矫形金属植入物CT扫描技术的初步经验

Preliminary Experience of Displaying Metallic Orthopedic Implants by Multi-detector Row CT

目的该项研究通过改变矫形金属植入物MSCT扫描和重建方案的实验,以获得影像诊断质量满意的最佳检查方案。方法取尸体标本采用MSCT扫描,扫描野25cm;观查野10cm;扫描时间1.0s其它参数分别为(80;20kV。80;400mA。Pitch值1.75;0.75。扫描层厚5;0.5mm。影像数据取60%叠加重组。进行不同摆位和参数的试验。结果改变摆位或扫描架角度,可将金属植入物在扫描层面的量减至最小,降低了线束硬化伪影。提高kVp,mAs值,减小扫描和重组层厚以及Pitch值,可提高信噪比,两者均可抹消部分金属伪影。结论MDCT取上述实验的最佳检查方案可显著抹消部分金属伪影。

Objective：Various acquisition and reconstruction Protocols of multi-detector row CT （MDCT） were studied in order to find out an optimal protocol to improve the image quality by diminishing metallic artifacts. Methods： One human corpse were used as the experimental subject and scanned with MDCT,included SFOV：25cm;FOV 10cm;rotation time 1s. The other parameters were as follows： 80/120kV; 80/400mA; Pitch 1.75/0.75;and slice thickness 5/0. 5mm. The data acquired were reconstructed with 60% overlapping. Various position and scan parameters were used. Results： The volume of metallic implants within the scan thickness could be diminished to the least by adjusting the position of the corpse or gantry angle, reduce of the beam hardening artifacts caused by metallic implants could be achieved. The signal-noise ratio could be increased by reducing the scan and reconstruction thickness and pitch value,increasing the KVP and mAs,then diminishing the beam hardening artifact. Conclusion： Marked diminution of metallic artifacts could be acquired by using the optimal protocol obtained by the above-mentioned experimental MDCT acquisitions.