The Application Value Of 64-slice Spiral CT Post-processing Technique In Forensic Identification Of Sacral Wall Fractures

Objective:To explore the application value of multi-slice spiral CT(MSCT) and post-processing technique for orbital fracture diagnosis and medicolegal expertise,observe the effect of orbital fat space change after trauma on orbital fracture diagnosis,and provide reliable and detailed evidence for the medicolegal expertise.Methods:MSCT scanning images of 150 patients with orbital fracture from the hospital between January of 2011 and July of 2012 were collected. Their orbit and surrounding soft tissue injury status were examined preoperatively under CT scans,MPR and VR afterprocessing. All images were diagnosed and evaluated by 3 doctors from CT department through double-blind method. The final diagnosis result was achieved based on the summary of these doctors’ diagnosis result. Besides, the evaluation on the diagnosis effect of the conventional axial CT and post-processing technique on the orbital fracture was carried out. Besides, it collected the CT value of the inner muscular cone and extraconal fat space of 61 patients’(with monocular orbital fracture) uninjured eye and injured eye, and then combined the data of uninjured side and injured side of the extraconal fat space, so as to conduct the statistics analysis and evaluate the influence of the trauma on the orbital adipose tissue. To simplify the sample parameters, the initial screening conditions are as follows:(1) select the patients with the monocular orbital fracture, and compare the change status between the uninjured and injured sides of the fat space, and reduce the influence of the external factors and individual difference;(2)remove the examinees at the age of below 18 and above 70, and select the adults for this experiment, and reduce the influence of the age factors as possible.Results:1、The fracture sites found were as follows:superior wall of the orbit(13 places),inferior wall(66), medial(142),and lateral wall(9).There were 157 fractures shown by CT axial image. After checking through the post-processing technique, 230 fractures were diagnosed. The conventional CT axial image and the post-processing technique image had obvious statistics difference(χ2=46.34, p<0.01). 2、The comparison on extraconal CT value between the uninjured and injured sides had significant statistical meaning(t=9.70,p<0.01). 3、There were 137 patients with monocular orbital fracture(91.3%), 13 patients with binoculus orbital fracture(8.7%);142 patients with burst fracture(87.1%), 18 patients with composite fracture(11%), 3 patients with direct fracture(1.8%);140 patients with fresh fracture(93.3%), and 10 patients with old fracture(6.7%).Conclusion:1、Orbital wall fracture can be exactly diagnosed by 64 thin layer spiral CT and the post-processing technology, which has an important practical value in medicolegal identification.2、The change of the post-trauma orbital fat space can assist diagnosing the orbital fracture. 3、Most orbital injury is monocular orbital fracture and burst fracture, which is related to the special orbital structure. MSCT and post-processing technique can identify the fresh and old fracture, and correctly distinguish the fracture and anatomic variation status. It is regarded as the first choice to identify the orbital fracture.