Atypical wound trajectory after a tangential pistol shot

Three intermediate-range shots from a Browning, model 1955, 7.65 mm caliber, pistol were fired from the driver's seat of a car at a woman in the passenger seat. She sustained three wounds: An, ultimately fatal, penetrating head wound, a graze wound across her forehead, and a tangential, perforating, wound, with bullet entry over the medial sternum and exit through the right flank. Neither postmortem CT nor forensic autopsy discovered bony thoracic injuries or perforations of the thoracoabdominal cavities. There was pulmonary contusion in the medial lobe of the right lung and hemorrhage in the adipose tissue around the right kidney. The tangential bullet had left an almost 40-cm-long wound channel through a pronounced layer of subcutaneous fat. Based on 3D reconstructed CT-data determinations, a straight bullet trajectory between entry and exit wounds would have traversed the abdominothoracic cavities, right lung, and liver. The actual trajectory, however, described a prominent curve, without signs of deflection by bone. Postulated explanations for this unusual bullet track are that the woman was twisting her body in a dynamic scene when the bullet struck; further, due to its shallow angle of incidence on the skin, the bullet was deflected to an intracutaneous path. Additionally, soft tissue resistance may have caused the bullet to yaw. Caution should, thus, be exercised when reconstructing bullet trajectories solely from entry and exist wounds, also for bullet wounds through basically homogenous soft tissues.

The death of King Charles XII of Sweden revisited

The death of King Charles XII of Sweden has remained as a mystery for more than three centuries. Was he assassinated by his own men or killed by the enemy fire? Charles was killed by a projectile perforating his skull from left to right. In this study, we utilized a Synbone ballistic skull phantom and modern radiological imaging to clarify the factors behind the observed head injuries. We examined whether a musket ball fired from the enemy lines would be the most potential projectile. Our experiments with a leaden 19.5 mm musket ball demonstrated that at velocities of 200 to 250 m/s, it could cause similar type of injuries as observed in the remains of Charles . The radiological imaging supported the theory that the projectile was not a leaden but of some harder metal, as we could detect remnants of lead inside the wound channel unlike in Charles' case. In addition, our experiments showed that a 19.5mm musket ball  produces max. 17mm hole into a felt material  . The main evidence supporting 19.5 mm projectile size has been a 19-19.5mm bullet hole in a hat that Charles was wearing during his death. Additional experiments with a 25.4 mm steel ball produced approximately 20 mm hole in the felt. As our musket ball experiments also resulted in considerably smaller cranial injuries than those in Charles' case, we can conclude that the deadly projectile wasn't leaden and was more than 19.5 mm in diameter, potentially an iron cartouche ball that was shot from the enemy lines.

CT of Penetrating Abdominopelvic Trauma

Penetrating abdominopelvic trauma usually results from abdominal cavity violation from a firearm injury or a stab wound and is a leading cause of morbidity and mortality from traumatic injuries. Penetrating trauma can have subtle or complex imaging findings, posing a diagnostic challenge for radiologists. Contrast-enhanced CT is the modality of choice for evaluating penetrating injuries, with good sensitivity and specificity for solid-organ and hollow viscus injuries. Familiarity with the projectile kinetics of penetrating injuries is an important skill set for radiologists and aids in the diagnosis of both overt and subtle injuries. CT trajectography is a useful tool in CT interpretation that allows the identification of subtle injuries from the transfer of kinetic injury from the projectile to surrounding tissue. In CT trajectography, after the entry and exit wounds are delineated, the two points can be connected by placing cross-cursors and swiveling the cut planes obliquely in orthogonal planes to obtain a double-oblique orientation to visualize the wound track in profile. The path of the projectile and its ensuing damage is not always straight, and the imaging characteristics of free fluid of different attenuation in the abdomen (including hemoperitoneum) can support the diagnosis of visceral and vascular injuries. In addition, CT is increasingly used for evaluation of patients after damage control surgery and helps guide the management of injuries that were overlooked at surgery. An invited commentary by Paes and Munera is available online. Online supplemental material is available for this article. ©RSNA, 2021.

Imaging Ballistic Injuries

Here in Canada, we often think of gun violence as confined to conflict zones, terrorism, and more of a problem for our southern neighbor. However, in recent years, it has also become a Canadian problem with increased gun violence related to criminal activity presenting in daily practice. Radiologists play a critical role in the evaluation of ballistic trauma and must therefore be familiar with both the common and uncommon patterns of ballistic injury. In this article, we review the mechanisms of ballistic trauma as well as their resultant injury patterns in order to guide image interpretation.

Synergistic Role of Newer Techniques for Forensic and Postmortem CT Examinations

OBJECTIVE

The aim of this article is to provide an overview of newer techniques and postprocessing tools that improve the potential impact of CT in forensic situations.

CONCLUSION

CT has become a standard tool in medicolegal practice. Postmortem CT is an essential aid to the pathologist during autopsies. Advances in technology and software are constantly leading to advances in its performance.

Combat radiology: Challenges and opportunities

Radiology services in a combat situation are essentially centred on assisting the battle field physicians/surgeons to save/salvage life and limb. Timely and accurate detection of type and mapping of extent of injury can aid in making imaging based triage which can be of immense help to the treating physicians/trauma surgeons. With the availability of rapid assessment (clinical as well as imaging based) and quick transport facility, the focus has gradually been shifting from merely limb-saving to life-saving strategies. Providing the right imaging modality at the right time for the right patient at the right place is the need of the hour and will dictate the success of combat casualty care. Although there are limitations in terms of terrain and hostility in a combat scenario, newer developments in the field of Radiodiagnosis and imaging can be optimally utilized for better casualty care services. Point of care Digital/Computed Radiography and basic Ultrasonography for trauma complemented by usage of multidetector computed tomography will go a long way in helping timely and accurate management of victims of blast and ballistic injury in a combat scenario. Following a rigid, easy to understand yet comprehensive protocol and radiology reporting system will be invaluable in the combat scenario despite various limitations.

Multidetector CT for Penetrating Torso Trauma: State of the Art

The use of computed tomography (CT) for hemodynamically stable victims of penetrating torso trauma continues to increase but remains less singular to the work-up than in blunt trauma. Research in this area has focused on the incremental benefits of CT within the context of evolving diagnostic algorithms and in conjunction with techniques such as laparoscopy, endoscopy, and angiographic intervention. This review centers on the current state of multidetector CT as a triage tool for penetrating torso trauma and the primacy of trajectory evaluation in diagnosis, while emphasizing diagnostic challenges that have lingered despite tremendous technological advances since CT was first used in this setting 3 decades ago. As treatment strategies have also changed considerably over the years in parallel with advances in CT, current management implications of organ-specific injuries depicted at multidetector CT are also discussed.

Firearms, bullets, and wound ballistics: an imaging primer

Based on its intrinsic mass and velocity, a bullet has an upper limit of wounding potential. Actual wound severity is a function of the bullet construction and trajectory, as well as the properties of the tissues traversed. Interpreting physicians must evaluate the bullet trajectory and describe patterns of injury resulting from the effect of energy transfer from the projectile into living tissue. A basic understanding of firearms, projectiles, and wound ballistics can help the interpreting physicians in conceptualizing these injuries and interpreting these cases.

Penetrating wounds to the torso: evaluation with triple-contrast multidetector CT

Penetrating injuries account for a large percentage of visits to emergency departments and trauma centers worldwide. Emergency laparotomy is the accepted standard of care in patients with a penetrating torso injury who are not hemodynamically stable and have a clinical indication for exploratory laparotomy, such as evisceration or gastrointestinal bleeding. Continuous advances in technology have made computed tomography (CT) an indispensable tool in the evaluation of many patients who are hemodynamically stable, have no clinical indication for exploratory laparotomy, and are candidates for conservative treatment. Multidetector CT may depict the trajectory of a penetrating injury and help determine what type of intervention is necessary on the basis of findings such as active arterial extravasation and major vascular, hollow viscus, or diaphragmatic injuries. Because multidetector CT plays an increasing role in the evaluation of patients with penetrating wounds to the torso, the radiologists who interpret these studies should be familiar with the CT findings that mandate intervention.

Semi-automated trajectory analysis of deep ballistic penetrating brain injury

BACKGROUND

Penetrating head injuries (PHIs) are common in combat operations and most have visible wound paths on computed tomography (CT).

OBJECTIVE

We assess agreement between an automated trajectory analysis-based assessment of brain injury and manual tracings of encephalomalacia on CT.

METHODS

We analyzed 80 head CTs with ballistic PHI from the Institutional Review Board approved Vietnam head injury registry. Anatomic reports were generated from spatial coordinates of projectile entrance and terminal fragment location. These were compared to manual tracings of the regions of encephalomalacia. Dice's similarity coefficients, kappa, sensitivities, and specificities were calculated to assess agreement. Times required for case analysis were also compared.

RESULTS

Results show high specificity of anatomic regions identified on CT with semiautomated anatomical estimates and manual tracings of tissue damage. Radiologist's and medical students' anatomic region reports were similar (Kappa 0.8, t-test p < 0.001). Region of probable injury modeling of involved brain structures was sensitive (0.7) and specific (0.9) compared with manually traced structures. Semiautomated analysis was 9-fold faster than manual tracings.

CONCLUSION

Our region of probable injury spatial model approximates anatomical regions of encephalomalacia from ballistic PHI with time-saving over manual methods. Results show potential for automated anatomical reporting as an adjunct to current practice of radiologist/neurosurgical review of brain injury by penetrating projectiles.

Penetrating diaphragmatic injury: accuracy of 64-section multidetector CT with trajectography

PURPOSE

To (a) determine the diagnostic performance of 64-section multidetector computed tomography (CT) trajectography for penetrating diaphragmatic injury (PDI), (b) determine the diagnostic performance of classic signs of diaphragmatic injury at 64-section multidetector CT, and (c) compare the performance of these signs with that of trajectography.

MATERIALS AND METHODS

This HIPAA-compliant retrospective study had institutional review board approval, with a waiver of the informed consent requirement. All patients who had experienced penetrating thoracoabdominal trauma, who had undergone preoperative 64-section multidetector CT of the chest and abdomen, and who had surgical confirmation of findings during a 2.5-year period were included in this study (25 male patients, two female patients; mean age, 32.6 years). After a training session, four trauma radiologists unaware of the surgical outcome independently reviewed all CT studies and scored the probability of PDI on a six-point scale. Collar sign, dependent viscera sign, herniation, contiguous injury on both sides of the diaphragm, discontinuous diaphragm sign, and transdiaphragmatic trajectory were evaluated for sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV). Accuracies were determined and receiver operating characteristic curves were analyzed.

RESULTS

Sensitivities for detection of PDI by using 64-section multidetector CT with postprocessing software ranged from 73% to 100%, specificities ranged from 50% to 92%, NPVs ranged from 71% to 100%, PPVs ranged from 68% to 92%, and accuracies ranged from 70% to 89%. Discontinuous diaphragm, herniation, collar, and dependent viscera signs were highly specific (92%-100%) but nonsensitive (0%-60%). Contiguous injury was generally more sensitive (80%-93% vs 73%-100%) but less specific (50%-67% vs 83%-92%) than transdiaphragmatic trajectory when patients with multiple entry wounds were included in the analysis. Transdiaphragmatic trajectory was a much more sensitive sign of PDI than previously reported (73%-100% vs 36%), with NPVs ranging from 71% to 100% and PPVs ranging from 85% to 92%.

CONCLUSION

Sixty-four-section multidetector CT trajectography facilitates the identification of transdiaphragmatic trajectory, which accurately rules in PDI when identified. Contiguous injury remains a highly sensitive sign, even when patients with multiple injuries are considered, and is useful for excluding PDI.