肝脏CT动态增强扫描非刚性对位减影技术的质量评价

目的利用血管减影前后的吻合程度，探讨非刚性对位减影技术在肝脏CT动态增强检查中的质量评价。 方法收集2018年12月至2019年2月于中山大学附属第一医院行肝脏CT动态增强检查的50例患者资料，使用非刚性对位减影技术获得减影图像，对减影前后的图像质量进行评价，定性评价包括图像伪影情况及解剖错配程度，定量评价测量各血管（腹主动脉、肝右动脉、肝左动脉、门静脉主干、门静脉右支、门静脉左支）减影前后在动脉晚期、门静脉晚期的CT值。采用混合线性效应模型及拟合方程评估减影前后各血管的CT值曲线拟合程度。 结果减影后图像均无明显解剖结构错配导致的伪影，3名测量者一致性较高（ICC=0.844，P<0.001）。减影技术一定程度上会降低各血管的CT值，与强化分期不存在交互作用。无论是在动脉晚期还是门静脉晚期，减影前后各血管CT值走势一致，CT值变化曲线吻合。 结论非刚性对位减影技术可轻松实现肝脏CT动态增强检查的图像减影，并获得良好的图像质量。

Quality evaluation of non-rigid subtraction technique in CT dynamic enhancement scanning of liver

ObjectiveTo evaluate the quality of non-rigid subtraction technique in CT dynamic enhancement scanning of liver. MethodsThe image data of fifty patients undergoing CT dynamic enhancement scanning of liver were retrospectively collected from December 2018 to February 2019 in the First Affiliated Hospital of Sun Yat-sen University. The subtraction images were obtained by non-rigid subtraction technique. The image quality before and after subtraction was evaluated. Qualitative evaluation included image artifacts and anatomical mismatch degree. The CT value of each blood vessel (abdominal aorta, right hepatic artery, left hepatic artery, portal vein trunk, right portal vein branch, and left portal vein branch) before and after the subtraction were measured quantitatively in the arterial and portal vein phases, mixed linear effect model and fitting equation were used to evaluate the fitting degree of CT value curve of each blood vessel before and after subtraction. ResultsThere were no obvious artifacts caused by anatomical mismatch of the images after non-rigid subtraction, and the consistency of three surveyors was high (ICC=0.844,P<0.001). Subtraction technique could reduce the CT value of each blood vessel to a certain extent, and there was no interaction with enhancement phase. The CT values of each blood vessel before and after subtraction showed the same trend in both late arteries and the CT value curve was consistent. ConclusionNon-rigid subtraction technique can be applied to CT dynamic enhancement scanning of liver to obtain high quality images.