From the Clinic of Radiology and Nuclear Medicine (M.T., C.R., D.H., J.L., U.S., S.S., A.H.), University of Basel Hospital, Basel, Switzerland
From the Clinic of Radiology and Nuclear Medicine (M.T., C.R., D.H., J.L., U.S., S.S., A.H.), University of Basel Hospital, Basel, Switzerland.
AJNR Am J Neuroradiol. 2018 Feb;39(2):385-391. doi: 10.3174/ajnr.A5490. Epub 2017 Dec 21.
While the use of cervical spine CT in trauma settings has increased, the balance between image quality and dose reduction remains a concern. The purpose of our study was to compare the image quality of CT of the cervical spine of cadaveric specimens at different radiation dose levels.
The cervical spine of 4 human cadavers (mean body mass index; 30.5 ± 5.2 kg/m; range, 24-36 kg/m) was examined using different reference tube current-time products (45, 75, 105, 135, 150, 165, 195, 275, 355 mAs) and a tube voltage of 120 kV(peak). Data were reconstructed with filtered back-projection and iterative reconstruction. Qualitative image noise and morphologic characteristics of bony structures were quantified on a Likert scale. Quantitative image noise was measured. Statistics included analysis of variance and the Tukey test.
Compared with filtered back-projection, iterative reconstruction provided significantly lower qualitative (mean noise score: iterative reconstruction = 2.10/filtered back-projection = 2.18; = .003) and quantitative (mean SD of Hounsfield units in air: iterative reconstruction = 30.2/filtered back-projection = 51.8; < .001) image noise. Image noise increased as the radiation dose decreased. Qualitative image noise at levels C1-4 was rated as either "no noise" or as "acceptable noise." Any shoulder position was at level C5 and caused more artifacts at lower levels. When we analyzed all spinal levels, scores for morphologic characteristics revealed no significant differences between 105 and 355 mAs ( = .555), but they were worse in scans at 75 mAs ( = .025).
Clinically acceptable image quality of cervical spine CTs for evaluation of bony structures of cadaveric specimens with different body habitus can be achieved with a reference mAs of 105 at 120 kVp with iterative reconstruction. Pull-down of shoulders during acquisition could improve image quality but may not be feasible in trauma patients with unknown injuries.
虽然在创伤环境中使用颈椎 CT 有所增加，但仍需关注图像质量和剂量减少之间的平衡。本研究的目的是比较不同辐射剂量水平下颈椎 CT 对尸体标本的图像质量。
对 4 具人体尸体（平均体质指数为 30.5 ± 5.2kg/m，范围为 24-36kg/m）的颈椎进行检查，采用不同的参考管电流-时间产品（45、75、105、135、150、165、195、275、355mAs）和 120kV（峰值）管电压。数据采用滤波反投影和迭代重建进行重建。通过李克特量表对骨结构的形态特征和图像噪声进行定量评估。测量图像噪声的定量值。统计分析包括方差分析和 Tukey 检验。
与滤波反投影相比，迭代重建提供了明显较低的定性（平均噪声评分：迭代重建 = 2.10/滤波反投影 = 2.18； =.003）和定量（空气中单位的平均 SD 的 Hounsfield 单位：迭代重建 = 30.2/滤波反投影 = 51.8； <.001）图像噪声。随着辐射剂量的降低，图像噪声增加。C1-4 水平的定性图像噪声被评为“无噪声”或“可接受噪声”。任何肩部位置都在 C5 水平，并且在较低水平下会导致更多的伪影。当我们分析所有脊柱水平时，形态特征的评分显示 105 和 355mAs 之间没有显著差异（ =.555），但在 75mAs 时则更差（ =.025）。
对于不同体型尸体标本的骨骼结构评估，可以使用 120kVp 时的 105mAs 参考 mAs 和迭代重建来实现具有临床可接受的颈椎 CT 图像质量。在采集过程中下拉肩部可以改善图像质量，但在未知受伤的创伤患者中可能不可行。
