Boiselle Phillip M, Dippolito Giuseppe, Copeland John, Kang Haejin, Ahmed Muneeb, Weeks Dawn, Halpern Elkan, Goldberg S Nahum
Department of Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Ave, Boston, MA 02215, USA.
Radiology. 2003 Jul;228(1):107-11. doi: 10.1148/radiol.2281020730.
To compare in an animal model the image quality of multiplanar reformation and three-dimensional (3D) reconstruction images of the central airways by using single-detector row computed tomography (CT) and multi-detector row CT at varied tube currents and to compare radiation dose.
Five dogs each underwent five consecutive helical CT examinations (one single-detector row CT examination at 240 mA and four multi-detector row CT examinations at 240, 120, 40, and 20 mA), with 0.8-second gantry rotation time. Multiplanar reformation and 3D reconstruction images were created from each of the 25 CT acquisitions. The images were randomized and blindly reviewed with consensus agreement by three radiologists who graded image quality by using a five-point scale. In a separate review, the three radiologists independently used a four-point scale to rank the comparative image quality of the multi-detector row CT 3D images, while blinded to specific tube currents. The radiation doses were measured for each type of scan, and the relative radiation dose length products that were normalized to single-detector row CT values were used to compare radiation doses of the various CT techniques. Statistical analysis was performed with the Wilcoxon signed-rank test and the Friedman analysis of variance test.
Image quality was consistently ranked higher for multi-detector row CT images than for single-detector row CT images (P =.03). Although there were no distinguishable differences between images obtained with multi-detector row CT at 240, 120, or 40 mA, images obtained with 20 mA were given a significantly (P =.04) lower relative rank (mean, 2.4) than those obtained with higher tube currents (mean, 1.4-1.7). Multi-detector row CT radiation doses were 1.64, 0.82, 0.27, and 0.14 (for 240-, 120-, 40-, and 20-mA multi-detector row CT, respectively) relative to the dose for 240-mA single-detector row CT.
Multi-detector row CT is superior to single-detector row CT for multiplanar and 3D imaging of the central airways. Substantial dose reductions can be made, while maintaining high image quality.
在动物模型中，比较使用单排探测器计算机断层扫描（CT）和多排探测器CT在不同管电流下对中央气道进行多平面重建和三维（3D）重建图像的图像质量，并比较辐射剂量。
5只狗每只连续接受5次螺旋CT检查（1次240 mA的单排探测器CT检查和4次240、120、40和20 mA的多排探测器CT检查），机架旋转时间为0.8秒。从25次CT采集的每一次中创建多平面重建和3D重建图像。图像随机排列，由三位放射科医生进行盲法评估并达成共识，他们使用五点量表对图像质量进行分级。在另一次评估中，三位放射科医生在不知道具体管电流的情况下，独立使用四点量表对多排探测器CT 3D图像的比较图像质量进行排名。测量每种扫描类型的辐射剂量，并使用相对于单排探测器CT值进行归一化的相对辐射剂量长度乘积来比较各种CT技术的辐射剂量。采用Wilcoxon符号秩检验和Friedman方差分析进行统计分析。
多排探测器CT图像的质量始终高于单排探测器CT图像（P = 0.03）。虽然在240、120或40 mA下使用多排探测器CT获得的图像之间没有明显差异，但20 mA下获得的图像的相对排名（平均为2.4）明显低于较高管电流下获得的图像（平均为1.4 - 1.7）（P = 0.04）。相对于240 mA单排探测器CT的剂量，多排探测器CT的辐射剂量分别为1.64、0.82、0.27和0.14（分别对应240、120、40和20 mA的多排探测器CT）。
在中央气道的多平面和3D成像方面，多排探测器CT优于单排探测器CT。在保持高图像质量的同时，可以大幅降低剂量。
