MSCT参数优化和图像质量的相关性研究

目的探讨多层螺旋CT（MSCT）诸扫描参数对图像质量的影响，以进一步提高MSCT图像的质量。方法固定扫描条件，分别对两种不同密度材料的质量控制体模进行扫描。在质量控制体模的左、中、右各选取1个431．43mm2的感兴趣区（ROI），改变其中某个扫描条件（如层厚、电压、曝光量、螺距），对质量控制模各扫描10次，计算CT值（X±SD），并比较各条件下两种质量控制体模的CT值。结果在固定扫描条件下，随曝光量、层厚的增加，CT图像对应各材料的平均CT值变化不明显，而SD明显减小；随着管电压的升高，CT图像对应各材料的平均CT值和SD明显减小；随着螺距的增大，CT图像对应各材料的平均CT值无明显变化，而SD增加较为明显。结论CT图像质量与扫描参数密切相关，并且各扫捕参数之间既相互影响，又相互制约。

Relevant Study of MSCT Parameter Optimization and Image Quality

Objective Scanning parameters of multi-slice CT （MSCT） on image quality are investigated to further improve the quality of the MSCT image. Methods On a fixed scanning condition, the two quality control modules with different density materials, of which a region of interest （ROI： 431.43 mm2） is selected respectively in the left, middle, right, are scanned. CT values （X±SD） of the two different modules are measured by 10 times scanning when only one condition is changed （such as layer thickness, voltage, exposure amount, pitch）, then are compared. Results When only exposure amount and layer thickness increase, the mean CT value has no obvious change, but SD decreases obviously; as the tube voltage increases, the mean CT value and the SD significantly decrease; with increasing of spiral pitch, the mean CT value gets no obvious change, but SD increases obviously. Conclusion Scanning parameters have close relationship with CT image quality, and parameters changes also would effect each other.