The Value of Multi-Slice CT Automatic tube-current Modulation Technique Combine Multiple Quantum Denoising Techniques of Liver Multi-phases Contrast Enhanced Scanning

目的：评价肝脏MSCT多期增强扫描采用自动管电流调制技术并应用多种量子降噪技术(Q01、Q02、USO)降低图像噪声、提高图像质量的价值。方法连续58例行肝脏MSCT平扫和增强扫描的患者纳入本研究。使用Toshiba Aquilion 16层CT，管电压120kVp、机架旋转0.5秒/圈、螺距0.938、准直层厚1mm*16层、图像重建层厚7mm，采用自动管电流调制技术，目标噪声为10.0HU，CT机根据定位像扫描时获取的信息设置扫描时的管电流，范围100-400mA。标准软组织算法分别在不使用、使用Q01、Q02和USO降噪技术时重建层厚为1、3、5、7、10mm的图像共20组。测量肝门层面肝右叶、腹主动脉、脾脏和前腹壁皮下脂肪的图像噪声并计算平均值。根据图像噪声、病变显示、诊断可接受度将图像质量分3级，1mm图像增加三维后处理图像比较，由CT副主任技师和副主任医师各1名进行双盲法评价。结果图像噪声随着层厚的变薄而增加，使用Q01、Q02、USO可不同程度的降低噪声，提高图像质量，层厚越薄噪声越大时降噪幅度越大。使用Q01、Q02和USO可使噪声分别下降3.1-5.8HU、4.5-8.3HU和5.5-12.6HU。层厚10mm不使用QD、7mm使用Q01、5mm和3mm使用Q02、层厚1mm使用USO可获得最佳的图像质量。结论肝脏MSCT增强扫描采用自动管电流调制技术并根据层厚选择不同的量子降噪技术即可降低图像噪声又能提高图像质量。Objective Retrospectively evaluate the value of liver multi-phases contrast enhanced scanning with Multi-Slice CT automatic tube-current modulation(ATCM) technique combine various quantum denoising techniques (Q01, Q02, USO) to decrease image noise and improve image quality.Methods Consecutive 58 patients performed liver multi-phases contrast enhanced scanning were enrolled this study. Toshiba Aquilion 16-slices CT, Tube Voltage 120kVp, gantry rotation time 0.5s/r, pitch 0.938, detector collimation thickness 1mm×16, image reconstruction thickness 7mm. The target image noise level of ATCM was 10HU and the machine automatically set the tube-current in scanning according to attenuated information of liver in scanogram, the dynamic range of tube-current was 100 to 400mA. Reconstructed total 20 groups images of 1, 3, 5, 7, 10mm images using standard soft tissue algorithm with no filter, Q01, Q02 and USO respectively. Measured image noise of right liver lobe at liver hilar plane, abdomenal aorta, spleen and subcutaneous fat of front belly wall and calculated average value. Images were divided into 3 scales(excellent, good, poor) by one CT technologist and one radiologist with double blind method on the basis of image noise, lesion display, diagnostic acceptability. 1mm images were compared with additional three dimension post-processing images of VR, MPR, MIP and CPR.Results Image noise increased along with image thickness got thinner, using Q01, Q02 and USO decreased image noise in varying degrees and improved image quality, the thinner thickness,the higher image noise and the more degrees of noise decreasing. Image noise decreased 3.1-5.8HU, 4.5-8.3HU and 5.5-12.6HU by using Q01, Q02 and USO respectively. The best image quality acquired in 10mm image thickness without QD, 7mm with Q01, 5mm and 3mm with Q02, 1mm with USO.Conclusion Liver multi-phases contrast enhanced scanning with Multi-Slice CT automatic tube-current modulation technique combine various quantum denoising techniques (Q01, Q02, USO) according to image thickness can decrease image noise and improve image quality.深圳市科技研发资金项目; 深圳市医疗卫生科研项目771-731