摘要
目的：评价能谱CT结肠成像提高小于10 mm结肠息肉检出率的有效性,并找到显示结肠息肉最佳的单能量图像.材料和方法：两段离体猪结肠通过结扎黏膜法分别获得连续的模拟息肉,第一段结肠内含有直径1 ～5 mm息肉20枚,第二段结肠含有1～10 mm息肉20枚.第一段结肠使用64排单源宝石能谱CT在40～140 keV范围内扫描,提取45、60、75、90、105、120和135 keV单能量图像数据,再使用普通64排多螺旋CT图像在同等条件扫描作为对照；第二段使用64排单源能谱CT结肠在三种固定辐射剂量（17.77 mGy、25.53 mGy和32.52 mGy）下分别进行45、60、75、90、105、120和135 keV单能量能谱CT扫描；各组图像经后处理获得CT仿真内窥镜、多平面重建和虚拟分割图像.对每组图像进行主观及客观评价,记录并比较每组图像.中的息肉检出率以及平均对比噪声比.结果：结肠息肉离体模型研究显示应用单能量能谱CT对结肠息肉检出率略高于常规64排螺旋CT（P＞0.05）;75 keV单能量图像显示结肠息肉的对比噪声比最高（P＜0.05）.结论：能谱CT结肠成像可轻度提高小结肠息肉（≤5 mm）的检出率,显示结肠息肉的最佳单能谱图像为75 keV图像.
Objective： To evaluate the efficacy of CT colonography with spectral imaging in detecting small phantom colonic polyps and find the best single spectral images. Materials and Methods： Two segments of twenty artificial polyps sized from 1 mm to 10 mm （ten sized smaller than 5 mm and ten sized over 5 ram） were established by ligation in a segment of porcine colon. The phantom colon were inflated and immerged into 0.1% iodine solution. Volume data were acquired on a 64-muhi detector gemstone CT scanner single spectral images at 45, 60, 75, 90, 105, 120 and 135 keV were reconstructed. CT virtual endoscopy（CTVE）, muhiplanar reformation（MPR） and virtual dissection（VD） models were reconstructed. Two radiolo- gists blinded to the polyps location assessed every image setting. Contrast to noise ratios （CNR） as well as detecting rates of the polyps were calculated and compared statistically among different acquisitions. Results： The phantom study revealed that the detecting rates of colonic polyps were higher than conventional for those polyps less than 5 mm（P〉0.05）. The bset CNR is in 75 keV＇s single spectral image. Conclusion： Spectral CT colonography is efficient in detecting small colonic polyps, the best single spectral images is 75 keV.
出处
《中国临床医学影像杂志》
CAS
2012年第1期13-16,共4页
Journal of China Clinic Medical Imaging
