CT最大密度投影重建在颅底骨折中的应用

The Diagnostic of Maximum Intensity Projection Reconstructions for Fracture in the Skull Base

目的 通过与螺旋CT多平面重建 (MPR)和表面掩盖法重建 (SSD)比较 ,探讨螺旋CT最大密度投影 (MIP)在颅底骨折中的临床应用价值 .方法 对 30例外伤颅底骨折患者进行螺旋CT轴位容积扫描 ,常规层厚 1～ 2mm ,重建间隔 1mm ,螺距为 1～ 1.5 ,原始轴位图像传输至工作站进行MPR、SSD、MIP等方法重建 ,分析比较各种技术、图像在骨折显示能力、骨折线连续性、碎骨片移位、塌陷程度和空间关系方面的优势 .结果 30例颅底骨折患者中 ,SSD显示14例 ,11例显示不全 ,5例未能显示 ;MIP显示 2 2例 ,8例显示不全 ;MPR结合轴位图像全部显示 .SSD在显示碎骨片明显移位的空间关系较MIP、MPR好 ,而MIP在显示微小骨折、结构细节和骨折连续性方面有优势 .结论 MIP重建图像显示颅底骨折效果良好 ,尤其在中颅窝显示微小骨折和有关孔、裂结构是否受累完整方面明显优于轴位CT和MPR、SSD重建 。

Objective To evaluate the diagnostic value of maximum intensity projection (MIP) reconstruction for fracture in the skull base by comparing MIP with multiplanar reconstruction (MPR) and surface shaded display (SSD).Methods 30 patients with truauma of the head,the base of skull were scanned with 1-2mm colimation, reconstruction interval 1～1.5mm and pith of 1～1.5.Original data obtained with transaxial images were transferred to workstation and processed with multiplanar reconstruction (MPR),surface shaded display (SSD) and maximum intensity projection(MIP).The images generated by these techniques were compared for fracture line,continuity, fragement displacement,collapse degree and space information and in conjunction with 2D images.Results In 30 cases,managed with SSD,14 were fully shown,11 were not entirely shown and 5 were negative.22 cases of 30 patients were shown with MIP, 8 were not fully displayed and no one negative.MPR depicted all fractures shown with 2D images.Above all,SSD was superior to MIP and MPR in displaying spatial relationship of those evident fragement displacement.However,MIP was more accurate in showing tiny small fracture, detailed structure and continuity,and could pick up fracture without displacement and overlooked by SSD,particularly for the fracture which occured in high density area of bone,Further more,MIP displayed the foramen in the middle cranial fossa.Conclusions MIP reconstruction is superior to SSD and MPR images in showing the fracture in the skull base, especially in showing tiny small fracture, and whether foramen involved. It's helpful to estimate whether nerve and blood vessel damaged nearby.