应用iDose^4软件对低剂量胸部CT增强扫描图像质量的影响

Evaluation on impact of iDose^4 on dose reduction and image quality of low dose contrast-enhance chest CT

目的评价将iDose4迭代重建(IR)技术用于胸部低剂量增强扫描的可行性。方法选取71例体质量指数(BMI)正常(18.5≤BMI<25.0kg/m2)且接受胸部CT增强扫描的患者,随机分为A组(120kVp,100 mAs)、B组(80kVp,100mAs)、C组(120kVp,50mAs),分别采用iDose4 IR技术和FBP进行重建,记录各组的噪声、SNR、CNR和有效剂量(ED)。按1～3分评价各组总体图像质量,并对3组结果进行比较。结果比较同一个患者的FBP和IR图像,IR技术明显降低了图像的噪声,提高了图像的SNR、CNR。B、C组IR后的图像噪声、SNR和CNR与A组FBP图像比较差异均无统计学意义(P均>0.05)。B、C组IR后的图像总体质量与A组FBP重建图像质量差异无统计学意义(P>0.05)。结论运用IR技术进行低剂量胸部CT增强扫描可获得满足诊断要求的图像。

Objective To evaluate the feasibility of using iterative reconstruction （IR） algorithm （iDose4） in low dose contrast-enhanced chest CT. Methods Seventy-one patients with normal body mass index （BMI, 18.5--25.0 kg/m2） un- derwent contrast-enhanced chest CT. The patients were randomly assigned into 3 groups： group A, 120 kVp/100 mAss group B, 80 kVp/100 mAss group C, 120 kVp/50 mAs. All images were reconstructed using conventional filtered back projection （FBP） and IR. The mean image noise, SNR, CNR and effective dose （ED） with each protocol were assessed. Image quality were graded （scale.. 1--3） and compared among 3 groups. Results For the same patient, IR significantly de- creased the mean image noise, improved SNR and CNR compared with FBP. The mean image noise, SNR and CNR using IR in group B and C were improved or comparable to those in group A using FBP （all P〉0.05）. No significant difference was found in subjective image quality between groups B and C using IR, nor with group A using FBP （P〉0.05）. Conclu- sion It is feasible to obtain images qualified for diagnosis using IR in low dose contrast-enhanced chest CT examination.