from a hospital database. Frontal sinuses were automatically segmented through ITK-SNAP open source software and the 3D models belonging to the same patient were automatically superimposed according to the least point-to-point difference between the two surfaces. Two hundred patients were randomly selected from the same database and undergo the same procedure to perform 200 superimpositions of frontal sinuses belonging to different individuals, equally divided between males and females (mismatches). Statistically significant differences of average root mean square (RMS) point-to-point distance between the group of matches and mismatches, as well as possible differences according to sex, were assessed through Mann-Whitney U test (p < 0.05). In the group of matches, RMS ranged between 0.07 and 0.96 mm (mean RMS 0.35 ± 0.23 mm), while in the group of mismatches, it ranged between 0.96 and 10.29 mm (mean RMS 2.59 ± 1.79 mm), with a statistically significant difference (p < 0.0001). Neither the matches nor the mismatches group showed statistically significant differences according to sex. This study proposes a novel 3D approach for the assessment of anatomical uniqueness of frontal sinuses, providing both morphological and quantitative analysis, and a new method of identification based on 3D assessment of frontal sinuses, applicable when ante-mortem CT scans are available.

Standardized medical image registration for radiological identification of decedents based on paranasal sinuses

Image registration software is frequently used in clinical radiology, e.g., for follow-up diagnosis. To a certain extent, the radiological identification of decedents (RadID) is comparable to a clinical follow-up diagnosis, in that two datasets from different dates are compared in terms of their anatomical characteristics (e.g., paranasal sinuses) or surgical implants. Due to the increasing use of computed tomography (CT) for head examinations in clinical radiology and the increased use of postmortem CT (PMCT) in forensic imaging, the comparison of three-dimensional (3D) clinical CT (termed as antemortem CT (AMCT) in this article) and PMCT datasets for RadID is becoming increasingly practical. In particular, the comparison of paranasal sinuses in AMCT and PMCT imaging is considered a suitable and reliable modality for RadID. However, previous publications regarding RadID based on comparisons of 3D datasets have not considered the implementation of image registration to provide software-side support for RadID. This article demonstrates and evaluates the use of a standard medical image registration procedure for RadID by comparing paranasal sinuses.

Antemortem identification by fusion of MR and CT of the paranasal sinuses

Radiologic forensic identification is usually performed by comparing antemortem and postmortem radiographs. While computed tomography (CT) has become a valuable addition to radiologic identification, magnetic resonance (MR) imaging has only rarely been used for this purpose. In our case, identification was accomplished using fused MR- and CT images in a survivor of a gunshot injury to the head. This case supports and highlights the possibility to perform intermodality radiologic identification comparing preexisting MR imaging to subsequently aquired CT data in living (or deceased) humans as long as manual modifications of windowing, color and contrast enable differentiation of the two modalities in the fused image.

3D Multislice and Cone-beam Computed Tomography Systems for Dental Identification

3D Multislice and Cone-beam computed tomography (CBCT) in forensic odontology has been shown to be useful not only in terms of one or a few of dead bodies but also in multiple fatality incidents. 3D Multislice and Cone-beam computed tomography and digital radiography were demonstrated in a forensic examination form. 3D images of the skull and teeth were analysed and validated for long ante mortem/post mortem intervals. The image acquisition was instantaneous; the images were able to be optically enlarged, measured, superimposed and compared prima vista or using special software and exported as a file. Digital radiology and computer tomography has been shown to be important both in common criminalistics practices and in multiple fatality incidents. Our study demonstrated that CBCT imaging offers less image artifacts, low image reconstruction times, mobility of the unit and considerably lower equipment cost.

Contribution of the computed tomography of the anatomical aspects of the sphenoid sinuses to forensic identification

INTRODUCTION

Body identification is the cornerstone of forensic investigation. It can be performed using radiographic techniques, if antemortem images are available. This study was designed to assess the value of visual comparison of the computed tomography (CT) anatomical aspects of the sphenoid sinuses, in forensic individual identification, especially if antemortem dental records, fingerprints or DNA samples are not available.

MATERIAL AND METHODS

This retrospective work took place in a French university hospital. The supervisor of this study randomly selected from the picture archiving and communication system (PACS), 58 patients who underwent one (16 patients) or two (42 patients) head CT in various neurological contexts. To avoid bias, those studies were prepared (anonymized, and all the head structures but the sphenoid sinuses were excluded), and used to constitute two working lists of 50 (42+8) CT studies of the sphenoid sinuses. An anatomical classification system of the sphenoid sinuses anatomical variations was created based on the anatomical and surgical literature. In these two working lists, three blinded readers had to identify, using the anatomical system and subjective visual comparison, 42 pairs of matched studies, and 16 unmatched studies. Readers were blinded from the exact numbers of matching studies.

RESULTS

Each reader correctly identified the 42 pairs of CT with a concordance of 100% [97.5% confidence interval: 91-100%], and the 16 unmatched CT with a concordance of 100% [97.5% confidence interval: 79-100%]. Overall accuracy was 100%.

CONCLUSION

Our study shows that establishing the anatomical concordance of the sphenoid sinuses by visual comparison could be used in personal identification. This easy method, based on a frequently and increasingly prescribed exam, still needs to be assessed on a postmortem cohort.

Human identification study by means of frontal sinus imaginological aspects

The objective of this study was to evaluate the applicability of human identification parameters, established by Tatlisumak et al. (2007), by means of cone-beam computed tomography and extraoral radiographs of the frontal sinus region. From a total of 58 dry skulls, 26 were selected. Posteroanterior, profile cephalometric radiographs and cone-beam computed tomography images were acquired, adopting a specific method for reproducibility purposes. The images were evaluated by two examiners, previously calibrated, in a darkened environment and at two distinct sessions, with a minimum of 15 days between them. The characteristics of the frontal sinus were analyzed using the Cohen's kappa test, for categorical variables, and Lin's concordance correlation coefficient (CCC) for continuous variables. Acceptable values of inter method variability for the categorical variables were found, while same cannot be told for continuous variables. The parameters evaluated for the frontal sinus on extraoral radiographs and cone-beam computed tomographs were mostly concordant, with the exception of three. Categorical and discrete variables showed an intra- and interexaminer concordance ranging from good to perfect, and the quantitative continuous variables showed concordance ranging from moderate to excellent. The parameters examined are applicable and reproducible using multiplanar reconstructions of cone-beam computed tomography and extraoral radiographs of the frontal sinus.

Imaging for homicide investigations

The authors present the opportunities of the application of post-mortem imaging, focusing on post-mortem computed tomography and post-mortem computed tomography angiography in modern forensic investigation of homicide cases. The paper is based on scientific publications related to the subject from ca. the past 10 years, supplemented by the authors' own experiences. The article is illustrated with reconstructions based on the authors' own cases related to homicide due to ballistic/sharp/blunt trauma. As is shown, the results of evaluation of post-mortem computed tomography allow better diagnosis, documentation and visualisation of forensic examinations.

Virtual anthropology and forensic identification using multidetector CT

Virtual anthropology is made possible by modern cross-sectional imaging. Multislice CT (MSCT) can be used for comparative bone and dental identification, reconstructive identification and lesion identification. Comparative identification, the comparison of ante- and post-mortem imaging data, can be performed on both teeth and bones. Reconstructive identification, a considerable challenge for the radiologist, identifies the deceased by determining sex, geographical origin, stature and age at death. Lesion identification combines virtual autopsy and virtual anthropology. MSCT can be useful in palaeopathology, seeking arthropathy, infection, oral pathology, trauma, tumours, haematological disorders, stress indicators or occupational stress in bones and teeth. We examine some of the possibilities offered by this new radiological subspeciality that adds a new dimension to the work of the forensic radiologist. A multidisciplinary approach is crucial and involves communication and data exchange between radiologists, forensic pathologists, anthropologists and radiographers.

Postmortem whole-body MRI in traumatic causes of death

OBJECTIVE

The aim of this study was to determine the sensitivity and specificity of postmortem whole-body MRI for typical injuries resulting from traumatic causes of death.

MATERIALS AND METHODS

Forty cases of accidental death were evaluated with postmortem whole-body MRI. Imaging was conducted according to a standard protocol, and each examination had an average duration of 90 minutes. The imaging findings were correlated with the autopsy findings, which served as the reference standard.

RESULTS

MRI showed the main pathologic process leading to death in 39 of the 40 cases. The sensitivity of postmortem MRI ranged from 100% (pneumothorax) to 40% (fractures of the upper extremities). In general, MRI had a high level of performance for depicting soft-tissue lesions, such as subcutaneous hematoma (e.g., galeal hematoma with a sensitivity 95%). The sensitivity of MRI was remarkably lower for lesions of the upper abdominal organs (liver, 80%; spleen, 50%; pancreas, 60%; kidneys, 66%).

CONCLUSION

Postmortem whole-body MRI had overall good performance for depicting traumatic findings in corpses and therefore may serve an important role as an adjunct to classic autopsy for the forensic examination of cases of traumatic cause of death. However, the reduced sensitivity of postmortem MRI for lacerations of the upper abdominal organs and the observed superimposition of antemortem findings and postmortem findings (e.g., in the pulmonary tissue) in this retrospective study suggest that whole-body postmortem MRI not be recommended as a replacement for classic autopsy.

Are frontal sinuses useful indicators of sex?

Accurate sex prediction of skeletonised human remains excludes one-half of the population, enabling a more focussed search of missing persons' files. The skull is useful in sex assessment of skeletonised remains; however, its fragmentation precludes the use of all conventional craniofacial markers. The frontal bone may be recovered intact in fragmented remains and the sinuses therein may be useful in sex differentiation. A total of 100 paranasal sinus view radiographs of 50 males and females each were evaluated for potential differences in frontal sinus configuration following the methods of Yoshino et al. (Forensic Sci Int 1987; 34:289-99.) and Tang et al. (Forensic Sci Int 2009; 183:104.e1-3.). Data were assessed through univariate and multivariate statistics. The univariate Mann-Whitney U-test revealed statistically insignificant sexual dimorphism (p > 0.05) for the frontal sinuses. Moreover, multivariate logistic regression equations allowed correct sex identification in 60% of cases only. Possible reasons for the low sexual dimorphism may be frontal sinus' high inter-individual variability; also, existing techniques that employ frontal sinus classification systems may lead to a loss of information when features that require visual observation are grouped and assigned class numbers. The results herein suggest that frontal sinuses may have limited application as the sole predictor of sex.

Identification using frontal sinus by three-dimensional reconstruction from computed tomography

Radiographs and computed tomography (CT) images have been increasingly applied and accepted in forensic sciences. Along with radiographs and CT images, the frontal sinus is often used for the individual identification because of its unique and unchangeable characteristics. The purpose of this study is to define the usefulness of three-dimensional (3-D) images of the frontal sinus for identification. CT images from 119 Korean cadavers were built up for 3-D reconstruction and surveyed with 15 measurements. The total volume of the sinus, some nonmetric characteristics, and the bilateral asymmetry index in men differed significantly from those in women (p < 0.05). The digit codes, six sections and 10-digit number, were almost able to accurately identify individuals (98%). This study showed a statistical difference between the sexes and classified the fused and prominent middle sinuses for the first time. This proposed method for identification is more accurate than those used in other studies.

Human identification based on cranial computed tomography scan: a case report

Today, there is increasing use of CT scanning on a clinical basis, aiding in the diagnosis of diseases or injuries. This exam also provides important information that allows identification of individuals. This paper reports the use of a CT scan on the skull, taken when the victim was alive, for the positive identification of a victim of a traffic accident in which the fingerprint analysis was impossible. The authors emphasize that the CT scan is a tool primarily used in clinical diagnosis and may contribute significantly to forensic purpose, allowing the exploration of virtual corpses before the classic autopsy. The use of CT scans might increase the quantity and quality of information involved in the death of the person examined.

A state-of-the-art pipeline for postmortem CT and MRI visualization: from data acquisition to interactive image interpretation at autopsy

The importance of autopsy procedures leading to the establishment of the cause of death is well-known. A recent addition to the autopsy work flow is the possibility of conducting postmortem imaging, in its 3D version also called virtual autopsy (VA), using multidetector computed tomography (MDCT) or magnetic resonance imagining (MRI) data from scans of cadavers displayed with direct volume rendering (DVR) 3D techniques. The use of the data and their workflow are presented. Data acquisition was performed and high quality data-sets with submillimeter precision were acquired. New data acquisition techniques such as dual-energy CT (DECT) and quantitative MRI, then were implemented and provided additional information. Particular findings hardly visualized in conventional autopsy can rather easy be seen at the full body CT, such as air distribution, e.g. pneumothorax, pneumopericardium, air embolism, and wound channels. MRI shows natural deaths such as myocardial infarctions. Interactive visualization of these 3D data-sets can provide valuable insight into the corpses and enables non-invasive diagnostic procedures. In postmortem CT imaging, not being limited by a patient depending radiation dose limit the data-sets can, however, be generated with such a high resolution that they become difficult to handle in today's archive retrieval and interactive visualization systems, specifically in the case of full body scans. To take full advantage of these new technologies the postmortem workflow needs to be tailored to the demands and opportunities that the new technologies allow.

Radiologic identification of disaster victims: a simple and reliable method using CT of the paranasal sinuses

OBJECTIVE

To assess the reliability of radiologic identification using visual comparison of ante and post mortem paranasal sinus computed tomography (CT).

SUBJECTS AND METHODS

The study was approved by the responsible justice department and university ethics committee. Four blinded readers with varying radiological experience separately compared 100 post mortem to 25 ante mortem head CTs with the goal to identify as many matching pairs as possible (out of 23 possible matches). Sensitivity, specificity, positive and negative predictive values were calculated for all readers. The chi-square test was applied to establish if there was significant difference in sensitivity between radiologists and non-radiologists.

RESULTS

For all readers, sensitivity was 83.7%, specificity was 100.0%, negative predictive value (NPV) was 95.4%, positive predictive value (PPV) was 100.0%, and accuracy was 96.3%. For radiologists, sensitivity was 97.8%, NPV was 99.4%, and accuracy was 99.5%. For non-radiologists, average sensitivity was 69.6%, negative predictive value (NPV) was 91.7%, and accuracy was 93.0%. Radiologists achieved a significantly higher sensitivity (p < 0.01) than non-radiologists.

CONCLUSIONS

Visual comparison of ante mortem and post mortem CT of the head is a robust and reliable method for identifying unknown decedents, particularly in regard to positive matches. The sensitivity and NPV of the method depend on the reader's experience.

Contribution of postmortem multidetector CT scanning to identification of the deceased in a mass disaster: Experience gained from the 2009 Victorian bushfires

CT scanning of the deceased is an established technique performed on all individuals admitted to VIFM over the last 5 years. It is used primarily to assist pathologists in determining cause and manner of death but is also invaluable for identification of unknown deceased individuals where traditional methods are not possible. Based on this experience, CT scanning was incorporated into phase 2 of the Institute's DVI process for the 2009 Victorian bushfires. All deceased individuals and fragmented remains admitted to the mortuary were CT scanned in their body bags using established protocols. Images were reviewed by 2 teams of 2 radiologists experienced in forensic imaging and the findings transcribed onto a data sheet constructed specifically for the DVI exercise. The contents of 255 body bags were examined in the 28 days following the fires. 164 missing persons were included in the DVI process with 163 deceased individuals eventually identified. CT contributed to this identification in 161 persons. In 2 cases, radiologists were unable to recognize commingled remains. CT was utilized in the initial triage of each bag's contents. If radiological evaluation determined that bodies were incomplete then this information was provided to search teams who revisited the scenes of death. CT was helpful in differentiation of human from non-human remains in 8 bags, recognition of human/animal commingling in 10 bags and human commingling in 6 bags. In 61% of cases gender was able to be determined on CT using a novel technique of genitalia detection and in all but 2 cases this was correct. Age range was able to be determined on CT in 94% with an accuracy of 76%. Specific identification features detected on CT included the presence of disease (14 disease entities in 13 cases), medical devices (26 devices in 19 cases) and 274 everyday metallic items associated with the remains of 135 individuals. CT scanning provided useful information prior to autopsy by flagging likely findings including the presence of non-human remains, at the time of autopsy by assisting in the localization of identifying features in heavily disfigured bodies, and after autopsy by retrospective review of images for clarification of issues that arose at the time of pathologist case review. In view of the success of CT scanning in this mass disaster, DVI administrators should explore the incorporation of CT services into their disaster plans.

Evaluation of frontal sinus and skull measurements using spiral CT scanning: an aid in unknown person identification

The present study was undertaken to test a simple system for the identification of unknown bodies using spiral CT images of frontal sinus and other skull measurements among selected Iraqi sample. Ninety patients (45 males and 45 females) with age range from 20 to 49 years were selected in this study. Three features and two groups of measurements of frontal sinus and three skull dimensions were obtained from the CT images. Three basic features were F (presence or absence of frontal sinus), S (septum) and S (scalloping). Measurements selected for the study were frontal sinus width, height and anteroposterior length. In addition to measurements of total width, the distance between the highest points of the two sinuses, the distance between the highest points of each sinus to its maximum lateral limit. Skull measurements included; maximum skull length, prostio-bregmatic height and maximum skull width. All data were subjected to a descriptive and discriminative analysis using the SPSS (Version 17.0). The pre-post comparison (number of discordant items) resulted in 95% accurately predicted perfect match for intra-examiner calibration and 90% accurately predicted perfect match for inter-examiners calibration and the result for one discordant item was 5% for intra-examiner calibration and 10% for inter-examiners calibration. The discriminative analysis showed that the ability of the frontal sinus to identify gender was 76.9%, adding the skull measurements to the frontal sinus measurements gave a higher overall classification accuracy for gender (85.9%). Frontal sinus measurements are valuable method in differentiating gender. Adding skull measurements to the frontal sinus measurements can significantly improve accuracy of gender determination using discriminant analysis. CT based films can provide valuable and precise measurements not only for frontal sinus but even for the whole skull that cannot be approached by other means.

A new digital method for the objective comparison of frontal sinuses for identification

Use of the frontal sinuses for identification requires an objective method of comparison to meet Daubert standards. Christensen's application of Elliptical Fourier Analysis and Likelihood Ratios seems to be a viable solution for this problem. The proposed method draws upon this work and attempts to simplify its application. Variation between pairs of digitized sinus tracings was quantified by summing the difference between corresponding measurements taken from a fixed origin to the outer edge of the sinus outlines using Adobe Photoshop CS2. Same-skull and different-skull pairs were used to develop reference distributions from which the probability of unknown pairs coming from the same or a different individual was estimated. Error rates of 0% were achieved. Resulting correlation coefficients demonstrated inter-rater and test-retest reliability. Further refinement of the reference distributions and more rigorous testing of error rates should make this technique applicable to casework.

Assessing forensic applications of the frontal sinus in a Chinese Han population

The frontal sinus is an important tool of personal identification. To assess the forensic applications of the frontal sinus patterns in a Chinese Han population, 198 individuals were analyzed. 165 individuals who have the frontal sinus were observed in this population, and 12 parameters of the frontal sinus were observed according to Yoshino's method. The same combined code was found in three persons from our samples. The unilateral frontal sinus scalloped with one arcade has few parameters applied to personal identification, and shows the poorer discrimination power. These parameters showed better discrimination power in our population, and could be applied to personal identification.

The forensic importance of frontal sinus radiographs

The identification of unidentified human remains through the comparison of antemortem and postmortem radiographs has found wide acceptance in recent years. Reported here is the forensic case of an unidentified adult male who had died as the result of a traffic accident, after which the body was identified by matching images of ante- and postmortem radiographs of the frontal sinus. A general discussion on identification using frontal sinus radiographs is presented, highlighting the reliability of this method, in reference to the uniqueness of the frontal sinus in humans. However, it also notes a few difficulties, especially in reference to the X-ray technique in cases where antemortem radiographs are available and a potentially larger number of anatomical, pathological or traumatic features are present. The comparison of frontal sinus outlines is recommended when it may become necessary to provide quantitative substantiation for forensic identification based on these structures.