宽体探测器CT多物质伪影降低技术在经颈静脉肝内门体分流术及栓塞术后门静脉血管成像中的应用价值

Application of a multi-material artifact reduction algorithm in a wide-detector CT in the evaluation of the portal venous angiography of postoperative TIPS and embolization

目的 通过比较能谱CT门静脉血管成像质量,评价单能量成像及金属伪影削减(MAR)算法对经颈静脉肝内门体分流术(TIPS)及栓塞术后图像质量的影响。 方法 前瞻性收集2017年12月至2018年4月郑州大学第一附属医院介入科及肝胆外科收治的因肝硬化门脉高压行TIPS及栓塞治疗1个月后行门静脉血管成像的28例患者检查资料。采用Revolution CT进行能谱扫描,重建60 kev、120 kev、120 kV-like、60+120 keV融合图像及120 keV+120 kV-like融合图像并经金属伪影消减(MAR)算法处理的图像,计算各组图像的伪影指数(AI),并对各组图像进行主观评分。比较各组间的图像质量。 结果 120 keV图像的AI值最低(30.8±8.5,18.2±4.3),去除伪影效果最明显,60 keV图像的AI值最高(57.3±15.7,32.1±7.9),伪影的影响最明显,60 keV+120 keV融合图像较60 keV图像的AI值降低(26.2%,24.7%),各组图像之间的AI值的差异均有统计学意义(均P<0.05)。两位医师对各组图像主观图像质量评价结果一致性良好,kappa值为0.824。60 keV+120 keV图像的总体图像质量评分及120 kV-like+120 keV图像噪声评分高于其他各组,各组图像之间主观评分的差异均有统计学意义(均P<0.05)。 结论 在单能量成像及MAR处理基础上,60 keV+120 keV融合图像能在消除伪影的同时保证清晰显示血管情况。

Objective To assess the effect of monochromatic images and metal artifact reduction (MAR) on the image quality of spectral CT portal venous angiography in patients with operation of after the performing transjugular intrahepatic portosystemic stent shunt(TIPS) and embolization. Methods From December 2017 to April 2018, the examination data of 28 patients with portal hypertension due to cirrhosis who underwent portal vein angiography 1 month after TIPS and embolization were prospectively collected. After spectral CT scanning in revolution CT, the monochromatic energy levels(60 keV, 120 keV), 60 keV + 120 keV, 120kV-like + 120 keV fused images combined with MAR algorithm were reconstructed. Quantitative parameters such as image artifact index (AI) and qualitative visual evaluation scores were recorded and compared. Results The 120 keV monochromatic images showed the lowest AI value(30.8±8.5, 18.2±4.3) and highest metal artifacts reduction effect. The 60 keV monochromatic images showed the highest AI value (57.3±15.7, 32.1±7.9) and the lowest metal artifacts reduction effect. The AI value of 60 keV + 120 keV fused images was lower than that of 60 keV images(26.2%, 24.7%). The difference of AI value between each group was statistically significant(all P<0.05). The interobserver agreement in the subjective image scores was moderate with kappa value of 0.824. The overall image quality score of 60 keV + 120 keV fused image and the noise score of 120 kV-like+120 keV were higher than the remaining groups. The differences of the subjective scores among each group were statistically significant(all P<0.05). Conclusion The spectral CT with MAR algorithm can effectively improve the image quality of portal vein angiography after the TIPS and embolization therapy and the 60 keV + 120 keV fused images can eliminate artifacts and ensure a clear display of blood vessels.