CT三维重建技术对肩胛骨骨折的诊断价值

Three-dimensional surface shaded display and volume rendering techniques of CT in diagnosis of scapular fractures

目的探讨螺旋CT三维表面遮盖法重建(surfaceshadeddisplay,SSD)及容积重建技术(volumerenderingtechnique,VRT)对肩胛骨骨折的诊断应用价值。方法使用SIEMENSPLUS4螺旋CT机对20例肩胛骨骨折患者进行扫描,全部数据输入工作站进行SSD及VRT处理,并与X线、二维CT(2DCT)检查结果进行对照分析。结果2DCT扫描的结果经临床与手术证实为临床诊断的重要依据,经统计学分析,X线检查及SSD的诊断准确率分别为94.44%和97.78%,假阴性率分别为17.65%和7.84%,X线检查的假阳性率为0.76%;VRT诊断正确率为100%。SSD、VRT检出骨折创伤的数量与X线、2DCT的结果差异无显著性意义,但是显示损伤的质量优于X线和2DCT。术后对8例进行3DCT复查,VRT能立体显示术后肩胛骨骨质及内固定物的形态与结构。结论螺旋3DCT是诊断肩胛骨骨折的有效手段,可指导手术计划的制定和内固定物的选择,应作为诊断复杂性肩部骨折的首选方法。VRT对骨折术后内固定物的位置及复位效果的判断有较高的应用价值。

Objective To evaluate the value of three-dimensional surface shaded display (SSD) and volume rendering technique(VRT) in diagnosis of scapular injury. Methods Twenty patients of scapular fractures, who were 15 males and 5 males with an average age of 34 years, were examined with SIEMENS PLUS 4 helical CT. Images were reconstructed in workstation with three-dimensional SSD and VRT, and then analyzed and compared with X-ray and 2D CT images. The regions of interesting consisted of acromion, coracoid process, glenoid cavity, supraspinous fossa, scapular spine, infraspinous fossa, lateral margin, medial margin and inferior angle of scapula. All of imagings were evaluated by two experienced radiologists with double blind method. Results 2D CT findings were clinically or operatively confirmed, and also taken as an evaluative standard to analyze the diagnostic rates of the X-ray, SSD and VRT in this study. The positive rates of diagnosis in plain X-ray and SSD were 94.44% and 97.78%, and the false negative rates was 17.65% and 7.84% respectively; the false positive rate of diagnosis of plain X-ray was 0.76%; the positive rate of diagnosis of VRT was 100%. The difference between plain X-ray, 2D CT, SSD and VRT was not statistically significant for scapular fractures, but the quality of imaging to display the fracture details of 3D CT was the best, while 3D CT might obtain the most objective view of scapular fractures. Eight cases of scapular fractures were examined again post-operatively, the reconstructed images of 3D CT displayed the structure of scapular fractures clearly. VRT could show the contour of scapula and position of the internal fixation, as well as the effect of reduction after operation and the healing status of scapular fractures. Conclusion SSD and VRT of spiral CT are effective methods in diagnosing scapular injury. The images of SSD and VRT of spiral CT may provide exact guidance to preoperative protocol and internal fixation. For complicated scapular fractures, these two techniques could be regarded as imaging techniques of choice. Furthermore, VRT provides more important information to apply the internal fixation devices and assess the result of surgical reduction.