基于原始数据的迭代重建技术在鼻部外伤 CT 扫描中的应用

目的：探讨基于原始数据的迭代重建（SAFIRE）技术在鼻部外伤性病变中的应用价值。方法鼻部外伤67例行CT 平扫，分别用 FBP 和 SAFIRE（强度1～5级）重建，对6种重建图像平均 CT 值、噪声、信号噪声比（SNR）、对比噪声比（CNR）、主观评分及病变检出情况对比分析。结果与 FBP 重建相比，SAFIRE（1～5级）重建后，噪声分别降低20．4％、31．4％、39．7％、46．5％、57．2％；SNR 分别提高33．3％、54．7％、75．4％、87．4％、101．4％；CNR 分别提高23．0％、36．4％、57．7％、87．4％、106．5％，差异有统计学意义（P＜0．05）。图像主观评分 SAFIRE‐1和 SAFIRE‐5图像评分低于 FBP ，SAFIRE2‐4高于 FBP 重建， SAFIRE‐3评分最高，但6种重建图像的病变检出率一致。结论 CT 平扫结合 SAFIRE 重建技术在外伤性鼻部扫描中能有效降低图像噪声及提高图像质量，具有潜在降低扫描剂量的作用。

Application of reconstruction technique in the CT scan of nasal traumas

Objective To evaluate the value of the SAFIRE reconstruction technique for the nasal traumatic lesions .Methods Six‐ty‐seven patients with nasal traumas were scanned by the orbital scan and were reconstructed with FBP and SAFIRE (strength grade 1 to 5) respectively .Then a comparative analysis for six kinds of reconstructed images were conducted on the average CT value ,noise ,signal to noise ratio (SNR) ,contrast to noise ratio (CNR) ,subjective scoring and lesion detection .Results Compared with reconstruction by FBP , SAFIRE (strength grade 1 to 5)reconstruction ,for the noise ,decreased to 20 .4% ,31 .4% ,39 .7% ,46 .5% and 57 .2% respectively ;For the SNR ,increased to 33 .3% ,54 .7% ,75 .4% ,87 .4% and 101 .4% respectively ;For the CNR ,it also increased to 23 .0% ,36 .4% ,57 .7% , 87 .4% and 106 .5% respectively ;The difference was statistically significant (P< 0 .05) .For the images of SAFIRE‐1 and SAFIRE‐5 ,the image subjective scoring was lower than that by FBP ;for the images of SAFIRE‐2 and SAFIRE‐4 ,the image subjective scoring was higher than that by FBP ;and SAFIRE‐3 had the highest score .But for the rate of lesion detection ,all the images were the same .Conclusion CT scan combined SAFIRE reconstruction technique can decrease effectively the noise and increase the image quality in the traumatic nasal scan , as well as has a potential effect to decrease the scan dose .