迭代重建技术对头颈部动脉CT血管成像图像质量和辐射剂量的影响

目的 探讨迭代重建技术应用于头颈部动脉CT中对血管成像图像质量以及辐射剂量的影响.方法 选择2014年4月至2016年3月期间在我院行头颈部CTA检查的100例患者,按照随机数表法分为A组和B组,每组50例.其中A组扫描参数120 kV、250 mAs,并采用滤波反投法进行重建,而B组扫描参数是100 kV、180 mAs,采用iDose4迭代重建技术,对比两组患者的CT容积剂量指数(CTDIvol)、剂量长度乘积(DLP)、噪声值、对比噪声比、图像质量、噪声情况.结果 在图像质量对比中,A组患者3分2例,4分12例,5分共36例;B组患者中4分10例,5分共40例,两组比较差异均无统计学意义(P>0.05);而在背景噪声评分中,A组患者1分2例,2分10例,3分38例,而B组患者2分8例,3分42例,两组比较差异均无统计学意义(P>0.05).此外,两组患者的噪声值其组织密度越高,则两者之间的差异也逐步缩小.而A组患者的DLP、CTDIvol分别为(1462.1±64.3)mGy·cm、(33.82±10.14)mGy,明显高于B组的(635.1±34.9)mGy·cm、(14.78±3.21)mGy,差异均有统计学意义(P<0.05).结论 对于需要行头颈部CTA检查的患者,可以采取迭代重建技术进行扫描,其不但可以获得较高的图像质量,同时也可以有效减低扫描过程中的辐射剂量,值得临床推广.

Effect of iterative reconstruction technique on image quality and radiation dose of head and neck artery CT angiography

Objective To investigate the effect of iterative reconstruction technique on the image quality and radiation dose in the CT of head and neck arteries. Methods A total of 100 cases with head and neck CTA examination, who admitted to our hospital from April 2014 to March 2016, were selected and divided into two the group A and group B according to random number table method, with 50 cases in each group. In group A, scanning parameters were 120 kV and 250 mAs, and the inverse filtering method was used for reconstruction. Scanning parameters in group B were 100 kV and 180 mAs, and iDose4 iterative reconstruction technique was used. CT volume dose index (CTDIvol), dose length product (DLP), the value of noise, contrast to noise ratio and image quality and noise were compared between the two groups. Results In the image quality comparison, there were 2 cases of 3 points, 12 cases of 4 points, 36 cases of 5 points in the group A;there were 10 cases of 4 points, 40 cases of 5 points in the group B;there was no significant differ-ence between the two groups in the image quality comparison (P>0.05). In the background noise score, there were 2 cas-es of 1 point, 10 cases of 2 points, 38 cases of 3 points in the group A;there were 8 cases of 2 points, 42 cases of 3 points in the group B;there also was no significant difference between the two groups in the background noise score (P>0.05). In addition, the higher noise density value of the two groups of patients, the more reduced difference between the two groups. CTDIvol, DLP of the group A were (1462.1 ± 64.3) mGy·cm, (33.82 ± 10.14) mGy, respectively, which were significantly higher than (635.1±34.9) mGy·cm, (14.78 ±3.21) mGy of the group B (P<0.05). Conclusion For the patients in need for head and neck CTA examination, iterative reconstruction technique can not only obtain higher image quality, but also can effectively reduce the radiation dose in the scanning process, which is worthy of clinical promotion.