1 Division of Radiology, Department of Imaging and Medical Information Sciences, Geneva University Hospitals , Geneva , Switzerland.
Br J Radiol. 2018 Jul;91(1088):20170443. doi: 10.1259/bjr.20170443. Epub 2018 Jun 14.
To compare radiation dose and image quality of thoracoabdominal scans obtained with a high-pitch protocol (pitch 3.2) and iterative reconstruction (Sinogram Affirmed Iterative Reconstruction) in comparison to standard pitch reconstructed with filtered back projection (FBP) using dual source CT.
114 CT scans (Somatom Definition Flash, Siemens Healthineers, Erlangen, Germany), 39 thoracic scans, 54 thoracoabdominal scans and 21 abdominal scans were performed. Analysis of three protocols was undertaken; pitch of 1 reconstructed with FBP, pitch of 3.2 reconstructed with SAFIRE, pitch of 3.2 with stellar detectors reconstructed with SAFIRE. Objective and subjective image analysis were performed. Dose differences of the protocols used were compared.
Dose was reduced when comparing scans with a pitch of 1 reconstructed with FBP to high-pitch scans with a pitch of 3.2 reconstructed with SAFIRE with a reduction of volume CT dose index of 75% for thoracic scans, 64% for thoracoabdominal scans and 67% for abdominal scans. There was a further reduction after the implementation of stellar detectors reflected in a reduction of 36% of the dose-length product for thoracic scans. This was not at the detriment of image quality, contrast-to-noise ratio, signal-to-noise ratio and the qualitative image analysis revealed a superior image quality in the high-pitch protocols.
The combination of a high pitch protocol with iterative reconstruction allows significant dose reduction in routine chest and abdominal scans whilst maintaining or improving diagnostic image quality, with a further reduction in thoracic scans with stellar detectors. Advances in knowledge: High pitch imaging with iterative reconstruction is a tool that can be used to reduce dose without sacrificing image quality.
比较高螺距（3.2 螺距）和迭代重建（正弦图确认迭代重建）与使用双源 CT 的滤波反投影（FBP）重建标准螺距的胸腹部扫描的辐射剂量和图像质量。
共进行了 114 次 CT 扫描（Somatom Definition Flash，西门子医疗，德国埃朗根），其中 39 次为胸部扫描，54 次为胸腹联合扫描，21 次为腹部扫描。对三种方案进行了分析；螺距为 1 时采用 FBP 重建，螺距为 3.2 时采用 SAFIRE 重建，螺距为 3.2 时采用星状探测器采用 SAFIRE 重建。进行了客观和主观的图像分析。比较了所使用方案的剂量差异。
与螺距为 1 的 FBP 重建扫描相比，螺距为 3.2 的 SAFIRE 重建扫描的剂量降低，胸部扫描的容积 CT 剂量指数降低 75%，胸腹联合扫描降低 64%，腹部扫描降低 67%。在实施星状探测器后进一步降低剂量，反映在胸部扫描的剂量长度乘积降低 36%。这并没有影响图像质量，对比度噪声比、信噪比和定性图像分析显示高螺距方案具有更高的图像质量。
高螺距方案与迭代重建相结合，可在常规胸部和腹部扫描中显著降低剂量，同时保持或提高诊断图像质量，而使用星状探测器进一步降低胸部扫描剂量。
高螺距成像与迭代重建相结合是一种可以降低剂量而不牺牲图像质量的工具。
