Frellesen Claudia, Wichmann Julian L, Tischendorf Patricia, Scholtz Jan-Erik, Beeres Martin, Vogl Thomas J, Bauer Ralf W
1 Department of Diagnostic and Interventional Radiology, Clinic of the Goethe University Frankfurt, Frankfurt am Main, Germany.
2 RNS, Private Radiology and Radiation Therapy Group, Wiesbaden, Germany.
Acta Radiol. 2018 Aug;59(8):909-916. doi: 10.1177/0284185117740931. Epub 2017 Nov 6.
Background Image quality benefits from high-pitch scanning in agitated patients by reducing acquisition time. Purpose To compare image quality and exposure parameters in patients with maxillofacial trauma on second- and third-generation dual-source computed tomography (DSCT). Material and Methods Four groups were compared. Group 1 was examined on second-generation DSCT (120 kV/50 mAs, pitch 3.0). The other three groups were examined on third-generation DSCT. Group 2 was scanned with 120 kV/50 mAs, pitch 2.2. Automated exposure control (AEC) was used in group 3 and group 4 with pitch factors of 2.2 and 3.0, respectively. Images of third-generation DSCT were reconstructed with iterative reconstruction (IR), of second-generation DSCT with filtered back-projection. CTDIvol, acquisition time, and image quality were compared. Results Thirty patients were included in each group. Average CTDIvol (2.76 ± 0.00 mGy, 2.66 ± 0.00 mGy, 0.74 ± 0.23 mGy, and 0.75 ± 0.17 mGy) was significantly lower on third-generation DSCT with AEC ( P < 0.001). Subjective image quality was rated worst in group 4 due to strong high-pitch artifacts, while in the remaining three groups it was rated good or very good with good inter-observer agreement (k > 0.64). Average acquisition time was significantly shorter with third-generation DSCT (0.47 s, 0.36 s, 0.38 s, 0.30 s; P < 0.001). Conclusion Third-generation DSCT yields faster acquisition times and substantial dose reduction with AEC. A pitch of 2.2 should be preferred, as it results in fewer artifacts. If AEC is used, latest IR ensures that diagnostic image quality is guaranteed.
在躁动患者中，高螺距扫描可缩短采集时间，从而提高图像质量。目的：比较第二代和第三代双源计算机断层扫描（DSCT）对颌面部创伤患者的图像质量和曝光参数。材料与方法：比较四组。第一组在第二代DSCT上进行检查（120 kV/50 mAs，螺距3.0）。其他三组在第三代DSCT上进行检查。第二组以120 kV/50 mAs、螺距2.2进行扫描。第三组和第四组分别使用自动曝光控制（AEC），螺距因子分别为2.2和3.0。第三代DSCT图像采用迭代重建（IR），第二代DSCT图像采用滤波反投影重建。比较容积CT剂量指数（CTDIvol）、采集时间和图像质量。结果：每组纳入30例患者。第三代DSCT采用AEC时，平均CTDIvol（2.76±0.00 mGy、2.66±0.00 mGy、0.74±0.23 mGy和0.75±0.17 mGy）显著更低（P<0.001）。第四组主观图像质量因强烈的高螺距伪影被评为最差，而其余三组被评为良好或非常好，观察者间一致性良好（k>0.64）。第三代DSCT的平均采集时间显著更短（0.47 s、0.36 s、0.38 s、0.30 s；P<0.001）。结论：第三代DSCT采用AEC可实现更快的采集时间和大幅剂量降低。应首选螺距2.2，因为其产生的伪影更少。如果使用AEC，最新的IR可确保保证诊断图像质量。
