Symons Rolf, Pourmorteza Amir, Sandfort Veit, Ahlman Mark A, Cropper Tracy, Mallek Marissa, Kappler Steffen, Ulzheimer Stefan, Mahesh Mahadevappa, Jones Elizabeth C, Malayeri Ashkan A, Folio Les R, Bluemke David A
From the Department of Radiology and Imaging Sciences, National Institutes of Health Clinical Center, 10 Center Dr, Bethesda, MD 20892 (R.S., A.P., V.S., M.A.A., T.C., M. Mallek, E.C.J., A.A.M., L.R.F., D.A.B.); Siemens Healthcare, Forchheim, Germany (S.K., S.U.); and Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Md (M. Mahesh).
Radiology. 2017 Dec;285(3):980-989. doi: 10.1148/radiol.2017162587. Epub 2017 Jul 28.
Purpose To investigate whether photon-counting detector (PCD) technology can improve dose-reduced chest computed tomography (CT) image quality compared with that attained with conventional energy-integrating detector (EID) technology in vivo. Materials and Methods This was a HIPAA-compliant institutional review board-approved study, with informed consent from patients. Dose-reduced spiral unenhanced lung EID and PCD CT examinations were performed in 30 asymptomatic volunteers in accordance with manufacturer-recommended guidelines for CT lung cancer screening (120-kVp tube voltage, 20-mAs reference tube current-time product for both detectors). Quantitative analysis of images included measurement of mean attenuation, noise power spectrum (NPS), and lung nodule contrast-to-noise ratio (CNR). Images were qualitatively analyzed by three radiologists blinded to detector type. Reproducibility was assessed with the intraclass correlation coefficient (ICC). McNemar, paired t, and Wilcoxon signed-rank tests were used to compare image quality. Results Thirty study subjects were evaluated (mean age, 55.0 years ± 8.7 [standard deviation]; 14 men). Of these patients, 10 had a normal body mass index (BMI) (BMI range, 18.5-24.9 kg/m; group 1), 10 were overweight (BMI range, 25.0-29.9 kg/m; group 2), and 10 were obese (BMI ≥30.0 kg/m, group 3). PCD diagnostic quality was higher than EID diagnostic quality (P = .016, P = .016, and P = .013 for readers 1, 2, and 3, respectively), with significantly better NPS and image quality scores for lung, soft tissue, and bone and with fewer beam-hardening artifacts (all P < .001). Image noise was significantly lower for PCD images in all BMI groups (P < .001 for groups 1 and 3, P < .01 for group 2), with higher CNR for lung nodule detection (12.1 ± 1.7 vs 10.0 ± 1.8, P < .001). Inter- and intrareader reproducibility were good (all ICC > 0.800). Conclusion Initial human experience with dose-reduced PCD chest CT demonstrated lower image noise compared with conventional EID CT, with better diagnostic quality and lung nodule CNR. RSNA, 2017 Online supplemental material is available for this article.
目的 研究在体情况下，与传统能量积分探测器（EID）技术相比，光子计数探测器（PCD）技术是否能改善胸部低剂量计算机断层扫描（CT）的图像质量。材料与方法 本研究经符合健康保险流通与责任法案（HIPAA）的机构审查委员会批准，并获得患者的知情同意。按照CT肺癌筛查的制造商推荐指南（管电压120 kVp，两种探测器的参考管电流-时间乘积均为20 mAs），对30名无症状志愿者进行了低剂量螺旋非增强肺部EID和PCD CT检查。图像的定量分析包括平均衰减、噪声功率谱（NPS）以及肺结节对比噪声比（CNR）的测量。由3名对探测器类型不知情的放射科医生对图像进行定性分析。使用组内相关系数（ICC）评估可重复性。采用McNemar检验、配对t检验和Wilcoxon符号秩检验来比较图像质量。结果 对30名研究对象进行了评估（平均年龄55.0岁±8.7[标准差]；14名男性）。这些患者中，10人体重指数（BMI）正常（BMI范围18.5 - 24.9 kg/m²；第1组），10人超重（BMI范围25.0 - 29.9 kg/m²；第2组），10人肥胖（BMI≥30.0 kg/m²，第3组）。PCD的诊断质量高于EID（读者1、2、3的P值分别为0.016、0.016和0.013），其肺部、软组织和骨骼的NPS及图像质量评分显著更好，硬化伪影更少（所有P < 0.001）。所有BMI组中，PCD图像的噪声均显著更低（第1组和第3组P < 0.001，第2组P < 0.01），肺结节检测的CNR更高（12.1±1.7对10.0±1.8，P < 0.001）。读者间和读者内的可重复性良好（所有ICC > 0.800）。结论 低剂量PCD胸部CT的初步人体试验表明，与传统EID CT相比，其图像噪声更低，诊断质量和肺结节CNR更好。RSNA，2017 本文有在线补充材料。
