Department of Radiology, Neuroradiology and Nuclear Medicine, Johannes Wesling University Hospital, Ruhr University Bochum, Bochum, Germany.
Johannes Wesling University Hospital By Muehlenkreiskliniken AöR, Hans-Nolte-Straße 1, 32429, Minden, Germany.
Neuroradiology. 2024 May;66(5):729-736. doi: 10.1007/s00234-024-03308-z. Epub 2024 Feb 27.
To determine the optimal virtual monoenergetic image (VMI) for detecting and assessing intracranial hemorrhage in unenhanced photon counting CT of the head based on the evaluation of quantitative and qualitative image quality parameters.
Sixty-three patients with acute intracranial hemorrhage and unenhanced CT of the head were retrospectively included. In these patients, 35 intraparenchymal, 39 intraventricular, 30 subarachnoidal, and 43 subdural hemorrhages were selected. VMIs were reconstructed using all available monoenergetic reconstruction levels (40-190 keV). Multiple regions of interest measurements were used for evaluation of the overall image quality, and signal, noise, signal-to-noise-ratio (SNR), and contrast-to-noise-ratio (CNR) of intracranial hemorrhage. Based on the results of the quantitative analysis, specific VMIs were rated by five radiologists on a 5-point Likert scale.
Signal, noise, SNR, and CNR differed significantly between different VMIs (p < 0.001). Maximum CNR for intracranial hemorrhage was reached in VMI with keV levels > 120 keV (intraparenchymal 143 keV, intraventricular 164 keV, subarachnoidal 124 keV, and subdural hemorrhage 133 keV). In reading, no relevant superiority in the detection of hemorrhage could be demonstrated using VMIs above 66 keV.
For the detection of hemorrhage in unenhanced CT of the head, the quantitative analysis of the present study on photon counting CT is generally consistent with the findings from dual-energy CT, suggesting keV levels just above 120 keV and higher depending on the location of the hemorrhage. However, on the basis of the qualitative analyses, no reliable statement can yet be made as to whether an additional VMI with higher keV is truly beneficial in everyday clinical practice.
基于对定量和定性图像质量参数的评估，确定用于检测和评估头部未增强光子计数 CT 中颅内出血的最佳虚拟单能量图像 (VMI)。
回顾性纳入 63 例急性颅内出血和头部未增强 CT 的患者。在这些患者中，选择了 35 例脑实质内、39 例脑室内、30 例蛛网膜下腔和 43 例硬膜下出血。使用所有可用的单能量重建水平（40-190keV）重建 VMI。使用多个感兴趣区域测量来评估整体图像质量以及颅内出血的信号、噪声、信噪比 (SNR) 和对比噪声比 (CNR)。根据定量分析的结果，五位放射科医生对特定的 VMI 进行了 5 分制的评分。
不同 VMI 之间的信号、噪声、SNR 和 CNR 差异有统计学意义（p<0.001）。颅内出血的最大 CNR 在 keV 水平>120keV 的 VMI 中达到（脑实质内 143keV，脑室内 164keV，蛛网膜下腔 124keV，硬膜下出血 133keV）。在阅读过程中，无法证明使用 66keV 以上的 VMI 对出血的检测具有相关性。
对于头部未增强 CT 中的出血检测，本研究对光子计数 CT 的定量分析通常与双能 CT 的发现一致，表明根据出血位置，keV 水平略高于 120keV 或更高。然而，基于定性分析，目前尚无法确定更高 keV 的附加 VMI 是否在日常临床实践中真正有益。
