Huflage Henner, Hendel Robin, Kunz Andreas Steven, Ergün Süleyman, Afat Saif, Petri Nils, Hartung Viktor, Gruschwitz Philipp, Bley Thorsten Alexander, Grunz Jan-Peter
From the Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Würzburg, Germany (H.H., R.H., A.S., V.H., P.G., T.A., J.-P.G.); Institute of Anatomy and Cell Biology, University of Würzburg, Würzburg, Germany (S.E.); Department of Diagnostic and Interventional Radiology, University Hospital Tübingen, Tübingen, Germany (S.A.); and Department of Internal Medicine I, University Hospital Würzburg, Würzburg, Germany (N.P.).
Invest Radiol. 2024 Apr 1;59(4):293-297. doi: 10.1097/RLI.0000000000001013.
The aim of this study was to investigate potential benefits of ultra-high resolution (UHR) over standard resolution scan mode in ultra-low dose photon-counting detector CT (PCD-CT) of the lung.
Six cadaveric specimens were examined with 5 dose settings using tin prefiltration, each in UHR (120 × 0.2 mm) and standard mode (144 × 0.4 mm), on a first-generation PCD-CT scanner. Image quality was evaluated quantitatively by noise comparisons in the trachea and both main bronchi. In addition, 16 readers (14 radiologists and 2 internal medicine physicians) independently completed a browser-based pairwise forced-choice comparison task for assessment of subjective image quality. The Kendall rank coefficient ( W ) was calculated to assess interrater agreement, and Pearson's correlation coefficient ( r ) was used to analyze the relationship between noise measurements and image quality rankings.
Across all dose levels, image noise in UHR mode was lower than in standard mode for scan protocols matched by CTDI vol ( P < 0.001). UHR examinations exhibited noise levels comparable to the next higher dose setting in standard mode ( P ≥ 0.275). Subjective ranking of protocols based on 5760 pairwise tests showed high interrater agreement ( W = 0.99; P ≤ 0.001) with UHR images being preferred by readers in the majority of comparisons. Irrespective of scan mode, a substantial indirect correlation was observed between image noise and subjective image quality ranking ( r = -0.97; P ≤ 0.001).
In PCD-CT of the lung, UHR scan mode reduces image noise considerably over standard resolution acquisition. Originating from the smaller detector element size in fan direction, the small pixel effect allows for superior image quality in ultra-low dose examinations with considerable potential for radiation dose reduction.
本研究旨在探讨在肺部超低剂量光子计数探测器CT（PCD-CT）中，超高分辨率（UHR）相对于标准分辨率扫描模式的潜在优势。
使用第一代PCD-CT扫描仪，对六个尸体标本采用五种剂量设置进行检查，每种设置均采用锡预滤波，分别在UHR（120×0.2mm）和标准模式（144×0.4mm）下进行。通过气管和双侧主支气管的噪声比较对图像质量进行定量评估。此外，16名阅片者（14名放射科医生和2名内科医生）独立完成基于浏览器的成对强制选择比较任务，以评估主观图像质量。计算肯德尔等级系数（W）以评估阅片者间的一致性，并使用皮尔逊相关系数（r）分析噪声测量与图像质量排名之间的关系。
在所有剂量水平下，对于CTDIvol匹配的扫描方案，UHR模式下的图像噪声低于标准模式（P<0.001）。UHR检查的噪声水平与标准模式下的下一个更高剂量设置相当（P≥0.275）。基于5760次成对测试的方案主观排名显示阅片者间具有高度一致性（W = 0.99；P≤0.001），在大多数比较中，阅片者更喜欢UHR图像。无论扫描模式如何，图像噪声与主观图像质量排名之间均存在显著的间接相关性（r = -0.97；P≤0.001）。
在肺部PCD-CT中，UHR扫描模式比标准分辨率采集显著降低了图像噪声。由于扇形方向上探测器元件尺寸较小产生的小像素效应，在超低剂量检查中可实现卓越的图像质量，并具有大幅降低辐射剂量的潜力。
