Flash序列低电压小儿肺CT扫描的可行性研究

目的：对三种不同管电压条件下的 Flash模式小儿肺C T图像质量进行评价，探讨低电压扫描的可行性。方法前瞻性分析93例患儿胸部双源CT Flash模式检查资料，按照不同管电压随机分为三组（组1：80kV ，34例；组2：100kV ，29例；组3：120kV ，30例）。两位放射科医师独立对图像质量采用4分制评分；记录每组有效 mAs、CTDlvol和DLP ，测量图像密度及噪声，计算信噪比（SNR）、有效辐射剂量（ED）。结果①三组图像质量得分〔（3．12±0．640）、（3.69±0．471）、（3．80±0．407）〕及S N R〔（4．25±0．945）、（5．46±1．790）、（5．88±1．665）〕在组1、2和组1、3间均有统计学差异（ P ＜0．05），组2、3间无统计学差异（ P ＞0．05）；②三组间的CTDlvol〔（1．05±0．056） mGy、（2．14±0．306） mGy、（2．63±0．697）mGy〕及ED〔（0．69±0．086） mSv、（1．36±0．250）mSv、（1．84±0．808）mSv〕均具有统计学差异（ P＜0．05）。结论100kV下CT Flash模式较80kV和120kV具有综合优势，在降低辐射剂量的同时能够保证高图像质量，对小儿肺部检查，尤其是小气道、肺间质等细微结构的观察具有显著临床意义。

Feasibility study on application of low tube voltage using Flash mode of DSCT in pediatric chest CT scan

Objective To evaluate the impact of three different tube voltages on image quality and radiation dosage in pe-diatric chest examination with Flash mode （subsecond high-pitch scan mode ,HPM=3 .0） of dual-source computed tomo-graphy （DSCT ） and to analyze the feasibility of the low-voltage CT scan .Methods A total of 93 patients undergoing chest scans with Flash mode of DSCT were prospectively enrolled in this study and divided into three groups equally ac-cording to different tube voltages （group 1 ：80 kV ,34 cases ;group 2：100 kV ,29 cases ;group 3 ：120 kV ,30 cases） . The image quality was evaluated by two radiologists using 4-point scores independently .Image attenuation and noise were measured .Signal-to-noise-ratio （SNR） and effective dose were calculated .The effective mAs ,CTDlvol and DLP were re-corded .Results The average image quality score of the three groups was （3 .12 ± 0 .640） ,（3 .69 ± 0 .471） and （3 .80 ± 0.407） .The average SNR was （4 .25 ± 0 .945） ,（5 .46 ± 1 .790） and （5 .88 ± 1 .665） .There were significant differences in score and SNR between group 1 and 2 ,group 1 and 3 （ P〈0 .05） .There was no difference between group 2 and 3 （ P〉0 .05） .The average CTDlvol was （1 .05 ± 0 .056） mGv ,（2 .14 ± 0 .306） mGv and （2 .63 ± 0 .697） mGv .The average ED was （0 .69 ± 0 .086） mSv ,（1 .36 ± 0 .250） mSv and （1 .84 ± 0 .808） mSv .There were significant differences in CTDlvol and ED among three groups （ P 〈0 .05） .Conclusion Flash mode of DSCT under 100 kV has comprehensive advantages in reducing radiation dose while ensuring high image quality ,and is of great clinical application value in the pediatric chest CT scan ,especially in the observation of fine structures ,such as small airways ,interstitial tissues ,and so on .