董海鹏 1林晓珠 1缪飞 1张帅 2沈云 2陈克敏1
作者信息
- 1. 上海交通大学医学院附属瑞金医院放射科,上海200025
- 2. 通用电器中国CT影像研究室,北京100176
- 折叠
摘要
Abstract
Objective To select the optimal monochromatic energy level for CT spectral imaging of brain via considering the reduction of image noise and beam hardening artifacts (BHAs). Methods Eighty patients scanned with GSI mode on Discovery CT750HD were enrolled. Six sets of CT images were obtained from a single GSI acquisition: conventional 140 kVp polychromatic images and 5 sets of monochromatic images (80 keV, 75 keV, 70 keV, 65 keV and 60 keV). The background noise in corona and BHAs in 4 anatomic regions (medulla oblongata, cerebellar, pons and inferior part of frontal lobe) were measured and compared. BHA was defined as the square root of the noise difference between the region of interest (ROI) and background. Results Compared with polychromatic image, 70keV and 65keV images had lower background noise (P<0.001), while 80 keV, 75 keV, and 60 keV images had higher background noise (P<0.001). The reductions of background noise of 70 keV and 65 keV were (10.8±4.1)% and (10.0±7.6)%, respectively, and there was no difference in background noise between 70 keV and 65 keV (P=0.252). The BHAs of 70 keV and 65 keV sets were lower than that of conventional 140 kVp polychromatic image set (P<0.05), and the average BHAs value of 70 keV image set was lower than that of 65 keV (P<0.05). The reductions of BHAs of 70 keV and 65 keV image sets for the 4 anatomic regions were 24.2%, 55.9%, 27.6%, 20.9% and 3.2%, 41.6%, 5.7%, 17.4%, respectively. Conclusions For spectral CT of brain, the optimal monochromatic energy level was 70 keV, which provided optimal reduction of both image noise (10.8%) and beam hardening artifacts when compared with that of conventional polychromatic images.关键词
颅脑/X线计算机断层扫描/能谱成像/图像噪声/线束硬化伪影Key words
Brain/X-ray computed tomography/Spectral imaging/Image noise/Beam-hardening artifacts分类
医药卫生
