Application Of Ultrasound In Noninvasive Autopsy Of Traffic Accidents

As one of the most important and classical examination method in forensic medicine,autopsy has been widely used in the cases of violent deaths for determining the cause of death,discovering evidence of injury,and restoring the truth of the incident.However,autopsy is destructive to the remains,which is generally resisted by the families of the victims,especially in the traffic accident.Autopsy table test is sued as alternative in such situations.However,the information that could be obtained through this method is limited to superficial wound,skin contusion or severe fracture,leading to the loss of massive important information such as incomplete fracture,visceral injury,and internal bleeding.The evidence obtained therefore may not be complete and confirmed,and as a result,the judgement of these cases may not be fair and objective.To improve this situation,in2009,The Army Military Medical University takes the lead in 64-slice CT scanning and 3D reconstruction technology to get the injury details of corpse,and has gained some achievements in this field.Because CT is expensive,huge equipment and complex maintenance,it can not move at will.It can only send the remains to the designated place for scanning and analysis.It has many inconveniences in the specific use process.Therefore,exploring a new and portable noninvasive method is the dream of legal examiner for many years.Similar to X-ray and CT,ultrasound can observe tissues,observe organs,hypoderm,skeleton and even nerve structure,and has the advantages of low cost,convenience,high efficiency,simple operation and so on,and is not limited by place.Therefore,we first put forward the application of portable ultrasound to noninvasive dissection,and use animal trauma model to carry out ultrasonic noninvasive anatomical study.In this experiment,animal models of impact injury,pneumothorax and fracture were established with New Zealand rabbits.After death,ultrasound diagnosis was carried out,and the feasibility and application value of the noninvasive autopsy method carried out by ultrasound are tested.The research methods and conclusions are as follows:1)animal model: healthy New Zealand rabbits placed homemade vertical impact machine in BIM-1 type steel pipe,steel ball weight 270 g,50mm diameter or weight 856 g,diameter 40 mm,free fall in the height of 1.5m,A typical animal model of thoracoabdominal impact injury and a lower limb fracture model were set up against the chest,abdomen and lower extremities of rabbits.10-25 ml air is injected into the chest to simulate pneumothorax.Stab the liver with a scalpel and simulate a sharp injury to the abdomen.2)Noninvasive ultrasound examination was performed on the thoracic and abdominal and skeletal muscle systems.The results can meet the requirements of the autopsy of some traffic accident cases.The main results are as follows: ultrasound can rapid detection of fracture,sensitivity to non displaced fractures of the ribs are higher,but also can determine the fracture damage,muscle tissue around hematoma;The contour of the heart,the demarcation of each chamber,and the thickness of the cardiac muscle layer can be observed under the standard section.Occurrence of hemopneumothorax,heart is unclear.It has high diagnostic accuracy for pleural effusion,intrahepatic hemorrhage and pericardial blood,and can estimate the amount of bleeding roughly.The metallic foreign bodies embedded in the viscera can be detected under ultrasound,and there are strong echoes scattered in the parenchymal echo after the gas is mixed into the liver.By using the animal model to verify the application value of noninvasive ultrasound in anatomy,the results showed that ultrasonic can detect the experimental animal of the chest and abdomen and lower extremity injury,exploration results can meet part of the traffic accident in forensic medicine inspection requirements,proof of noninvasive ultrasound anatomy method is feasible and meaningful.