Swiss Center for Musculoskeletal Imaging, Balgrist Campus AG, Lengghalde 5, Zurich 8008, Switzerland.
Department of Radiology, Balgrist University Hospital, University of Zurich, Zurich, Switzerland.
AJR Am J Roentgenol. 2024 Jan;222(1):e2329950. doi: 10.2214/AJR.23.29950. Epub 2023 Aug 30.
Photon-counting detector (PCD) CT could be useful to help address the typically high radiation doses of conventional energy-integrating detector (EID) CT of the lumbar spine. The purpose of our study was to compare PCD CT and EID CT of the lumbar spine, both performed using tin filtration, in terms of radiation dose and image quality. This study included a prospective sample of 39 patients (22 men, 17 women; mean age, 27.2 years) who underwent investigational PCD CT of the lumbar spine as part of a separate study and a retrospective sample of 39 patients (22 men, 17 women; mean age, 34.9 years) who underwent clinically indicated EID CT of the lumbar spine. In both groups, all examinations were performed using unenhanced technique with tin prefiltration between June 2022 and January 2023. Patients were matched between groups using age, sex, and BMI. A custom gaussian curve-fitting algorithm was used to automatically calculate image noise, SNR, and CNR for each examination, on the basis of all voxels within the image set. Three radiologists independently reviewed examinations to perform a subjective visual assessment of visualization of trabecular architecture, cortical bone, neuroforaminal content, paraspinal muscles, and intervertebral disk, as well as overall image quality, using a 4-point Likert scale (1 = poor, 4 = excellent). PCD CT and EID CT examinations were compared. Mean CTDI was 4.4 ± 1.0 (SD) mGy for PCD CT versus 11.1 ± 1.9 mGy for EID CT ( < .001). Mean size-specific dose estimate (SSDE) was 6.2 ± 1.0 (SD) mGy for PCD CT versus 14.2 ± 1.8 mGy for EID CT ( < .001). PCD CT and EID CT examinations were not significantly different in terms of image noise or SNR (both > .05). PCD CT, in comparison with EID CT, showed significantly higher CNR (mean ± SD, 33.6 ± 3.3 vs 29.3 ± 4.1; < .001). For all three readers, the median score for overall image quality was 4 (range, 3-4) for both PCD CT and EID CT. PCD CT and EID CT examinations showed no significant difference in terms of any qualitative measure for any reader (all > .05). PCD CT, in comparison with EID CT, yielded significantly lower radiation dose with preserved image quality. The findings support expanded use of PCD CT for lumbar spine evaluation.
光子计数探测器（PCD）CT 有助于解决传统能量积分探测器（EID）CT 腰椎扫描通常存在的高辐射剂量问题。本研究旨在比较使用锡预过滤的 PCD CT 和 EID CT 在腰椎扫描中的辐射剂量和图像质量。这项研究包括了一个前瞻性样本，共 39 名患者（22 名男性，17 名女性；平均年龄 27.2 岁），他们在另一项研究中接受了腰椎 PCD CT 检查，以及一个回顾性样本，共 39 名患者（22 名男性，17 名女性；平均年龄 34.9 岁），他们接受了临床推荐的腰椎 EID CT 检查。在这两个组中，所有检查均使用未增强技术，于 2022 年 6 月至 2023 年 1 月之间进行锡预过滤。使用年龄、性别和 BMI 对两组患者进行匹配。使用自定义高斯曲线拟合算法，基于图像集中的所有体素，自动计算每个检查的图像噪声、SNR 和 CNR。三名放射科医生独立对检查结果进行评估，使用 4 分 Likert 量表（1 = 差，4 = 优）对骨小梁结构、皮质骨、神经孔内容物、椎旁肌肉和椎间盘的可视化以及整体图像质量进行主观视觉评估。PCD CT 和 EID CT 检查结果进行了比较。PCD CT 的 CTDI 平均值为 4.4±1.0（SD）mGy，EID CT 为 11.1±1.9 mGy（ <.001）。PCD CT 的 SSDE 平均值为 6.2±1.0（SD）mGy，EID CT 为 14.2±1.8 mGy（ <.001）。PCD CT 和 EID CT 在图像噪声或 SNR 方面无显著差异（均 >.05）。与 EID CT 相比，PCD CT 的 CNR 显著更高（平均±SD，33.6±3.3 比 29.3±4.1； <.001）。对于所有三位读者，PCD CT 和 EID CT 的总体图像质量中位数评分均为 4（范围为 3-4）。对于所有三位读者，PCD CT 和 EID CT 在任何定性指标上均无显著差异（均 >.05）。与 EID CT 相比，PCD CT 可显著降低辐射剂量，同时保持图像质量。这些发现支持在腰椎评估中更广泛地使用 PCD CT。
