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 postprocessing 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.