双能量非线性融合技术补救非峰值肺动脉CTA图像质量的应用价值

Application value of using dual energy CT with non-linear blending technique to improve the image quality of off-peak CTPA

目的:探讨双能量非线性融合(NLB)技术在补救非峰值肺动脉CTA图像质量(主观评分≤3分)中的应用价值。方法:回顾性搜集64例图像质量主观评分≤3分的肺动脉双能CTA图像(线性融合图像,LB组),将每例患者的原始图像采用NLB技术进行后处理,获得非线性融合图像(NLB组)。比较两组图像上7支肺血管(肺动脉主干、右肺动脉、左肺动脉、左肺上叶动脉、左肺下叶动脉、右肺上叶动脉、右肺下叶动脉)、栓子及背部肌肉的CT值及其标准差(SD)、信号噪声比(SNR)、对比噪声比(CNR)和图像质量主观评分。主观评分采用5分法,≤3分为非峰值图像。结果:CT显示肺动脉栓塞31例。NLB组7支肺血管CT值、SNR及CNR较LB组提高(P<0.05)。栓子平均CT值NLB组低于LB组,NLB组栓子CNR较LB组升高(P<0.05),而NLB组血管层面背部肌肉平均CT值和SD与LB组相比,差异无统计学意义(P>0.05)。NLB组主观评分高于LB组,主观评分提高0.53分(P<0.05)。结论:NLB技术可提高图像质量并增强肺栓子与血管对比度,补救非峰值肺动脉CTA图像。

Objective：To investigate the application of non-linear blending technique with dual energy CT to improve the image quality on off-peak CTPA with the subjective score 43. Methods： The CT images of 64 patients undergone contrast-enhanced dual energy CT of chest were collected, the images were defined as linear blending group, their subjective score was 43 for image quality. The CT raw data of each patient were post-processed with non-linear blending technique. Therefore,images were divided into linear blending （LB） group and non-linear blending （NLB） group. The contrast image quality score,CT value and SD,SNR and CNR of 7 pulmonary arteries including pulmonary artery trunk, right pulmonary artery, left pulmonary artery, left upper lobe artery, left lower lobe pulmonary artery, right upper lobe pulmonary artery and right lower lobe artery,embolus and muscles at the back of chest were measured and calculated, as well as the subjective scoring of image quality was performed. Using 5 grade for the scoring,and 43 was judged as off-peak image. Result：31 ea- ses showed pulmonary embolism （PE） on CTPA. The CT values, SNRs and CNRs of the 7 pulmonary arteries in NLB group were improved when compared with that of LB group,with significant statistic difference （P〈0.05）. The mean CT value of pulmonary embolus in NLB group was lower than that of LB group, and the CNR of embolus in NLB group was higher than that of LB group （P〈0.05）. The mean CT value and SD of the muscles at the back of chest in NLB group had no statistically significant difference when compared with that of LB group （P〉0.05）. The subjective image score of NLB group increased 0.53 when compared with that of LB group （P〈0. 05）. Conclusion： The image quality could be improved by NBL technique,as well as the contrast of pulmonary embolus and artery could be enhanced, thus,the off-peak CTPA images could be rectified.