Identification of gunshot entry wounds using hyperdense rim sign on post-mortem computed tomography

Abstract

Post-mortem computed tomography (PMCT) is an increasingly utilized tool in forensic medicine for evaluating head gunshot injuries. Vault bevelling sign, when present, provides information regarding entry and exit wounds; when absent, identifying wound type on PMCT remains challenging. A cutaneous hyperdense ring, described in an animal study by Junno et al. (2022), may be indicative of contact shots. We hypothesized that it could also be observed in human gunshot injuries. Our study evaluates the reliability of the cutaneous hyperdense rim sign for identifying entry gunshot wounds in PMCT. After excluding complex and mucosal wounds, two operators retrospectively evaluated 64 gunshot wounds (30 entry and 34 exit wounds) in 34 head PMCT cases (2018–2022). Gold standard for wound type determination was the autopsy report. The hyperdense rim sign was defined as at least two-thirds of a continuous cutaneous hyperdense circle on a multiplanar reconstruction of cutaneous tissue tangent to the wound. The hyperdense rim sign demonstrated a specificity of 97% (95% CI: 85–100%) and a sensitivity of 63% (95% CI: 44–80%) for identifying entry wounds. Moreover, in 16 external examination reports where the presence of powder residues or bullet wipe at entry wound was explicitly mentioned, a positive association was observed between hyperdense rim sign and the presence of these elements (p = 0.018). These findings suggest that the hyperdense rim sign, when present, may be a valuable tool for entry wound determination in gunshot injuries, interpreted in conjunction with other CT and autopsy features.

Full text

Vol.:(0123456789)
International Journal of Legal Medicine (2025) 139:619–626
https://doi.org/10.1007/s00414-024-03362-5
ORIGINAL ARTICLE
Identification ofgunshot entry wounds using hyperdense rim sign
onpost-mortem computed tomography
EmilienJupin‑Delevaux1· CorentinProvost1,2· GhaziHmeydia1,2· Marie‑EdithRichard1,2· LiliaHamza3,4·
TaniaDelabarde3,4· MarieCrahès3· ValidirePierre3,5· BertrandLudes3,4· CatherineOppenheim1,2·
JosephBenzakoun1,2
Received: 26 December 2023 / Accepted: 25 October 2024 / Published online: 31 October 2024
© The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2024
Abstract
Post-mortem computed tomography (PMCT) is an increasingly utilized tool in forensic medicine for evaluating head gunshot
injuries. Vault bevelling sign, when present, provides information regarding entry and exit wounds; when absent, identify-
ing wound type on PMCT remains challenging. A cutaneous hyperdense ring, described in an animal study by Junno etal.
(2022), may be indicative of contact shots. We hypothesized that it could also be observed in human gunshot injuries. Our
study evaluates the reliability of the cutaneous hyperdense rim sign for identifying entry gunshot wounds in PMCT. After
excluding complex and mucosal wounds, two operators retrospectively evaluated 64 gunshot wounds (30 entry and 34 exit
wounds) in 34 head PMCT cases (2018–2022). Gold standard for wound type determination was the autopsy report. The
hyperdense rim sign was defined as at least two-thirds of a continuous cutaneous hyperdense circle on a multiplanar recon-
struction of cutaneous tissue tangent to the wound. The hyperdense rim sign demonstrated a specificity of 97% (95% CI:
85–100%) and a sensitivity of 63% (95% CI: 44–80%) for identifying entry wounds. Moreover, in 16 external examination
reports where the presence of powder residues or bullet wipe at entry wound was explicitly mentioned, a positive association
was observed between hyperdense rim sign and the presence of these elements (p = 0.018). These findings suggest that the
hyperdense rim sign, when present, may be a valuable tool for entry wound determination in gunshot injuries, interpreted
in conjunction with other CT and autopsy features.
Keywords Postmortem computed tomography· Gunshot wounds· Forensic imaging· Forensic ballistics· Gunshot entry
wound identification
Introduction
Gunshot wounds are a major cause of violent deaths world-
wide, with hundreds of thousands of individuals killed or
injured by firearms each year [1]. Accurate identification of
entry wounds is crucial for understanding the circumstances
surrounding these deaths, as it can provide important infor-
mation about the trajectory of the projectile, the position of
the shooter and victim at the time of firing, and possibly the
distance from which the shot was fired. However, the iden-
tification of entry wounds can be challenging, particularly
when entry and exit wounds display similar features or when
bone deformations and projectile fragments complicate the
interpretation of injuries [2].
Traditionally, autopsy has been the gold standard method
for examining gunshot wounds and determining the circum-
stances surrounding death. However, autopsy is invasive,
* Joseph Benzakoun
j.benzakoun@ghu-paris.fr
1 Service de Radiologie, GHU Paris Psychiatrie Et
Neurosciences, Site Sainte-Anne, 1, Rue Cabanis,
75014Paris, France
2 Institute ofPsychiatry andNeuroscience ofParis (IPNP),
Université Paris Cité, INSERM U1266, 75014Paris, France
3 Institut Medico-Légal de Paris, Paris, France
4 Pôle Universitaire d’imagerie Post-Mortem, Université de
Paris, Paris, France
5 Département d’Anatomie Pathologique, Institut Mutualiste
Montsouris, Paris, France
Content courtesy of Springer Nature, terms of use apply. Rights reserved.