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目的探讨不同后置滤过器对64排螺旋CT冠状动脉成像(CTCA)质量的影响。方法使用GE Light-Speed VCT机,采用120 kV,600 mA,0.35s/360°,层厚0.625 mm,pitch 0.2对Catphan 600模型进行扫描。采像后对原始图像分别进行不使用后置滤过器和使用后置滤过器C1、C2、C3重建,得到4组图像(NUC组、UC1组、UC2组和UC3组)。测量图像噪声(SD),计算对比噪声比(CNR)、信噪比(SNR)、调制传输函数(MTF)。统计分析采用单因素方差分析。结果 NUC组、UC1组、UC2组和UC3组的SD、CNR、SNR及MTF 50%差异均有高度统计学意义(均P<0.001),NUC组、UC1组和UC2组的MTF 10%差异无统计学意义(均P>0.05);UC3组与其余3组的MTF 10%差异有高度统计学意义(均P<0.01)。结论不同后置滤过器对CTCA图像SD、CNR、SNR和MTF的影响不同,可根据不同临床需要适当选择。
Objective To investigate the effect of different post-filter on the quality of 64-slice spiral CT coronary angiography (CTCA). Method The Catphan 600 model was scanned using a GE Light-Speed VCT machine at 120 kV, 600 mA, 0.35 s / 360 °, 0.625 mm layer thickness, and pitch 0.2. After the image was taken, the original image was reconstructed without using a postfilter and using a postfilter C1, C2 and C3 respectively to obtain four images (NUC group, UC1 group, UC2 group and UC3 group). Measure image noise (SD), calculate contrast to noise ratio (CNR), signal to noise ratio (SNR), and modulation transfer function (MTF). Statistical analysis using one-way analysis of variance. Results The differences in SD, CNR, SNR and MTF 50% in NUC group, UC1 group, UC2 group and UC3 group were highly statistically significant (all P <0.001). The MTF 10% difference between NUC group, UC1 group and UC2 group was no significant difference (All P> 0.05). The MTF 10% difference between the UC3 group and the other three groups was statistically significant (all P <0.01). Conclusion Different postfilters have different effects on SD, CNR, SNR and MTF of CTCA images, and may be appropriately selected according to different clinical needs.