|Year : 2021 | Volume
| Issue : 1 | Page : 33-35
Comparison of computed tomography imaging with traditional autopsy results
Yang Li1, Yang Li2, Bin Wu2, Bin Wu1, Yongbo Wu2, Hongliang Zhu3, Jian Wang1, Jianjun Li2, Guanglong He1
1 Department of Forensic Pathology and Traumatology, the Institute of Forensic Sciences, Ministry of Public Security, Beijing, China
2 Public Security Bureau of Shijiazhuang City; Criminal Police Detachment, Shijiazhuang, Hebei Province, China
3 Department of Forensic Pathology and Traumatology, the Institute of Forensic Sciences, Ministry of Public Security, Beijing; Department of Forensic Medicine, Zunyi Medical College, Zunyi, Guizhou, China
|Date of Submission||09-Dec-2020|
|Date of Acceptance||28-Dec-2020|
|Date of Web Publication||24-Mar-2021|
Department of Pathological Injury Technology, Center of Evidence Identification, Ministry of Public Security, Beijing 100038
Source of Support: None, Conflict of Interest: None
The role of computed tomography (CT) images in forensic identification has been widely recognized. Such images can provide an important basis for identification of the cause of death in complicated and difficult cases, including falls from a height, drowning, explosion and gunshot cases, traffic accidents, and sudden death. However, few reports have focused on the application of CT images in cases of death caused by sharp object injuries. Therefore, the CT images and autopsy findings were compared in a case of death caused by sharp object injuries to the chest and abdomen, and the importance of CT images in cases of death from common sharp object injuries is herein discussed.
Keywords: Autopsy, morphological comparison, postmortem computed tomography image, sharp object injury
|How to cite this article:|
Li Y, Li Y, Wu B, Wu B, Wu Y, Zhu H, Wang J, Li J, He G. Comparison of computed tomography imaging with traditional autopsy results. J Forensic Sci Med 2021;7:33-5
|How to cite this URL:|
Li Y, Li Y, Wu B, Wu B, Wu Y, Zhu H, Wang J, Li J, He G. Comparison of computed tomography imaging with traditional autopsy results. J Forensic Sci Med [serial online] 2021 [cited 2021 Jun 14];7:33-5. Available from: https://www.jfsmonline.com/text.asp?2021/7/1/33/311864
| Brief Case Description|| |
In October 2019 in a city in Hebei Province, a woman had a dispute with a male suspect in a room, and the suspect left. When the woman's relatives entered the room, they saw her lying on her back with a small amount of blood on the ground, and they called the police and emergency services. After the emergency personnel arrived at the scene, they confirmed that the woman had no vital signs and that her spleen was exposed. They placed the exposed spleen back into the abdominal cavity and sutured the wound.
| Computed Tomography Scanning Parameters|| |
A computed tomography (CT) examination was performed using a 16-slice helical CT scanner (ANATOM 16; Shenzhen Anke High-tech Co., Ltd., Shenzhen, China). The scanning tube voltage was 140 kV, the collimation was 64 mm × 0.6 mm, and the slice thickness was 10 mm. The soft-tissue window and bone window were used, and the visual field automatically adapted to the object. Images were adjusted, and Hounsfield unit (HU) values were measured using a digital radiographic management system (NFviwer; Nanfang DICOM image browser software).
The CT values of tissues were measured at 10 independent points of interest in the CT images of the corresponding tissues at the horizontal position, and the mean HU values were taken as the CT values of the tissues.
| Comparison of Autopsy Findings and Computed Tomography Images|| |
Skin wounds and organ injuries
A 7.5-cm sutured wound was present from the seventh to ninth ribs along the left posterior axillary line. The suture was removed, and examination revealed that one of the wound angles was blunt and the other was sharp, the wound edge was flat, and no intertissue bridge was present. The seventh rib on the posterior side of the interior wall of the left thoracic cavity was fractured with flat broken ends, and the upper pole of the spleen was detached. The right thoracic cavity contained 400 mL of hemorrhage and 140 g of clotted blood, and the left thoracic cavity contained 500 mL of hemorrhage and 480 g of clotted blood. The left lung was collapsed. A 4.0-cm wound was visible on the anterior side of the T5 vertebra in the left thoracic cavity and extended to the right thoracic cavity. A 0.5-cm wound was visible at the right pulmonary hilum. A 10.0-cm × 5.0-cm hematoma was present in the surrounding soft tissues. A major portion of the thoracic aorta was transected when the hematoma was separated, and the broken ends were flat [Figure 1]e.
|Figure 1: Computed tomography images of coagulated blood in the skin wounds and organ injuries. (a) Dotted arrow: Skin wound; black arrow: Spleen rupture; triangles: Subcutaneous pneumatosis. (b) Thoracic organs. #hemorrhage, *clots. (c) High-density shadow around the artery. (d) The artery wall was discontinuous (arrow). (e) Gross observation of thoracic artery rupture|
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Computed tomography images
The posterior one-third of the seventh rib showed an extroverted fracture with sharp broken ends. The continuity of skin on the left waist and back was interrupted, a gas shadow was present in the muscle space, and one pole of the spleen was broken [Figure 1]a. A small piece of free spleen tissue was present on the ventral side without a significant liquid shadow surrounding it. The left and right lung shadows were close to the anterior wall of the thoracic cavity, and their average CT value was 20 HU. Blood had accumulated in the middle thoracic cavity, and its average CT value was 70 HU. A crescent-shaped high-density shadow was located close to the posterior thoracic wall, and its average CT value was 110 HU [Figure 1]b. Anterior to the T5 vertebra, the continuity of the contour of the thoracic aorta was interrupted [Figure 1]c, an approximately 5-mm-long oblique rupture was present, and a dense shadow with an average CT value of 70 HU could be seen around it [Figure 1]d.
Measurement of wound length
The wound was exposed. The wound cavity extended diagonally from the bottom left to the top, and the damaged organs identified from exterior to interior were the spleen, diaphragm, thoracic aorta, and right hilum.
Computed tomography images
The continuity of the skin on the seventh rib along the left posterior axillary line was interrupted for a length of about 80 mm, affecting eight CT slices. The penetrating wound passed through the thoracic aorta anterior to the T5 vertebra from the left back, the central hole of the diaphragm, and then the right hilum, spanning 10 CT slices [Figure 2]a. The length of the affected organs was about 176 mm [Figure 2]b. According to the CT image, the wound cavity length was about 21 cm. The sharp object that had caused the injuries was identified as a handheld knife with a single-edged blade length of 15 cm [Figure 2]c.
|Figure 2: Computed tomography images of wounds and the wound channels of the sharp object injury in the waist and abdomen. (a) Measurement of wound channel depth: number of computed tomography slices affected by injuries. Discontinuity of the skin. (b) Wound channel length. The double arrows show the length between the skin and aortic rupture. (c) Sharp object used to cause the fatal injuries|
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| Discussion|| |
Comparison of the CT images with the autopsy findings in this case showed that the CT images could more effectively display the soft tissue and organ injuries of the deceased, including sharp object skin injuries, rib fractures, spleen fractures, arterial rupture, chest hemorrhage, and blood coagulation. Moreover, the CT images effectively facilitated the localization of injuries that were difficult to examine during autopsy, such as subcutaneous pneumatosis.
Virtual autopsy has many advantages over traditional autopsy methods. Virtual autopsy can provide a beneficial supplement to traditional autopsy methods;, for example, CT can more effectively display certain pathological changes (e.g., gas embolism) and display more detailed morphological features (e.g., in comminuted skull fractures) than a traditional camera. Forensic experts in China have begun to explore the application of CT in cases involving various causes of death, such as traffic accident, sudden death, and drowning. However, few reports have focused on the practical application of CT scanning in cases of mechanical injuries, especially sharp object injuries.
The volume of blood in the body cavities of the corpse, the nature of blood clots, and the state of hematomas are important for forensic experts to judge the amount of bleeding, the time of bleeding, and the antemortem versus postmortem nature of the injuries. Blood has a higher density than other body fluids, and the density can change according to the duration, degree, and location of hematomas; therefore, the CT value can be used to identify the state of blood in the body (e.g., hemorrhage, coagulation, hematoma, or thrombi). The CT value of flowing blood usually ranges from 35 to 45 HU, whereas the CT value of coagulated blood is slightly higher at 45–70 HU. On CT images, hematomas present as high-density shadows, which are used by clinicians to identify the most serious point of abdominal hemorrhage after trauma. In the present case, a CT scan was performed before dissection and revealed both large clots and unclotted blood in the bilateral thoracic cavity of the deceased, indicating with fairly good certainty the most serious point of abdominal hemorrhage. During the thoracotomy, blood was prevented from flowing and the accumulated blood was smoothly removed to further accurately calculate the amount of bleeding and provide a basis for the mechanism of death induced by hemorrhagic shock. However, few studies have focused on how the “chicken fat-like” blood coagulation commonly found in forensic cases differs from antemortem blood coagulation and thrombosis. Therefore, further studies are needed to clarify the principles underlying the changes in the CT values of postmortem blood.
The wound cavity depth is an important guiding value for assessing the tools used to induce injuries, especially for judging the blade length of sharp objects such as daggers. In forensic clinical identification, B-ultrasonography is often used to measure the length of the healed wound cavity, thus identifying the injury. Measuring the depth of the wound cavity using CT images before autopsy is a new technique in forensic practice. Inferring the blade length of a sharp object in CT images before dissection can avoid errors due to deformation of the wound channel caused by the autopsy procedure; it can also provide assistance during the classical method of probing the wound channel. In the present case, the blade length measured in CT images was longer than the actual blade. This might have been due to the influence of factors such as the high penetration force of the criminal and the skin elasticity of the deceased, causing the wound to be longer than the blade. Therefore, although CT scanning is an auxiliary technology that can provide important information for forensic experts, it still needs to be combined with traditional autopsy technologies for practical application.
The CT scanner used in this study had only 16 slices and was limited by low resolution, high background noise, and the inability to accurately display the morphology of injuries. However, it has been proven in practice that 16-slice CT is competent for many kinds of forensic cases and can meet the needs of forensic examinations through adjustment of the parameters. In addition, CT scanning in forensic cases does not require specialized knowledge or skills in clinical medical imaging. Most forensic practitioners with adequate clinical medical knowledge and accumulation of experience are fully capable of using CT to diagnose fatal lesions such as organ injuries, hemorrhage, and coagulation.
This article was originally released in the Chinese language in the Chinese Journal of Forensic Medicine.
Financial support and sponsorship
This work was supported by the Research Topic “Research on the Injury Mechanism of Complex Craniocerebral Injuries and the Comprehensive Diagnosis Methods of Forensic Medicine” (2018YFC0807203) under Project “Research on the Basic Theory of Forensic Medicine and Trace Inspection Science” of 2018 National Key R&D Program of China and was a Funded Project of Fundamental Research Funds for the Central Scientific Research Institutes (2016JB041).
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]