前置呼吸模式在320排CT肺动脉双低成像的研究

Study on the clinical application of pre-breathing mode in double-low imaging of 320-slices CT for pulmonary artery

目的:探究前置呼吸模式在320排CT肺动脉双低成像。方法:前瞻性选取2021年7月至2022年9月柳州市人民医院收治的怀疑肺动脉栓塞(PE)行CT肺动脉造影(CTPA)检查的100例患者,采用随机数表法将其分为观察组和对照组,每组50例。对照组患者采取常规呼吸模式(达到阈值后启动呼吸口令,6 s后触发扫描),观察组采取前置呼吸模式(1或2 s后启动呼吸口令,达到阈值后触发扫描)。两组患者均采用320排CT行双低成像技术扫描,对比延迟时间、辐射剂量、主观与客观图像质量评分等指标差异。结果:观察组容积CT剂量指数(CTDIvol)、剂量长度乘积(DLP)、有效剂量(ED)及延迟时间均明显低于对照组,差异有统计学意义(t=76.230、30.225、12.282、7.088,P<0.05)。两组图像质量主观评分比较,观察组患者5分25例,4分23例,3分2例;对照组5分21例,4分26例,3分3例,图像质量主观评分的平均分组间比较差异无统计学意义(P>0.05)。观察组图像信噪比(SNR)、对比噪声比(CNR)明显低于对照组,噪声水平(SD)明显高于对照组,差异有统计学意义(t=25.441、23.886、11.426,P<0.05)。观察组右肺动脉干、右肺动脉分支、左肺动脉干以及左肺动脉分支CT值均较对照组高,差异均有统计学意义(t=2.256、2.225、2.042、2.277,P<0.05)。结论:前置呼吸模式能够有效提高CTPA图像质量,降低辐射剂量及对比剂用量,临床应用效果显著,值得借鉴。

Objective:To explore the clinical application value of pre-breathing mode in double-low imaging of 320-slices computed tomography(CT)for pulmonary artery.Methods:A total of 100 patients who underwent CT pulmonary angiography(CTPA)for suspected pulmonary embolism(PE)in Liuzhou People's Hospital from July 2021 to September 2022 were prospectively selected as the research subjects and they were randomly divided into observation group and control group,with 50 cases in each group.The patients of the control group adopted conventional breathing mode(the breathing password was activated after reaching the threshold,and the scan was triggered after 6 s),while the patients of the observation group adopted the pre-breathing mode(the breathing password was activated after 1 or 2 seconds,and the scan was triggered after reaching the threshold).Both two groups adopted double low-technique scan of 320 slices CT.The differences in delay time,radiation dose,the points of subjective and objective image quality,and other indicators were compared between the two groups.Results:The volume CT dose index(CTDIvol),dose length product(DLP),effective dose(ED)and delay time of the observation group were significantly lower than those of the control group(t=76.230,30.225,12.282,7.088,P<0.05),respectively.The comparison of the subjective points of image qualities between the two groups indicated that there were 25 cases with 5 points,23 cases with 4 points and 2 cases with 3 points in the observation group,and there were 21 cases with 5 points,26 cases with 4 points and 3 cases with 3 points in the control group.There was no significant difference in the averagely subjective points of image qualities between two groups(P>0.05).The signal-to-noise ratio(SNR)and signal to noise ratio(CNR)of the observation group were significantly lower than those of the control group,and the noise level(SD)of the observation group was significantly higher than that of the control group(t=25.441,23.886、11.426,P<0.05),respectively.The CT values of the artery trunk of right pulmonary,artery branch of right pulmonary,artery trunk of left pulmonary and artery branch of left pulmonary in the observation group were significantly higher than those in the control group(t=2.256,2.225,2.042,2.277,P<0.05),respectively.Conclusion:The pre-breathing mode can effectively improve CTPA image quality,and reduce radiation dose and the dosage of contrast agent,which clinical application effect is significant.It is worth learning.