低辐射剂量结合低对比剂用量在肝脏占位CT扫描中的应用研究

Application of low radiation dose in combination with low dose contrast medium in CT scans of hepatic lesions

目的:探讨三维自适应迭代剂量降低(adaptive iterative dose reduction 3D,AIDR 3D)迭代重建技术结合低对比剂用量在肝脏病灶扫描中的应用。方法:前瞻性地将60例肝脏占位患者随机分为两组,每组30例,A组(常规组)采用滤过反投影(filtered back projection,FBP)重建+常规对比剂用量(1.5 mL/kg),B组(双低剂量组)采用AIDR 3D重建+低对比剂用量(1.0 mL/kg)。对两组图像主观噪声、总体质量及是否达到诊断要求,按1~5分(1分最差,5分最优)予以评分。定量计算两组图像的有效辐射剂量、图像噪声、信噪比(signal-to-noise ratio,SNR)、对比度噪声比(contrast-tonoise ratio,CNR)。计量资料采用完全随机设计的独立样本t检验及秩和检验,计数资料采用完全随机设计的非参数检验(Mann-Whitney test)。结果:B组有效剂量较A组降低约32.1%;主观评估中,B组图像质量评分与A组相似,差异无统计学意义(P>0.05);客观评估中,B组图像噪声低于A组,CNR与SNR高于A组(P<0.05)。结论:低对比剂剂量结合AIDR 3D重建技术,在降低CT辐射剂量及减少造影剂用量的条件下,仍可得到符合诊断标准的图像。

Objective： To investigate the image quality and radiation dose of adaptive iterative dose reduction 3D （AIDR 3D） iterative reconstruction technique and low dose contrast medium in enhanced CT scans of focal liver lesions. Methods： A total of 60 patients underwent hepatic enhanced CT scans were randomly divided into two groups. Group A adopted filtered back projection （FBP） reconstruction and conventional dose contrast medium （1.5 mL/kg）, and group B adopted AIDR 3D reconstruction and low dose contrast medium （1.0 mL/kg）. Qualitative ranking of noise, image quality and whether meet the requirements of diagnosis were graded [a scale of 1-5 （1 worse, 5 （best）]. The radiation dose, imaging noise, signal-to-noise ratio （SNR）, contrast-to-noise ratio （CNR） were quantitatively measured. Results： The effective dose （ED） in group B decreased 32.1% compared to group A. In group B, the score of image quality was similar to group A （P〉0.05）, the image noise was lower, CNR and SNR were higher compared with group A （P〈0.05）. Conclusion： Low dose contrast medium combined with AIDR 3D reconstruction technology can be used for CT scans of the hepatic lesions.