Shen Hesong, Liang Dan, Luo Mingyue, Duan Chaijie, Cai Wenli, Zhu Shanshan, Qiu Jianping, Li Wenru
Department of Radiology, The Sixth Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, China.
Research Center of Biomedical Engineering, Graduate School at Shenzhen, Tsinghua University, Shenzhen, Guangdong, China.
PLoS One. 2015 Jan 30;10(1):e0117116. doi: 10.1371/journal.pone.0117116. eCollection 2015.
To investigate image quality and radiation dose of CT colonography (CTC) with adaptive iterative dose reduction three-dimensional (AIDR3D).
Ten segments of porcine colon phantom were collected, and 30 pedunculate polyps with diameters ranging from 1 to 15 mm were simulated on each segment. Image data were acquired with tube voltage of 120 kVp, and current doses of 10 mAs, 20 mAs, 30 mAs, 40 mAs, 50 mAs, respectively. CTC images were reconstructed using filtered back projection (FBP) and AIDR3D. Two radiologists blindly evaluated image quality. Quantitative evaluation of image quality included image noise, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR). Qualitative image quality was evaluated with a five-score scale. Radiation dose was calculated based on dose-length product. Ten volunteers were examined supine 50 mAs with FBP and prone 20 mAs with AIDR3D, and image qualities were assessed. Paired t test was performed for statistical analysis.
For 20 mAs with AIDR3D and 50 mAs with FBP, image noise, SNRs and CNRs were (16.4 ± 1.6) HU vs. (16.8 ± 2.6) HU, 1.9 ± 0.2 vs. 1.9 ± 0.4, and 62.3 ± 6.8 vs. 62.0 ± 6.2, respectively; qualitative image quality scores were 4.1 and 4.3, respectively; their differences were all not statistically significant. Compared with 50 mAs with FBP, radiation dose (1.62 mSv) of 20 mAs with AIDR3D was decreased by 60.0%. There was no statistically significant difference in image noise, SNRs, CNRs and qualitative image quality scores between prone 20 mAs with AIDR3D and supine 50 mAs with FBP in 10 volunteers, the former reduced radiation dose by 61.1%.
Image quality of CTC using 20 mAs with AIDR3D could be comparable to standard 50 mAs with FBP, radiation dose of the former reduced by about 60.0% and was only 1.62 mSv.
探讨采用自适应迭代剂量降低三维成像（AIDR3D）的CT结肠成像（CTC）的图像质量和辐射剂量。
收集10段猪结肠模型，每段模拟30个直径为1至15毫米的带蒂息肉。采用管电压120 kVp，电流剂量分别为10 mAs、20 mAs、30 mAs、40 mAs、50 mAs采集图像数据。使用滤波反投影（FBP）和AIDR3D重建CTC图像。两名放射科医生对图像质量进行盲法评估。图像质量的定量评估包括图像噪声、信噪比（SNR）和对比噪声比（CNR）。采用五分制对图像质量进行定性评估。根据剂量长度乘积计算辐射剂量。对10名志愿者进行检查，仰卧位采用FBP 50 mAs，俯卧位采用AIDR3D 20 mAs，并评估图像质量。采用配对t检验进行统计分析。
对于AIDR3D 20 mAs和FBP 50 mAs，图像噪声、SNR和CNR分别为（16.4±1.6）HU对（16.8±2.6）HU、1.9±0.2对1.9±0.4、62.3±6.8对62.0±6.2；定性图像质量评分分别为4.1和4.3；差异均无统计学意义。与FBP 50 mAs相比，AIDR3D 20 mAs的辐射剂量（1.62 mSv）降低了60.0%。10名志愿者中，AIDR3D俯卧位20 mAs与FBP仰卧位50 mAs在图像噪声、SNR、CNR和定性图像质量评分方面差异无统计学意义，前者辐射剂量降低了61.1%。
采用AIDR3D 20 mAs的CTC图像质量与标准的FBP 50 mAs相当，前者辐射剂量降低约60.0%，仅为1.62 mSv。
