The use of computed tomography in determining developmental changes, anomalies, and trauma of the thyroid cartilage

Diagnostic accuracy of post-mortem computed tomography for fractures of the hyoid-larynx complex

Post-mortem computed tomography (PMCT) is routinely used at many forensic institutions to guide the following autopsy and is especially useful for diagnosing fractures. This systematic review aims to investigate the sensitivity and specificity of a PMCT scan in fracture diagnosis of the hyoid-larynx complex (HLC) compared to traditional autopsy in cases involving traumatic neck injuries. We searched PubMed, SCOPUS and Web of Science and included papers with cases n ≥ 3 published between January 2000 and April 2023 reporting on PMCT and autopsy findings of fractures of the HLC. The search provided 259 results of which 10 were included. Overall sensitivity and specificity were 0.70 [0.59; 0.79] and 0.92 [0.80; 0.97] for hyoid bone fractures and 0.80 [0.62; 0.91] and 0.76 [0.63; 0.85] for the thyroid cartilage. The results show great variation, and a large range between studies. These results indicate that PMCT cannot replace autopsy in cases with HLC fractures. Future larger prospective studies are needed, examining fracture details, scan protocols and different slice thicknesses using uniform reporting.

Triticeal cartilage: a meta-analysis of prevalence and morphologic evaluation

PURPOSE

The triticeal cartilage, situated within the lateral thyrohyoid membrane, remains elusive in function yet crucial in clinical contexts. Composed of hyaline cartilage, it is prone to ossification, potentially leading to diagnostic challenges such as misidentification with atherosclerosis or fractures.

METHODS

This study, aiming to establish its prevalence and highlight clinical relevance, conducted a systematic review across several electronic databases such as Medline, PUBMED, Scopus, Google Scholar, Web of Science, SpringerLink and Sciencedirect using keywords "triticeal cartilage", "triticeous cartilage" or "cartilago triticea". An assurance tool for anatomical investigations was used to assess the quality of the methodology (AQUA). A random effects model was utilized to determine the pooled prevalence.

RESULTS

The true prevalence of triticeal cartilage was found to be variable, with an overall pooled proportion of 43% while crude prevalence were 50.6%. Its crude prevalence was notably higher in women compared to men, in contrary true prevalence was higher in men, posing sex-related disparities. It was mostly seen bilaterally. When the morphologic characteristics of the cartilage were evaluated, classification differences were observed in terms of shape, with a mean length of 5.48 mm, a mean width of 3.04 mm and a mean weight of 62.32 mg. The vertebral level at which the TC was located was mostly C4. The degree of calcification of the cartilage was most commonly mild.

CONCLUSION

In conclusion, triticeal cartilage holds significant clinical importance, necessitating vigilance during diagnostic evaluations and surgical approaches. Further studies are imperative to elucidate its function comprehensively and refine diagnostic strategies, ensuring optimal patient care in neck-related pathologies.

Postnatal changes in thyroid cartilage shape and cartilage matrix composition are not synchronized in Mus musculus

The study was conducted to quantify laryngeal cartilage matrix composition and to investigate its relationship with cartilage shape in a mouse model. A sample of 30 mice (CD-1 mouse, Mus musculus) from five age groups (postnatal Days 2, 21, 90, 365, and 720) were used. Three-dimensional mouse laryngeal thyroid cartilage reconstructions were generated from contrast-enhanced micro-computed tomography (CT) image stacks. Cartilage matrix composition was estimated as Hounsfield units (HU). HU were determined by overlaying 3D reconstructions as masks on micro-CT image stacks and then measuring the attenuation. Cartilage shape was quantified with landmarks placed on the surface of the thyroid cartilage. Shape differences between the five age groups were analyzed using geometric morphometrics and multiparametric analysis of landmarks. The relationship between HU and shape was investigated with correlational analyses. Among five age groups, HU became higher in older animals. The shape of the thyroid cartilage changes with age throughout the entire life of a mouse. The changes in shape were not synchronized with changes in cartilage matrix composition. The thyroid cartilage of young and old M. musculus larynx showed a homogenous mineralization pattern. High-resolution contrast-enhanced micro-CT imaging makes the mouse larynx accessible for analysis of genetic and environmental factors affecting shape and matrix composition.

Laryngeal cartilage calcifications on lateral cephalometric radiographs

The aim of this study was to determine the influence of age and gender on the incidence of calcification in laryngeal cartilage diagnosed on lateral cephalometric radiographs routinely taken for orthodontic diagnosis. The lateral cephalometric radiographs of 957 patients who met the study criteria were analyzed from among the 1000 lateral radiographs originally collected. The images were evaluated independently by two investigators. Given the dichotomous dependent variable (calcification or no calcification), a mixed logistic regression model was used to test how age and gender affected calcification. The effect of age and gender reliably determined the likelihood of laryngeal cartilage calcification. The greatest differences in the degree of calcification by gender were found at ages 20-25 years. The degree of calcification increased with age, reaching 100% in women at age 30 and in men at age 50. In women, the degree of calcification was higher than in men from the age of 13 years and levelled off at the age of 50 years. The interrater agreement was strong k = 0.97, z = 30.0, p < .001. Calcification can be detected by orthodontists trained in lateral cephalogram analysis and can be used as a screening or diagnostic tool to detect calcified areas in the larynx.

Cartilage Tissue in Forensic Science—State of the Art and Future Research Directions

Cartilage tissue performs many functions in the human body. The diseases and injuries affecting it are prevalent due to its slow regeneration rate. However, cartilage tissue is exceptionally important for its auspicious use in forensic medicine due to its slow postmortem degradation rate. The presented review summarizes the latest research on cartilage tissues and their current and potential applications in forensic science. It also describes the most important studies on using cartilage and its microscopic and macroscopic analyses to estimate the deceased age and determine postmortem interval (PMI) values and the crime weapon. Additionally, the review describes attempts to isolate DNA from cartilage tissue for individual identification. The review also mentions recent, less abundant studies on the cartilage in forensic toxicology and genetics. It points out further directions and prospects for research development on cartilage tissue and its promising use in forensic medicine

Comparison of findings identified at traditional invasive autopsy and postmortem computed tomography in suicidal hangings

Cases of suicidal hanging are a common death referred for medico-legal autopsy throughout the world. Although some advocate using postmortem computed tomography (PMCT) without traditional invasive autopsy (TIA) to investigate such deaths, others reject this approach. There is currently limited evidence to guide practice. In this context, the TIA reports and PMCT images of 50 cases of suspected suicidal hanging during an 11-month period were reviewed. The reviewers were blinded to the findings of the other modality. A Cohen’s Kappa coefficient (K) was calculated to assess agreement between TIA and PMCT across a range of pertinent findings. This analysis demonstrated perfect agreement for identification of a ligature (K = 1.00) and a strong level of agreement for identification of a ligature suspension point (K = 0.832) but only a minimal level of agreement for overall ligature mark (K = 0.223). PMCT demonstrated a weak level of agreement for fractures of hyoid bone (K = 0.555) and thyroid cartilage (K = 0.538). Three probable fractures not identified at TIA were identified on PMCT. TIA was shown to be superior in the identification of intramuscular and laryngeal fracture–related haemorrhage/bruising whereas PMCT was superior to TIA in identifying body gas deposition. There was overall good correlation between the natural disease and trauma identified elsewhere in the body during the TIA and PMCT. The study demonstrates that PMCT can assist the investigation of suspected suicidal hangings. However, the accuracy of many findings is limited, and if it is used as an alternative to the TIA, potentially pertinent findings, such as fractures of the laryngeal cartilages, could be missed.

Incidence and factor analysis of laryngohyoid fractures in hanging individuals-computed tomography study

OBJECTIVES

Although laryngohyoid fracture indicates the applied neck pressure and is an important finding in hanging individuals, the reported rate varies widely and its true incidence remains controversial. We used computed tomography (CT) studies to investigate the incidence of laryngohyoid fracture in hanging individuals and identify factors contributing to such fractures.

METHODS

Considered for inclusion in this study were 107 attempted or successful hanging individuals subjected to CT studies between 2005 and 2019. After excluding 19 whose images were inadequate for evaluation, 88 subjects were included. Body suspension was complete in 20, partial in 49, and unknown in 19; 54 (61.4%) individuals died. Two radiologists performed image analysis and recorded the presence and site of laryngohyoid fractures. Multiple logistic regression analysis was used for factor analysis of laryngohyoid fractures; it included the gender, the age (< or ≧ 40 years), the type of suspension (complete or incomplete), and the outcome (death or survival).

RESULTS

Of the 88 subjects, 35 (39.8%) presented with laryngohyoid fractures on CT images; the superior horn of the thyroid cartilage was fractured in 32 (91.4%) of the 35. Age was the only factor significantly related to laryngohyoid fracture (odds ratio = 2.85, 95% confidence interval = 1.08-7.52).

CONCLUSIONS

In hanging individuals, the incidence of laryngohyoid fracture on CT images was 39.8%. The superior horn of the thyroid cartilage was the most frequent fracture site.

KEY POINTS

• The incidence of laryngohyoid fracture on CT images of hanging individuals was almost 40%; the superior horn of the thyroid cartilage was the most frequent fracture site. • In older hanging individuals, attention must be paid to laryngohyoid fractures on CT images.

Anthropological analysis of trauma in throat bone and cartilage: A review

In their analysis of recovered human remains, forensic anthropologists encounter structures of the throat (hyoid bone, thyroid cartilage/bone, cricoid cartilage/bone) that may present evidence of trauma. The recent published literature provides guidelines for the detection and interpretation of fractures in these tissues. Such traumatic injury frequently is associated with victims of hanging and strangulation, but many other causes have been recognized. Although the hyoid is not always recovered in skeletonized remains, it can reveal evidence of perimortem trauma and must be interpreted appropriately.

Injuries of the isolated larynx-hyoid complex in post-mortem computed tomography (PMCT) and post-mortem fine preparation (PMFP) - a comparison of 54 forensic cases

Objectives

To assess the diagnostic accuracy (ACC) of post-mortem computed tomography (PMCT) for fractures of the isolated larynx-hyoid complex (LHC) in comparison to post-mortem fine preparation (PMFP).

Methods

This monocentric prospective study enclosed 54 LHCs that were extracted during autopsy, fixed in formalin, and underwent a PMCT scan (64-row multidetector CT, helical pitch). Two radiologists independently analyzed the LHC scans for image quality (IQ) and fractures (4-point Likert scales). A specialized forensic preparator dissected the specimens under the stereomicroscope. The PMFP results were standardized documented, and used as the standard of reference for the comparison to PMCT.

Results

The PMCT-IQ of 95% of the LHC images was rated as good or excellent. IQ was decreased by decay, incisions during autopsy, and separation of the hyoid from the cartilaginous components in 7, 3, and 12 specimens, respectively. PMFP detected 119 fractures in 34 LHCs (63.0%). PMCT identified 91 fractures in 32 specimens (59.3%). PMFP and PMCT significantly agreed concerning the location (Cohen’s κ = 0.762; p < 0.001) and the degree of dislocation (κ = 0.689; p < 0.001) of the fractures. Comparing PMCT to PMFP resulted in a sensitivity of 88.2%, a specificity of 90.0%, and an ACC of 88.9% for the LHC. The ACCs for the hyoid, thyroid, and cricoid were 94.4%, 87.0%, and 81.5%, respectively. PMCT procedure was significantly faster than PMFP (28.9 ± 4.1 min vs. 208.2 ± 32.5 min; p < 0,001).

Conclusions

PMCT can detect distinct injuries of the isolated LHC and may promptly confirm violence against the neck as cause of death. PMFP outmatches PMCT in the detection of decent injuries like tears of the cricoid cartilage.

Key Points

• Post-mortem computed tomography is able to assess fractures of the larynx-hyoid complex.

• Prospective monocentric in vitro study showed that post-mortem computed tomography of the larynx-hyoid complex is faster than post-mortem fine preparation.

• Post-mortem computed tomography can confirm violence against the neck as cause of death.

Using micro-computed tomography to examine the larynx in cases of suspected strangulation-a comparison of case findings and control images

The examination of strangulation is one of the most challenging causes of death diagnoses encountered in forensic pathology. The injuries are often subtle and difficult to detect, especially in cases that lack superficial marks. Fractures of the laryngeal skeleton are commonly regarded as evidence of strangulation but these can be too subtle to be detected during autopsy. Micro-CT is a novel imaging technique that achieves a spatial resolution 1 μm or less which lends itself to the examination of small and delicate structures such as the larynx. However, there is little information to date regarding the appearance of the larynx at this scale, thus complicating the interpretation of the micro-CT images. This study therefore uses micro-CT to examine ten larynges from strangulation deaths and to compare them to nineteen samples from donor individuals in order to distinguish between naturally occurring features and actual trauma. It was found that there are several features which mimic damage in the donor group. Using associated case information, initial trends and patterns of different strangulation methods were established.

Unilateral and bilateral agenesis of the upper thyroid horns - A morphometric analysis of the larynx

The agenesis of one or both upper thyroid horns (UTH) cannot be considered rare with an incidence ranging between 0.8-9.4%. Studies so far have mostly described frequencies, yet surveys on its morphology and traumatology are missing. It is unknown to what extent this anatomical variant impacts the overall symmetry of the larynx. For the trauma reconstruction after cervical trauma this knowledge is required as an asymmetric larynx can show a different fracture pattern. In this investigation, larynxes with unilateral (n=21)/bilateral (n=5) agenesis of the upper thyroid horn(s) and a control group with regular larynxes (n=23) were juxtaposed. Various measurements were taken after μ-CT scanning. In total 10 distances/angles for the thyroid cartilage and 8 for the cricoid cartilage were compared. Using intra-individual and matched pair comparisons the symmetry was assessed. The results of this investigation showed significant differences in the intra-individual and pairwise comparison for the opening angle and the length of the thyroid alae although the lateral inclination of the thyroid alae showed no significant difference. Combining these three parameters into one symmetry score, the comparison was not significant. This research demonstrates that neither unilateral nor bilateral agenesis of the UTH is related to a structural disbalance of the larynx. Thus, different fracture patterns or vulnerabilities are not to be expected.

Laryngeal anatomical variants and their impact on the diagnosis of mechanical asphyxias by neck pressure

The aims of this investigation were to determine the characteristics and prevalence of anatomical variants of the larynx apparatus and to evaluate the impact of these variants on the accurate diagnosis of laryngeal fractures. A population-based study was carried out, analyzing a series of 207 consecutive autopsied cases in the Institute of Legal Medicine of Galicia (Northwestern Spain). The prevalence of triticeal cartilage was 52.7% and that of agenesis of thyroid horns 10%. Calcification of the stylo-hyoid ligament accounted for 1.4%. We identified three new anatomical variants: the terminal segmentation of the thyroid horns (11.6%), ectopic superior thyroid horns (8%) and lateral thyrohyoid ossification (5.3%). These three names, based on anatomical criteria, are the author's proposal to solve the lack of uniformity in the designation of these variants. Agenesis of thyroid horns were related to the presence of ectopic superior thyroid horns in 93% of cases, either uni or bilateral. The combination of variants was present in 6.8% of the cases, being the terminal segmentation of the thyroid horns in association with triticeal cartilage the most frequent (3.8%). The probability of misdiagnosis due to the presence of anatomical variations in deaths by pressure on the neck was high in this population (71.5%). The prevalence of triticeal cartilage in more than half of the sample, determined an important rate of potential errors (46.4%), followed by the mistaken diagnoses induced by terminal segmentation of thyroid horns (7.3%) and by ectopic superior thyroid horns (6.3%). The likelihood of a misdiagnosed laryngeal fracture was greater if the thyroid cartilage was affected, with a higher proportion of false positives comparing to the hyoid bone (p<0.001). The higher frequency of thyroid fractures in neck pressure together with the prevalence and location of triticeal cartilage on the lower third of the lateral thyrohyoid ligament are the main reasons for these results. Further studies should be done with larger samples to expand epidemiological data and consolidate these results and their influence on the diagnosis of mechanical asphyxias.

The gas bubble sign-a reliable indicator of laryngeal fractures in hanging on post-mortem CT

OBJECTIVE

The purpose was to evaluate the presence of gas in the tissue adjacent to the laryngeal structures, "the gas bubble sign", in cases of hanging as a diagnostic indicator of neck trauma.

METHODS

In this study, post-mortem CT (PMCT) scans and autopsies of 35 victims of hanging were examined to reveal age-dependent changes, laryngeal fracture, fracture location and the presence of gas. A matched group with cardiac arrest or intoxication was used as controls (n = 35). An autopsy was performed in each case.

RESULTS

Incomplete suspension was the most common method in hanging. The thyroid horns (90.5%) were identified as the most vulnerable location for fractures. Laryngeal deformity and dislocation, which was only detected on PMCT, was observed in 57.1% and was concomitant with fractures in 83.3%. Laryngeal fractures are more common with advanced age (>40 years, 88.9%) and less common in younger subjects (<40 years, 29.4%). The gas bubble sign with regard to laryngeal fractures yielded a sensitivity of 79.2%, a positive predictive value of 95%, a specificity of 90.9%, a negative predictive value of 34.5% and an accuracy of 83%.

CONCLUSION

The complex evaluation of the larynx is profoundly supported by PMCT and the detection of the gas bubble sign as a diagnostic indicator of neck trauma. This relevant diagnostic finding might aid in not only post-mortem cases but also clinical cases, for patients who survive an assault to the neck. Advances in knowledge: (1) The gas bubble sign is a diagnostic indicator of neck trauma in not putrefied bodies. (2) PMCT supports evaluation of trauma to the neck in hanging tremendously. (3) The diagnostic finding of gas located at the laryngeal structures may not only aid in post-mortem cases but also clinical cases of people who survive an assault to the neck.

Age estimation by ossification of thyroid cartilage of Japanese males using Bayesian analysis of postmortem CT images

Many studies have reported that the degree of thyroid cartilage ossification correlates with age. However, its use in forensics has been limited by individual variation, tissue fragility, and observer subjectivity. We examined a new method for age estimation from the degree of ossification of thyroid cartilage using postmortem computed tomography (CT) and Bayesian analysis. The scoring of CT density values, ossification rate, and morphological changes was performed in 131 Japanese males (20-80years old), and an age estimation table was created and verified in 39 other Japanese males. We tried two types of prior probability; one was males undergoing postmortem CT imaging at our institute, and the other was the age composition of the male population in Japan. The differences in percentage in each age group were observed, especially in the ninth decade, but they were not large enough to change the result. Two decedents in their 30s and 80s could not be assigned an age group. Likelihood might have had more significant influence than prior probability. Bayesian approach and new scoring system of thyroid cartilage ossification might be useful as an age estimation method. Although the low posterior probability in decedents the age ≧70 remains a problem, the advantage of Bayesian estimation that it can sequentially update the age estimation table by factoring in exceptional data can solve this problem. In this study, accuracy of age estimation did not dramatically increase, however, Bayesian statistics might become a useful technique for examining any tissue samples subject to age-related calcification.

The Laryngohyoid Complex in Medicolegal Death Investigations

The laryngohyoid complex, composed of the hyoid bone and laryngeal cartilages, can be of interest in the autopsy setting, particularly when injuries are observed. Analysis of trauma to this structure can assist in establishing cause and manner of death. In many situations, the forensic anthropologist, with their expertise in analyzing bone and cartilage trauma, can assist in analyzing trauma to this complex. Although researchers have tried to study the relationships between causes of trauma to the osseocartilaginous structure and the observed injury pattern, they have not been successful in identifying unique signatures associated with different causes of trauma. This is because different causes can result in the same or similar injury patterns. In addition, variation due to growth and development or due to remote injury may change the structure's biomechanical response. The goal of this paper is to address issues that a forensic pathologist may encounter when assessing potential trauma to the osseocartilaginous structures of the laryngohyoid complex; in particular, it focuses on anatomical variants and trauma resulting from various causes.

Micro computed tomography features of laryngeal fractures in a case of fatal manual strangulation

Cases of subtle fatal neck compression are often complicated by the lack of specificity of the post-mortem signs of asphyxia and by the lack of clear signs of neck compression. Herein we present a forensic case of a 45-year-old schizophrenic patient found on the floor of the bedroom of a psychiatric ward in cardiopulmonary arrest and who died after two days in a vegetative state. The deposition of the roommate of the deceased, who claimed responsibility for the killing of the victim by neck compression, was considered unreliable by the prosecutor. Autopsy, toxicological analyses, and multi-slice computed tomography (MSCT), micro computed tomography (micro-CT) and histology of the larynx complex were performed. Particularly, micro-CT analysis of the thyroid cartilage revealed the bilateral presence of ossified triticeous cartilages and the complete fragmentation of the right superior horn of the thyroid, but it additionally demonstrated a fracture on the contralateral superior horns, which was not clearly diagnosable at MSCT. On the basis of the evidence of intracartilaginous laryngeal hemorrhages and bilateral microfracture at the base of the superior horns of the larynx, the death was classified as a case of asphyxia due to manual strangulation. Micro-CT was confirmed as a useful tool in cases of subtle fatal neck compression, for the detection of minute laryngeal cartilage fractures, especially in complex cases with equivocal findings on MSCT.

The use of computed tomography in determining development, anomalies, and trauma of the hyoid bone

PURPOSE

Recognition of injury to the hyoid bone is intrinsic to post-mortem examination. Given its superficial location in the neck hyoid fractures are generally associated with some form of compressive neck force although they are well recognized in the peri-mortem period, in the context of manual handling and resuscitation. Hyoid fractures are variably reported to occur in manual strangulation and during hanging.

METHODS

In this study Computer Tomography (CT) scans of the head and neck of 431 deceased persons (235 males and 196 females) between the ages of 1 day and 100 years of age (mean age 35.93 ± 24.15) and including 25 victims of hangings were examined to reveal the pattern of age-related change and the types of injury that occurred. Hyoid variants were also documented.

RESULTS

The synchondroses between greater cornua and body were found to progressively fuse with age although in the current sample 20% non-fusion was observed beyond 65 years of age. Sex differences were evident in adult hyoid bones and discriminant function analysis correctly confirmed sex in 74.7% of cases.

CONCLUSIONS

The greatest age-related changes occurred from puberty to post-adolescence and a linear regression equation successfully assessed age into three general categories in 87.7% of cases. Hyoid fractures were documented in 24% of victims of hangings and while previous reports indicate these are more likely in older age, when synchondroses are fused, in this study the average age of victims with fracture was 27 ± 10 years. In the majority of cases the site of ligature was below the hyoid bone and in only one on the hyoid body.

Agenesis of the superior cornua of the thyroid cartilage: a rare variant of medicolegal importance

It is important that forensic pathologists are familiar with variations in the size and shape of the laryngohyoid complex when interpreting injuries and pathology of the head and neck region. Accurate postmortem examination of the laryngohyoid structures may be difficult if anatomical variation in these structures is present. Agenesis of the upper horns of the thyroid cartilage has medicolegal significance because it may be mistaken for a fracture or other trauma-related conditions. We present 3 cases with different forms of agenesis of the superior cornu of the thyroid cartilage, namely, right unilateral, left unilateral, and bilateral agenesis.