肥胖患者80kV不同级别迭代重建技术CTPA图像质量分析

CTPA image quality analysis of different level iterative reconstruction with 80 kV in obese patients

目的评估80kV条件下不同级别迭代重建技术对肥胖患者CT肺动脉造影(CTPA)图像质量的影响。方法收集临床疑似肺栓塞并行CTPA检查的肥胖患者40例,采用滤波反投影(FBP)及3个级别的迭代重建技术(iDose^1:20%IR/80%FBP;iDose^3:40%IR/60%FBP;iDose^5:60%IR/40%FBP)重建图像。测量图像的肺动脉主干、右肺上叶动脉及右肺下叶后基底段动脉CT值、噪声,计算并比较4组数据的噪声、SNR及CNR。结果 4组重建图像噪声、SNR及CNR差异均有统计学意义(P均<0.001),图像噪声两两比较差异均有统计学意义(P均<0.05);FBP组的SNR及CNR与iDose^3组和iDose^5组比较,差异有统计学意义(P<0.01)。结论与FBP比较,80kV联合不同级别IR技术可明显降低CTPA图像噪声,提高图像质量,并可进一步降低肥胖患者接受的辐射剂量。

Objective To assess the effects of different level iterative reconstructions （IR） on image quality of obese patients of 80 kV CT pulmonary angiography （CTPA）. Methods Forty obese patients with clinically suspected pulmonary embolism were examined with CTPA, filtered back projection method （FBP） and three IR levels （iDose1, 20% IR/80% FBP; iDose3, 40% IR/60% FBP; iDose5, 60% IR/40% FBP） to reconstruct images were used. The CT value of pulmonary artery trunk, upper lobe artery and lower lobe basal segment artery of right pulmonary were measured, and the image noise, SNR and CNR of four groups were calculated and compared. Results The image noise, SNR and CNR had significant difference in 4 groups （all P〈0.05）, and the image noise had significant difference between each two groups （all P〈0.05）, the SNR and CNR had statistical difference between FBP and iDose3, between FBP and iDose5 （P〈0.01）. Conclusion Compared with FBP, 80 kV combined with different level IR technologies can significantly decrease image noise and improve objective image quality in CTPA, the radiation dose that obese patients received can be reduced.