| Background and Objective:Under the current international situation, blast injuries of war, terrorist attacks are important morbidity and mortality factors for the victims. Therefore, early diagnosis and treatment of blast injury are needed. However, blast injury’s characteristics of complex and invisibility restricted the early diagnosis. At present, Study on the blast injury were mainly concentrated in the mechanism of injury and surgical treatment, and the diagnosis of the injury and imaging diagnosis of the less involved. But in the war time, the poor condition of battlefield will restrain the evaluation of serious level, which may further delaying treatment. Thus, a simple, non-invasive, repeatable, and practical screening methods applied to the blast injury’s early diagnosis are required.Ultrasound technology has been in great development and are widely applied to trauma assessment, which owns advantages of lightweight, flexible and safe. Recently, real-time shear wave elastography(SWE) also made some achievements in the clinical evaluation of abdominal organs trauma, suggesting that SWE is potential for the clinical diagnosis in explosion injury.This study envisaged on the basis of the establishment of an animal model of abdominal blast injury, the study focuses on the following three aspects: 1.To discussion liver conventional ultrasound imaging characteristics and clinical significance of abdominal blast injury. 2. To explore the role of SWE in evaluating liver injury of abdominal blast injury.3. To discussion clinical significance of Conventional ultrasound combined with real-time shear wave imaging technology on dynamic observation of abdominal blast injuryMethods:1. Experimental groups: First, rabbits were randomly divided into blast injury group(n=45) and non-blast injury group(n=5). Then according to the distance between detonator and rabbits, the blast injury group were randomly divided into three groups: slight blast injury group(SBI, distance = 15 CM, n = 15), moderate injury group(MBI, distance = 15 CM, n = 15), heavy injury group(HBI, distance = 15 CM, n = 15), the non-blast injury groups were pathological control. In MBI group, 10 rabbits were sacrificed for immediate examination after the knock, while the other 5 were observed at multiple different time points. Abdominal blast injury model: After completion of the examination, the rabbits were placed in specially prepared homemade injury platform. According to the experimental distance requirements placed 8 # paper electric detonators, make detonators and rabbit costal margin midpoint in the same level. The shock sensor was placed on both sides of the rabbit liver monitoring abdomen shock pressure peaks and detonated detonators for rabbits injury.2. The ultrasonic diagnostic apparatus(Aixplorer, French) with the probe SL15-4 and 4 ~ 15 MHz frequency, were used for scanning liver morphology and obtaining sonographic maps of internal structure. Based on automatic biochemical analyzer and chemiluminescence immunoassay analyzer serum alanine aminotransferase(ALT), C-reactive protein(CRP) and interleukin-8(IL-8) levels before and after blast injury. The results were analyzed using a paired samples t-test and ANOVA statistical methods.3. The real-time shear wave elastograghy(SWE)(Aixplorer, French) technology was used for automatic detection of liver Young’s modulus values(BOX) in SBI, MB and HBI groups before and after blast injury, and the 5 time detection BOXs’ average value was as the mean elasticity values of rabbit liver(Kpa). The result of elasticity was analyzed using a paired samples t-test and ANOVA statistical methods. The BOX and serum ALT results were analyzed with Pearson correlation analysis.4. To get liver sonographic maps of internal structure and evaluate BOX and serum ALT, CRP and IL-8 levels, routine ultrasound combined with SWE technology were applied in MBI rabbits at 30 minutes, 2 hours, 4 hours, 6 hours after blast. The data were analyzed using comparative non-parametric test analysis.Results:The shock wave sensor test results show that HBI group: 5 CM distance from the exploder, the peak pressure was 1408.7 ± 256.7 k Pa; MBI group: 10 CM distance from the exploder, the peak pressure was 523.3 ± 184.3 k Pa; SBI group: 15 CM distance from the exploder, the peak pressure is 187.4 ± 75.6 k Pa. In the HBI group, liver capsule rupture, obvious subcapsular blood clot were observed, and most of the liver parenchyma injury sites were more than 3, additionally, 5 rabbits were died immediately. In MBI group showed less liver subcapsular blood clot, and smaller liver parenchyma damage area, mostly only 1-2 liver injury sites, no rabbits were died immediately after injury, while 3 were died during the test. In SBI group, the rabbites were mainly exhibited with less hepatic subcapsular blood clot, and no significant liver parenchymal damage and rabbits death. Histopathological examination showed that obvious liver cell edema and necrosis and inflammatory cells infiltration were observed in HBI group; liver cell edema, inflammatory cells infiltration and liver blood sinus expansion and hemorrhage were observed in MBI group; while the SBI group were merely exhibited with mild liver cell edema and ecchymosis.1. Conventional ultrasound scanning showed that the structure and morphology of liver were normal before injury, while with the increasing injury degree, the damage degree of liver capsule rupture and liver parenchymal uneven diffuse echo range were increased. In the MBI group, the liver parenchyma were mainly exhibited with uneven echo and partial hepatic subcapsular hematoma; while the HBI group also showed intrahepatic effusion, liver parenchymal rupture and intrahepatic pneumatosis etc. characteristic sonographic. we found after blast injury of liver disease routine liver ultrasound and physical examination results in the severe group of scanning results are in agreement, but the pathology examination showed mild liver group has changed pathology. Comparison with the before injury, the immediate serum ALT levels were increased in the three groups after injury(p < 0.05), and with the knock aggravation, the serum ALT levels were gradually increased(p < 0.05); meanwhile, the immediate serum CRP levels also increased significantly in HBI and MBI groups after injury(p < 0.05), but the serum IL-8 level was no significant change(p > 0.05).2. SWE examination showed that compare to the before injury, the three groups’ immediate liver BOX after injury were increased(p < 0.05), and increased with the blast injury’s aggravation(p < 0.05). In addition, Pearson correlation analysis showed that the liver BOX were significantly positive correlated with serum ALT levels(r = 0.836, p < 0.001).3. MBI2 group’s dynamic study found that with time passing, the hepatic parenchymal echo was gradually increased, and the diffuse heterogeneous echo range and hepatic parenchyma effusion were also increased, as well as the liver BOX and serum ALT, CRP, IL-8 levels etc.(p < 0.05).Conclusions1. Our results suggests that liver Blast injury conventional ultrasonography has a complicated and diverse characteristics, conventional ultrasound is sensitive in moderate and heavy liver injuries’ diagnosis after blast, while it is difficult to make an effective evaluation in slight ones.2. SWE is sensitive for the diagnosis of slight liver injury after blast in rabbits, which may be a new way for blast injuries’ evaluation in the future.3. Conventional ultrasound combined with SWE technology can dynamically, timely and effectively evaluate the early liver damage, and provide more convincing evidence for the early clinical diagnosis. |
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