Neck-MRI experience for investigation of survived strangulation victims

Did George Floyd Die of Cardioinhibition From Pressure on His Neck?

Introduction: Did George Floyd die from Officer Chauvin's knee triggering reflex cardioinhibition an instantaneous neurogenic cardiac arrest (INCA)? Objectives: This study was conducted to assess the findings necessary to conclude what constitutes an INCA death and apply them to the George Floyd case. Methods: We performed an intensive iterative search of the literature for such deaths. Results: The carotid sinus responds to neck pressure causing a neurogenic reflex mediated through the vagal nerve that causes cardioinhibition. This reflex may result in syncope, which occurs predominantly in young females and older males. Seven deaths occurred from carotid sinus massage, causing ventricular fibrillation. Twenty-seven purported INCA deaths were reported based on a history of near-instantaneous collapse, absence of evidence of vital reaction at death, or hemorrhage in "reflex zones." INCA deaths must be distinguished from those from emotional stress resulting in sympathetic action, rather than parasympathetic action. We found that the reported INCA deaths occur in young and old adults with and without underlying cardiac pathology. Conclusion: The death of George Floyd is unlikely to have been from a rare lethal neck reflex mechanism; other causes and mechanisms of death can explain his death. He did not die instantaneously of neck pressure but prolonged neck pressure. The initial cardiac rhythm was pulseless electrical rhythm, not a ventricular arrhythmia. Neither absence of vital reaction nor hemorrhage in a reflex zone was found at autopsy. We conclude that George Floyd did not die of INCA from pressure on his neck.

The current state of forensic imaging- clinical forensic imaging

Clinical forensic imaging could be defined as the use of imaging first realised for medical care as evidence for a judicial purpose. It requires both forensic experts and clinical radiologists to have a good understanding of imaging modalities and indications and a solid knowledge of the correct terminology. This second part of the review describes the main situations in which imaging may be used for forensic purposes, i.e. blunt trauma, penetrating injuries, asphyxia, physical abuse and neglect.

[Strangulation]

CLINICAL PROBLEM

Detection of manual strangulation, choking and hanging, as well as the intensity of these actions, helps to clarify the course of events, to enforce the state's right to prosecute and ultimately to protect against further attacks. However, this is complicated by the scarcity of externally visible findings.

STANDARD PROCEDURE TO DATE

The forensic examination of the head and neck after strangulation is carried out by means of external inspection to detect injuries and congestion above the strangulation level. Lesions below the surface of the skin, in particular of the subcutaneous fat tissue, the muscles or the laryngeal structures, usually escape the external inspection.

FORENSIC RADIOLOGY AS AN IMPORTANT COMPONENT

Imaging techniques allow internal injuries to be recorded and objectified, which can be of considerable added value in the collection of evidence. Since criminal proceedings must meet the highest standards of security, high demands are placed on imaging and diagnosis.

ASSESSMENT

Imaging techniques are suitable for detecting and objectifying internal injuries after a person has survived strangulation. However, their excellent reconstruction and visualization capabilities also make them a valuable addition to postmortem examinations.

RECOMMENDATIONS FOR PRACTICE

After reported and survived strangulation, choking or hanging, magnetic resonance imaging (MRI) of the soft tissues of the neck should be performed as soon as possible, and if cerebral damage is suspected, the skull should also be examined. If the event was not survived, whole-body computed tomography (CT) is now standard practice at many forensic medicine institutes.

Longitudinal visibility of MRI findings in living victims of strangulation

Initial experiences with magnetic resonance imaging (MRI) of living strangulation victims demonstrated additional findings of internal injuries compared to the standard clinical forensic examination. However, existing studies on the use of MRI for this purpose mostly focused on the first 48 h after the incident. The aims of this study were (a) to evaluate the longitudinal visibility of MRI findings after violence against the neck by performing two MRI examinations within 12 days and a minimum of four days between both MRI scans and (b) to assess which MRI sequences were most helpful for the detection of injuries. Twenty strangulation victims participated in this study and underwent one (n = 8) or two (n = 12) MRI scans. The first MRI examination was conducted during the first five days, the second five to 12 days after the incident. Two blinded radiologists assessed the MRI data and looked for lesions in the structures of the neck. In total, 140 findings were reported in the 32 MRI examinations. Most of the findings were detected in the thyroid and the muscles of the neck. T2-weighted SPACE with fat suppression, T1-weighted TSE and T1-weighted MPRAGE were rated as the most helpful MRI sequences. Subjects who showed findings in the initial scan also demonstrated comparable results in the second scan, which was performed on average 8.4 days after the incident. Our results show that even up to 12 days after the incident, the criminal proceeding of strangulation cases may greatly profit from the information provided by an MRI examination of the neck in addition to the standard clinical forensic examination.

Under-reporting of forensic findings: craniocervical emergency imaging in cases of survived hanging

To determine the diagnostic bias between clinical and forensic radiology in cases of nonfatal hanging and determine and describe typical underreported imaging findings. In a retrospective, single-center study, all patients admitted for attempted suicide with near-hanging or fatal hanging between January 2008 and December 2020 who received CT or MRI of head and neck were reviewed and missed findings in the original report were documented. A binary regression with disagreement as dependent variable was fitted for the imaging modality, fatality, age, and sex. A total of 123 hanging incidents were retrospectively analyzed. The vast majority (n = 108; 87.8%) had attempted suicide with a nonfatal outcome. Fatal outcome occurred in 15 (12.0%). The extra- and intracranial injuries documented on CT and MRI scans were laryngeal (n = 8; 6.5%), soft tissue (n = 42; 34.1%), and vascular injuries (n = 1; 0.8%). Intracranial pathology was evident on 18 (14.6%) scans. Disagreement occurred in 36 (29.3%) cases and represented 52 (69.2%) of all cases with a radiological finding. Disagreement was strongly associated with fatality (OR: 2.7-44.9.4, p = 0.0012). In most cases, nonfatal hangings cause no or only minor injuries. Fatal cases are associated with a greater probability of missed minor imaging findings. This suggests that findings deemed clinically irrelevant are probably not reported in such severe emergency cases. This association indicates that minor abnormalities are underreported when major pathologies are evident on imaging in victims of strangulation.

Medical evidence assisting non-fatal strangulation prosecution: a scoping review

OBJECTIVES

Non-fatal strangulation (NFS) is a serious form of gendered violence that is fast becoming an offence in many jurisdictions worldwide. However, it often leaves little or no externally visible injuries making prosecution challenging. This review aimed to provide an overview of how health professionals can support the prosecution of criminal charges of NFS as part of regular practice, particularly when externally visible injuries are absent.

METHOD

Eleven databases were searched with terms related to NFS and medical evidence in health sciences and legal databases. Eligible articles were English language and peer reviewed, published before 30 June 2021; sample over 18 years that had primarily survived a strangulation attempt and included medical investigations of NFS injuries, clinical documentation of NFS or medical evidence related to NFS prosecution.

RESULTS

Searches found 25 articles that were included for review. Alternate light sources appeared to be the most effective tool for finding evidence of intradermal injury among NFS survivors that were not otherwise visible. However, there was only one article that examined the utility of this tool. Other common diagnostic imaging was less effective at detection, but were sought after by prosecutors, particularly MRIs of the head and neck. Recording injuries and other aspects of the assault using standardised tools specific for NFS were suggested for documenting evidence. Other documentation included writing verbatim quotes of the experience of the assault and taking good quality photographs that could assist with corroborating a survivor's story and proving intent, if relevant for the jurisdiction.

CONCLUSION

Clinical responses to NFS should include investigation and standardised documentation of internal and external injuries, subjective complaints and the experience of the assault. These records can assist in providing corroborating evidence of the assault, reducing the need for survivor testimony in court proceedings and increasing the likelihood of a guilty plea.

MRI Segmentation of Cervical Muscle Volumes in Survived Strangulation: Is There an Association between Side Differences in Muscle Volume and the Handedness of the Perpetrator? A Retrospective Study

We evaluate the potential value of magnetic resonance imaging (MRI) in the examination of survivors of manual strangulation. Our hypothesis was that trauma-induced edema of the cervical muscles might lead to a side difference in the muscle volumes, associated with the handedness of the perpetrator. In 50 individuals who survived strangulation, we performed MRI-based segmentation of the cervical muscle volumes. As a control group, the neck MRIs of 10 clinical patients without prior trauma were used. The ratio of the right to left muscle volume was calculated for each muscle group of the control and strangulation groups. Cutoff values for the assumed physiological muscle volume ratios between the right and left sides were identified from our control group. There was no significant difference among the individuals in the pathological muscle volume ratio between right-handed versus both-handed strangulation for the sternocleidomastoid, pretracheal, anterior deep, or trapezoid muscle groups. Only the posterior deep muscle group showed a statistically significant difference in the pathological muscle volume ratio for both-handed strangulations (p = 0.011). Measurement of side differences in cervical muscle volume does not allow for a conclusion concerning the probable handedness of the perpetrator.