甲状腺结节内出血的能谱CT特征

Spectral CT Features of Intra-nodular Hemorrhage of Thyroid Nodules

目的:通过分析甲状腺结节内出血的能谱CT表现,探讨甲状腺结节内出血的能谱CT特征,并进一步讨论其价值以及甲状腺结节内出血的能谱成像原理。方法:收集18例病灶内发生出血新鲜甲状腺结节手术标本以及12例在体甲状腺结节内出血的患者进行能谱CT扫描。通过GSI-viewer软件进行图像分析,分析的参数包括:①在碘和水基物质图像上同时测量出血、病灶实性成分及周围甲状腺组织的碘和水的密度数据;②在能谱图像上(40keV到140keV)获得出血、病灶实性成分及周围甲状腺组织的CT能谱曲线,并计算各个感兴趣区的CT能谱曲线的斜率,斜率计算方法为:取40keV及100keV两点连线,与横坐标轴的角度计算,即斜率=(HU40keV-HU100keV)/60;③在有效原子序数图像上测量并分析出血、病灶实性成分及周围甲状腺组织的有效原子序数;④在65keV图像上测量并分析出血、病灶实性成分及周围甲状腺组织的CT值。结果:①病理结果:本组离体及在体的病灶中,离体组标本中其中14个结节为腺瘤伴出血,4例为结节性甲状腺肿伴出血,而在体组甲状腺结节中8例为腺瘤伴出血,4例为结节性甲状腺肿伴出血。②统计分析:经检验在体组和离体组结节内出血、病灶实性成分及周围甲状腺组织(背景)的碘浓度、水浓度、能谱曲线斜率、有效原子序数及CT值差异均无统计学意义(P>0.05),在体组和离体组病灶内出血与背景、出血与病灶实性成分的碘浓度、水浓度、有效原子序数及能谱曲线斜率差异有明显统计学意义,而在CT值的比较中,在体组及标本组的出血与实性、出血与背景的差异无明显统计学意义,将两组合并分析,出血与病灶实性成分的CT值差异无明显统计学意义。结论:甲状腺结节内的出血在能谱CT上具有特征性表现,表现为低碘含量、高水含量、低有效原子序数及低CT能谱曲线斜率。

Purpose： To study the spectral CT imaging characteristics of intra-nodular hemorrhage of thyroid nodules and its value on diagnosis of thyroid nodules. And further to explore the principles of spectral imaging. Methods： Twelve patients and eighteen fresh thyroid specimens who had intra-nodular hemorrhage of thyroid nodules underwent CT scans with Gemstone Spectral Imaging （GSI） scan mode before pathologic examinations. These images were reviewed with the GSI-viewer analysis software. The measurements included： （Ⅰ） The iodine and water contents of intra-nodular hemorrhage and solid part of thyroid nodules and surrounding thyroid tissues in material decomposition images; （Ⅱ） The characterization of the spectral HU curve （CT number as function of photon energy） for intra-nodular hemorrhage and solid part of thyroid nodules and surrounding thyroid tissues by calculating the slopes of the curves. The slope was calculated as the CT value difference at two energy levels （40keV and 100keV） divided by the energy difference （60keV） from the spectral HU curve： Slope=（HU40keV-HU100keV）/60; （Ⅲ） The effective atomic number （Effective-Z） of intra-nodular hemorrhage and solid part of thyroid nodules and surrounding thyroid tissues; and （Ⅳ） the CT value in 65keV of intra-nodular hemorrhage and solid part of thyroid nodules and surrounding thyroid tissues. Results： Pathologic results： There werel4 thyroid adenomas specimens and 4 nodular goiters specimens were confirmed with intra-nodular hemorrhage. Eight thyroid adenomas nodules and 4 nodular goiters nodules were confirmed with intra-nodular hemorrhage. Statistical analysis： There was no statistical significant difference of iodine content, water content, Effective-Z, slope of spectral curve and CT value between group specimens and group in-vivo in solid part of nodules, surrounding thyroid tissues and intro-nodular hemorrhage （P〉0.05）. There were statistical significant differences of iodine content, water content, Effective-Z and slope of spectral curve between intra-nodular hemorrhage and solid part of thyroid nodules, intra-nodular hemorrhage and surrounding thyroid tissues both in group specimens and group in-vivo （P〈0.05）. But there was no statistical significant differences of CT value between intra-nodular hemorrhage and solid part of thyroid nodules, intranodular hemorrhage and surrounding thyroid tissues both in group specimens and group in-vivo （P〉0.05）. There was no statistical significant difference between intra-nodular hemorrhage and solid part of thyroid nodules in group specimens combined with group in-vivo （P〉0.05）. Conclusion： There were characteristic manifestations of intra-nodular hemorrhage in Spectral CT imaging, which were low iodine content, high water content, low slope of spectral curve, and low effective atomic number and relatively high CT value.