能谱CT最佳单能量成像优化甲状腺结节图像质量的研究

摘要

Objective To investigate the optimal monochromatic spectral CT for improving image quality of thyroid nodules.Methods 45 patients with histologically proven thyroid nodules underwent contrast-enhanced cervical spectral CT in the arterial and venous phases to obtain the images of 70 keV and optimal keV (Opti keV) photon energies.The image noise,contrast-to-noise ratio (CNR),and qualitative scores of the two photon energy groups in each phase were compared using Wilcoxon test.Visualization of the margin,complete or interrupted enhancing capsule,and microcalcifications of the nodules was also compared using McNemar's test.Results Of 129 thyroid nodules detected,66 were benign and 63 were malignant.The optimal energy level was 61.16±5.07 keV in the arterial phase and 61.87±4.28 keV in the venous phase.In both phases,the image noise,CNR and qualitative score of Opti keV group were significantly greater than that of 70 keV group (P=0).Visualization of the margin,microcalcifications,complete and interrupted enhancing capsules of the thyroid nodules of Opti keV group was also significantly better (P=0).Conclusion Opti keV spectral CT is superior to 70 keV for assessing benign and malignant thyroid nodules.%目的 探讨能谱CT最佳单能量成像优化甲状腺结节图像质量的价值.方法 回顾性分析经病理证实的45例129个甲状腺结节的患者,术前均行颈部能谱CT双期增强扫描,得到动、静脉期的70 keV和最佳单能量(Opti keV)图像.分别对两组图像质量进行客观评价(测量图像的噪声和对比噪声比)和主观评价(5分量表),采用Wilcoxon配对秩和检验,比较两组间的差异.并采用配对卡方检验比较两组图像在甲状腺结节的边界、结节包膜完整强化环、包膜节段性缺损(“残圈征”)、微钙化四个征象显示率的差异.结果 共检出129个结节,其中良性结节66个,恶性结节63个.动脉期Opti keV为61.16±5.07 keV,静脉期Opti keV为61.87±4.28 keV.动脉期Opti keV为61.16±5.07 keV,静脉期Opti keV为61.87±4.28 keV.动、静脉期中,Opti keV组的噪声、对比噪声比和主观评分均明显高于70 keV组(P均=0.00).Opti keV组在甲状腺结节边界、微钙化、包膜完整强化环、包膜节段性缺损四个征象的显示率均明显高于70 keV组(P均=0.00).结论 能谱CT最佳单能量成像显著提高甲状腺结节图像的主客观评价,优化图像质量,有利于甲状腺良恶性结节的鉴别.