低剂量扫描与低浓度对比剂联合迭代重建CTA在颈部血管模型中的应用

目的 探讨低剂量扫描与低浓度对比剂联合迭代重建技术对颈部血管模型CTA检查的应用价值。方法 建立9个颈部血管模型，CT扫描采用管电压120 kV、管电流250 mAs，分别进行滤波反投影（FBP）重建和iDose3、iDose4、iDose5重建。采用不同管电压（80、100 kV）和管电流（200、250、300、350 mAs）进行两两组合扫描，进行iDose5重建。对图像质量和辐射剂量进行评价，并进行统计学分析。结果 120 kV 250 mAs图像iDose5重建的CNR优于FBP重建 （P<0.05）。不同扫描条件的iDose5重建图像与120 kV 250 mAs FBP重建图像的CNR和SNR差异均有统计学意义（P均<0.05），噪声差异均无统计学意义（P均>0.05）。与120 kV 250 mAs FBP重建图像比较，80 kV 200 mAs iDose5重建图像的CNR差异有统计学意义（P<0.05）；80 kV 200 mAs iDose5、80 kV 250 mAs iDose5、100 kV 350 mAs iDose5重建图像的SNR差异均有统计学意义（P均<0.05）。余扫描条件和重建方法图像的CNR、SNR两两比较，差异均无统计学意义（P均>0.05）。管电压不变时，iDose5重建的容积CT剂量指数（CTDIvol）、剂量长度乘积（DLP）、有效剂量（ED）随管电流的增加而增加；管电流不变时，iDose5重建的CTDIvol、DLP、ED随管电压的增加而增加。结论 低剂量扫描与低浓度对比剂联合迭代重建技术可获得高质量的CTA图像，且能够减低辐射剂量。

Application of low dose scanning and low concentration contrast media combined with iterative reconstruction CTA in neck vascular model

Objective To investigate the application value of low dose scanning and low concentration contrast media combined with iterative reconstruction CTA in neck vascular model. Methods Nine neck vascular models were established, and scaned with 120 kV tube voltage and 250 mAs tube current. The images were respectively reconstructed with filtered-back projection (FBP), iDose3, iDose4 and iDose5. Then all the neck vascular models were scanned among any two of following scanning conditions: Tube voltage of 80 kV or 100 kV, tube current of 200 mAs, 250 mAs, 300 mAs or 350 mAs. Then all the images were reconstructed with iDose5. The quality of the images and radiation dose were evaluated and analyzed statistically. Results CNR of iDose5 reconstruction was superior to FBP reconstruction in the condition of 120 kV 250 mAs (P<0.05). There was statistically difference in CNR and SNR between iDose5 in different scan conditions and FBP reconstruction in 120 kV 250 mAs (all P<0.05), and no difference in noise (all P>0.05). Compared with FBP reconstruction in 120 kV 250 mAs, CNR of iDose5 reconstruction in 80 kV 250 mAs had statistically difference (P<0.05), and SNR of iDose5 reconstruction in 80 kV 200 mAs, 80 kV 250 mAs, 100 kV 350 mAs had statistically difference (all P<0.05). CNR and SNR had no significant difference between any two of images obtained in remaining scanning conditions and reconstruction methods (all P>0.05). When tube voltage was constant, CT dose index-volume (CTDIvol), dose length product (DLP) and effective dose (ED) of iDose5 were increased with tube current. When tube current was constant, CTDIvol, DLP and ED of iDose5 were increased with tube voltage. Conclusion Low dose scanning and low concentration contrast media combined with iterative reconstruction can obtain high quality CTA images and reduce radiation dosage.