The Value Of Multi-slice Spiral CT For Diagnosing Rib Fracture In Forensic Applications

Objective 1.By comparing the sensitivity and detection rate of rib fracture between curved planar reconstruction(CPR)and conventional multi-plane recombination(MPR),to evaluate the application value of CPR in forensic medicine and provide accurate and objective evidence for forensic injury.2.To explore MSCT optimal examination time window for patients with occult rib fracture,and provide objective evidence for forensic injury.Methods A total of four hundred cases who had the trauma in the chest were analysed retrospectively.All patients underwent MSCT during the first week after trauma.Totally four hundred cases who were assigned randomly to two groups,A and B,respectively.The images of all cases were reconstructed by a software(CT Bone Reading software)to produce CPR and MPR of the ribs.The images of these patients were reviewed by two radiologists.One radiologist assessed group A by CPR and group B by standard MPR.Another radiologist assessed group A by standard MPR and group B by CPR.All results of the fractures detected by the two readers were compared with the gold standard,which was established by two senior radiologists.The X~2 test was used to compare the difference of the fractures diagnosis sensitivity between the CPRs and the standard MPRs.The difference of reading time for the CPRs and the standard MPRs were compared by the T test.Totally 105 patients were selected from the above 400 patients for further study.They were examined in the first week after trauma and re-examined in different time windows by MSCT.The quantities of occult rib fractures in the first examination were compared to those in re-examinations.Results Fourteen cases were excluded from the final evaluation for program failure.Totally 386 cases were enrolled in the final study.The standard of reference showed that there were 178 patients with fracture in the 386 patients and 633 rib fractures in 178 patients.The detection ensitivity of rib fracture by CPR was more higher than MPR,with 87.520%(554/633)and 79.147%(501/633),respectively.The difference of the detection ensitivity of rib fracture was statistically significant(P<0.001).No statistically significant were found on a per-patient basis(P=0.275)and a per-rib basis(P=0.077).The different reading time for every case between CPR(33.438±1.417 s)and MPR(66.730±3.450 s)had statistically significant(P<0.001).A further study of 105 patients selected from 400 patients found that the quantities of occult rib fractures at different inspection time windows were mostly different.There was no statistically significant between the quantities of rib fractures in the first week and the second week,the first week and the sixth week later,the fourth week and the fifth to sixth weeks(P>0.05).There was statistically significant between the quantities of rib fractures in the first week and the thrid to sixth weeks,the second week and the third to sixth weeks,the third week and the fourth to sixth weeks(P<0.05).Conclusion 1.Compared with the standard MPR,using CPR can shorten the reading time and increased overall sensitivity of the diagnosis rib fractures,CPR can be used in the forensic identification of chest trauma with rib fracture.2.The result of the study imply that the fourth to sixth week is the optimal time window of MSCT examination in the occult rib fracture.