Journal of Indian Academy of Oral Medicine and Radiology

REVIEW ARTICLE
Year
: 2015  |  Volume : 27  |  Issue : 3  |  Page : 416--422

Forensic radiology: An emerging tool in identification


Raghav Kumar, Appaji Athota, Trisha Rastogi, Sunil Kumar Karumuri 
 Department of Oral Medicine and Radiology, DJ College of Dental Sciences and Research, Modinagar, Uttar Pradesh, India

Correspondence Address:
Sunil Kumar Karumuri
Department of Oral Medicine and Radiology, DJ College of Dental Sciences and Research, Modinagar - 201 204, Uttar Pradesh
India

Abstract

In any mass disaster condition, identification of the person is most important. For this purpose, the forensic investigators use different methods for identifying the dead. They consider skeletal remains of the dead as the initial step in identification. Radiographs carry great evidence to act as antemortem records and also assist in identifying the person, age, gender, race, etc. Forensic dentistry is also emerging as a new branch in forensics. So, the forensic dentist must be aware of different techniques, developments, and resources to incorporate the technology in order to achieve success in human identification. So, our aim of the present review is to focus on different radiological techniques and new developments available for successful identification of the dead.



How to cite this article:
Kumar R, Athota A, Rastogi T, Karumuri SK. Forensic radiology: An emerging tool in identification.J Indian Acad Oral Med Radiol 2015;27:416-422


How to cite this URL:
Kumar R, Athota A, Rastogi T, Karumuri SK. Forensic radiology: An emerging tool in identification. J Indian Acad Oral Med Radiol [serial online] 2015 [cited 2019 Nov 13 ];27:416-422
Available from: http://www.jiaomr.in/text.asp?2015/27/3/416/170478


Full Text

 Introduction



In spite of the fast growing technology and modern advancements, human race is still facing problems due to natural disasters (earthquakes, tsunamis), medical breakthroughs, crime, and violence, taking many lives. Very little can be done to repair such damage. The main motto of identifying the dead is for personal, social, and legal purposes. Forensic science deals with the identification of the dead using numerous techniques. Forensic odontology has a lot of scope in human identification. Methods like rugoscopy, bite marks, palatal rugae, photographs, lip prints, etc. are used for identifying the individuals. [1]

Most of these methods rely largely on the preservation of soft-tissue components of the body in question and cannot be used if the remains are burnt, decomposed, mutilated, and destroyed. In the human body, teeth and facial bones are resilient and withstand the decompositional/destructional forces well even under extreme forces and/or temperature variations. As radiographs are able to capture their distinct anatomical features, they become an invaluable tool in forensic sciences. Radiographic identification has long been in use and the technique is efficient, comparatively easy, records can be obtained in both living and dead, and is economical than DNA technology. [2] So, expertise knowledge and proper application of maxillofacial radiological techniques has a valuable role in forensic identification and solving medico-legal cases. [3],[4] Now-a-days, forensic radiology is evolving as a branch of forensic dentistry, in which radiographs play a vital role in identification of the dead. In this review, the authors attempt to sensitize the readers regarding the scope of oral radiology in forensic science.

 Historical Milestones in Forensic Radiology



1895 - Discovery of X-rays by Wilhelm Conrad Roentgen.1896 - Prof. Arthur Schuster used X-rays to visualize the lead bullets in the head of a dead person. [5] In October 1898 issue of the American X-ray Journal, Dr. Fovau d'Courmelles wrote, "Knowing the existence of a fracture in a person who has been burned or mutilated beyond recognition, we can hope to identify him by the X-ray." [6] In 1921, Schuller compared the radiographs of the frontal sinuses. [7] In 1927, Culbert and Law described the complete radiological identification of the skull by using pneumatic cells of the sinuses. [7] In 1991, Happonen et al. recommended the use of orthopantomography in identification, which enables visualization of the jaws and related structures as a single radiograph. In the same year, Haerting et al. stated that panoramic dental radiography is the only regularly updated and "truly reliable identification card" for comparison radiography.Radiology was also applied in the identification of celebrities like Theodore Roosevelt and Adolph Hitler.Forensic radiologists had been using the traditional methods for capturing the images. With the advancement of technology, newer armamentarium like NOMAD (portable hand held X-ray generating device manufactured by Aribex, Charlotte, North Carolina, USA), computed tomography (CT), cone beam computed tomography (CBCT), multidetector CT (MDCT), and magnetic resonance imaging (MRI) are gradually replacing the traditional ones.

 Forensic Identification



Identification is a process which involves different procedures and techniques to confirm an object or person in both living and deceased conditions. [5] The conditions that demand identification are:

Medico-legal cases.Natural disasters like tsunamis, earthquakes, explosions, etc.For confirming death in monetary issues.Religious and social purposes.Following are the various methods of identifying the person using dental/oral radiographs as a main tool.

 Dental Identification



When a body of a person is available in a burned, decomposed state, any dental remains of the person, such as restorations, teeth present, any missing teeth, and prosthesis, play a major role in identifying the dead. Teeth (max. 1000°C) and dental restorations (acryclic 540°C, gold and amalgam 870°C, porcelain 1100°C) are resistant to destruction by fire and, therefore, useful in identification. Dental identification is based on comparison and exclusion of the radiographs exposed prior to death (antemortem) to those exposed after death (postmortem). This data is assessed based on factors like teeth present, teeth missing, crown structure, root morphology, pulp anatomy, occlusion, wear and tear of tooth structure, pathology, different treatment procedures, etc. Proper comparison and interpretation of these factors leads to successful identification. [3],[8]

The American Board of Forensic Odontology (1986) [9] has given the following four situations regardless of the factors and methods used in comparing ante- and postmortem radiographs:

Positive identification: Comparable items are sufficiently distinct in the ante- and postmortem databases; no major differences are observed.Possible identification: Commonalities exist among the comparable items in the ante- and postmortem databases, but enough information is missing from either source to prevent the establishment of a positive identification.Insufficient identification evidence: Insufficient supportive evidence is available for comparison and definitive identification, but the suspected identity of the decedent cannot be ruled out. The identification is then deemed inconclusive.Exclusion: Unexplainable discrepancies exist among comparable items in the ante- and postmortem databases.

 Anatomical Identification



Schuller [10] had given a classification using frontal sinus radiography taken in the forehead-nose position for assessing sex and race. He proposed seven characteristics of radiographs:

Septum and its deviation.Upper border.Partial septum.Ethmoidal and supraorbital extensions.Height from planum.Total breadth.Position of sinus midline.Some typical features of frontal sinus morphology are its highly variable nature even in genetically identical twins, which was proven by Christensen, [11] stable structure in the adult period, and its resilient structure with strong bony walls, which protects them from damage and decomposition. [12] It has high fracture resistance; a minimum of 800-1600 foot pounds is required to fracture the frontal sinus. It is helpful in identifying the persons who are victims of high-impact accidents or gunshot wounds. [13] Cox et al. reported in 2009 that superimposition of an antemortem radiograph of the suspected victim's frontal sinuses over a postmortem radiograph helped to make correct identification in 100% of cases. [11]

 Dental Profiling



It is a way to recreate the deceased person's profile prior to death based on clinical and radiological data available. Dental radiology helps in assessing the angulation of anterior teeth that are lost after postmortem, and also examination of sockets aids in number and alignment of teeth. [14] Ante- and postmortem radiographic comparison also helps in dental profiling. Unusual dental anatomy like mandibular premolars which show high variations in the pattern and number of grooves and cusps helps in comparison. [15] Radiovisiography allows spatial resolution of the images and helps in the precise analysis of the structures on ante- and postmortem images. It also reduces the number of new exposures, record keeping, and comparison of these images is made easy. [15] The information provided by the antemortem CT image can be utilized in fabrication of the postmortem profile, so that the craniometric points can be accurately located and measured. [16]

 Medico-legal Cases



Forensic radiology helps in determining the cause of death (accident or intention). The radiographs can interpret the point and direction of impact. Strangulation is indicated by broken thyroid cornua or hyoid bone. Metabolic abnormalities, infections and dietary deficiencies, and bleeding disorders may leave signs on the bones that can be seen radiographically. Radiographs provide evidence of foreign bodies or bullets present in soft tissues due to mass disasters. CT and CBCT can be used in assessing the degree of wound in cases of skull injury. [17],[18]

 Racial and Gender Determination



Forensic dentists along with forensic anthropologists analyze the calcified structures of the body like bones and teeth. This aids in determining the race and gender of the deceased persons. [19],[20] Important features in identifying the race and gender are tabulated in [Table 1] and [Table 2], respectively.{Table 1}{Table 2}

 Cranio-facial Reconstruction



Cranio-facial reconstruction (CFR) is considered when no ante- and postmortem data is available of the unknown person. It is widely used in anthropology, medicine, and forensic dentistry. The progress made in computer science and computer software programs on medical imaging techniques allows the superimposition of known and unknown skull radiographs. As the clinical use of cross-sectional imaging methods such as CT and MR has increased, many forensic dentists also have begun to evaluate these technologies as potential tools in CFR. The use of CT has evolved into the "virtual autopsy" (or "virtopsy") concept. This involves a complete forensic investigation using CT and MR imaging combined with 3D reconstruction and postprocessing. The images are taken before the conventional autopsy begins. New MDCT scanners increase the volume acquisition of data sets along the same axis, which may be measured in two and three dimensions. The resulting reconstruction closely resembles standard autopsy. [21],[22]

MDCT is effective in evaluating projectile entry and exit locations, path, and associated tissue injury to characterize penetrating and perforating injuries. The method has limitations compared with clinical application, such as the inability to use contrast to better distinguish among soft tissues and vascular structures. MDCT is usually performed in the supine position, which can affect projectile tracks and organ shifts. However, the technique is noninvasive and potentially can enhance investigations. [23]

 Digital Radiography in Forensic Odontology



Digital radiography when used along with dental matching software fastens the forensic victim's identification. Also, digital radiography reduces the exposure times by requiring 90% less radiation than that required to expose a standard type D film radiograph and 50% less radiation than that required in exposure of type E film radiographs.

 Digital Photography



The various digital photography equipment include through-the-lens (TTL), light-metering, and single-lens reflex (SLR). The Scientific Working Group on Imaging Technology (SWGIT) provides the imaging guidelines for forensic radiologist with information regarding the limitations and parameters imposed by the judicial system for manipulation of digital photographic evidence.

 Age Estimation



Estimating age is the most important prerequisite for identification of the dead. Historically, the first age assessment using teeth was done by Edwin Saunders in 1837 in a paper titled "Teeth A Test of Age" that was presented to the English parliament. [24] Age estimation can be done by various factors like:

Jaw bones.Tooth germs.Process of mineralization.Stages of crown development, completion and their eruption into oral cavity.Volume of pulp chamber.Third molar development and eruption pattern.Root morphology.Age estimation methods may be classified as: [25]

Age estimation methods for the forming dentition.Age estimation methods for the adult dentition.Methods of age estimation may also be classified based on the techniques used:

Clinical or visual examination.Radiographic examination.Histological and biochemical methods.There are different techniques and methods of age estimation given by different authors. Here, we discuss some of the important methods utilizing radiography.

1. Schour and Masseler (1941): [26] Their work is based on the studies done by Logan and Kronfield (1933). Schour and Masseler proposed 21 chronological steps from 4 months to 21 years of age [Figure 1]. They did not propose any method for males and females.{Figure 1}

2. Demirjian et al. (1973): [27] They have developed a system for estimating the chronologic age based on eight stages of tooth development as follows:

A: Cusp tips mineralized, but not yet closed.

B: Mineralized cusps are united, so the mature coronal morphology is well defined.

C: Crown is about half formed, pulp chamber is evident, and dentin deposition is occurring.

D: Crown formation is complete up to dentino-enamel junction; pulp chamber has a trapezoid form.

E: Formation of inter-radicular bifurcation has begun; root length is less than crown length.

F 1: Root length is at least as great as crown length; root has funnel-shaped ending.

F 2: Root length is at least twice the crown length; still the root has funnel-shaped ending.

G: Root walls are parallel, but apices remain open.

G 1: Root walls are parallel, but apices are not entirely closed. Periodontal ligament (PDL) space at apical ending is ≥1.0 mm.

H: Apical ends of roots are completely closed and PDL has uniform width around the root.

Willems, [15] in the year 2001, modified this method. He directly calculated the scores for expressing age in years and also eliminated the conversion step from maturity index to dental age, making it easier and simple.

3. Nolla's technique: Mineralization patterns of permanent teeth were used in 10 stages for assessing the age. Maxillary and mandibular teeth were used with or without the presence of third molar.

4. Kvaal method: This method is based on the ratio of pulp to tooth. Six maxillary and mandibular teeth were used. The formula given by Kvaal et al. is:

Age = 129.8 - (316.4 × M) (6.8 × (W − L))

where in the following parameters are measured and calculated: Maximum tooth length, pulp length, root length on mesial side of teeth, pulp width at level a [cementoenamel junction (CEJ)], level c (midroot level), and level b (midpoint of c and a), root width at level a, level c, and level b, root length/tooth length ratio (T), pulp length/tooth length ratio (R), pulp length/root length ratio (P), pulp width/root width ratio at level a (A), pulp width/root width ratio at level b (B), pulp width/root width ratio at level c (C), mean values of all ratios (M), mean value of width ratios from levels b and c (W), mean value of length ratios P and R (L), and difference between W and L (W - L).

5. Van Heerden method: [28] This method uses third molar for age assessment in adults. He studied mesial root of third molar in five stages [Table 3] using panoramic radiographs. Males and females were studied independently with no significant differences between them.{Table 3}

 Other Uses of Forensic Radiography



As early as the 19 th century, the French customs service was using fluoroscopy to image contraband in smugglers. Imaging may detect packages in body cavities; advanced techniques, such as CT, have proven more useful in detecting modern packaging. [29] Smuggled drugs may be incidental findings when patients who have been assaulted or victims of motor vehicle accidents are imaged. Imaging has also been used to detect other ingested materials and to identify nonballistic material in the body, such as knife blades and needles. Radiographic methods also have been used to detect art forgeries. Advanced imaging techniques not only have improved forensic investigation, but also have provided more powerful and informative exhibits for jurors. [30]

Neuroimaging may be used as evidence to support mental health expert testimony. A defense expert used a CT scan of John W. Hinckley's brain to support the notion that he suffered from schizophrenia when he attempted to assassinate former president Ronald Regan. Functional neuroimaging techniques such as positron emission tomography can demonstrate blood flow changes that are associated with changes in neural activity. Functional neuroimaging evidence has been used in criminal cases to support insanity defenses, claims that a defendant was incompetent to stand trial, or for pleas of leniency in sentencing; the imaging information is an adjunct to behavioral and clinical data. [31]

A new revolution is using diagnostic imaging modalities like dual X-ray absorptiometry (DEXA) for measuring bone mineral density (BMD) and bone mineral content (BMC) in forensic identification. Measuring the bone density has many uses like calculating the body mass index, bone length, composition, bone structure, and neutral density in various body parts. The use of DEXA in measuring bone density is well established in the field of diagnostic imaging for pathologies like osteoporosis, osteomalacia, etc. A lot of field research and studies are conducted to apply this newer modality in the field of forensic anthropology and for identification of skeletal remains. [32],[33]

 Conclusion



Forensic radiology has humble and ancient origins. Ancient writings have provided evidence that medical principles have been applied to legal issues for thousands of years. It was not long after Roentgen discovered "a new kind of ray" that innovative forensic scientists established its value in forensic science. Professor Roentgen furnished the tool; the imagination and diligence of many scientists to follow resulted in X-ray's myriad uses. Radiologic imaging is better defined as the practice that lies at the many interfaces of medicine and law. Radiologic imaging plays a vital role at many of those intersections, from the identification of dead to the authentication of priceless art.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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