Wessling Johannes, Fischbach Roman, Meier Norbert, Allkemper Thomas, Klusmeier Jutta, Ludwig Karl, Heindel Walter
Department of Clinical Radiology, University of Muenster, Albert-Schweitzer-Strasse 33, 48 149 Muenster, Germany.
Radiology. 2003 Sep;228(3):753-9. doi: 10.1148/radiol.2283020928.
To determine optimal detector collimation, section thickness, and tube current for multi-detector row computed tomography (CT) colonography.
An anthropomorphic colon phantom with simulated polyps of varying size (2, 6, 8, 10, and 12 mm) was examined by using multi-detector row CT with varying combinations of detector collimation (4 x 1.0 mm and 4 x 2.5 mm), dose per section (10, 20, 40, 60, 80, 100, and 140 mAs), and section thickness/reconstruction interval (1.25/0.6, 2.0/1.0, 3.0/1.0, and 5.0/2.0 mm). Polyp depiction, longitudinal polyp distortion, and presence of rippling artifacts were assessed on reformatted three-dimensional endoluminal images by three reviewers.
Longitudinal distortion and rippling artifacts increased with increasing section thickness and use of broader detector collimation. Polyps 8 mm or larger were depicted with any combination of section thickness, detector collimation, and tube current. Depiction of polyps 6 mm or smaller depended on the detector collimation/reconstructed section thickness and was rated optimal for the 4 x 1.0-mm detector collimation with a section thickness of 1.25 mm. This was also observed for low-dose protocols. Polyps 6 mm or smaller that were not detected with 3-mm section thickness and 4 x 2.5-mm detector collimation were detected with 1.25-mm section thickness and 10 mAs.
A narrow detector collimation with thin-section imaging (4 x 1.0-mm detector collimation, 1.25-mm section thickness) is a prerequisite for low-dose (10-mAs) multi-detector row CT colonography.
确定多排探测器计算机断层扫描（CT）结肠成像的最佳探测器准直、层厚和管电流。
使用多排探测器CT对带有不同大小（2、6、8、10和12毫米）模拟息肉的仿真人体结肠模型进行检查，采用不同的探测器准直（4×1.0毫米和4×2.5毫米）、每层面剂量（10、20、40、60、80、100和140毫安秒）以及层厚/重建间隔（1.25/0.6、2.0/1.0、3.0/1.0和5.0/2.0毫米）的组合。由三位观察者在重建的三维腔内图像上评估息肉的显示情况、息肉的纵向变形以及波纹状伪影的存在。
纵向变形和波纹状伪影随着层厚增加和使用更宽的探测器准直而增加。8毫米或更大的息肉可通过任何层厚、探测器准直和管电流的组合显示出来。6毫米或更小的息肉的显示取决于探测器准直/重建层厚，对于4×1.0毫米探测器准直和1.25毫米层厚被评为最佳。在低剂量方案中也观察到了这一点。3毫米层厚和4×2.5毫米探测器准直未检测到的6毫米或更小的息肉，在1.25毫米层厚和10毫安秒时被检测到。
窄探测器准直与薄层成像（4×1.0毫米探测器准直，1.25毫米层厚）是低剂量（10毫安秒）多排探测器CT结肠成像的前提条件。
