钙化磁共振信号演变规律的实验研究

Experimentalstudy of MRIsignalchangesofcalcification

目的 探讨钙化ＭＲＩ信号的演变规律并解释其形成机理。方法 采用实验的方法对钙盐标本进行研究。对碳酸钙（ＣａＣＯ３）、二水磷酸氢钙（ＣａＨＰＯ４·２Ｈ２Ｏ）、磷酸三钙［Ｃａ３（ＰＯ４）２］ 、二水硫酸钙（ＣａＳＯ４·２Ｈ２Ｏ）、氢氧化钙［Ｃａ（ＯＨ）２］ 粉末，它们不同浓度的凝胶、０－４ ｇ／ｍｌ 浓度下Ｃａ３（ＰＯ４）２／ＣａＣＯ３ 与ＣａＨＰＯ４·２Ｈ２Ｏ／ ＣａＣＯ３ 不同比例的混合物进行ＣＴ和ＭＲ扫描。各种钙盐粉末经电子显微镜观察。结果 （１） 各种钙盐的ＣＴ值随浓度的升高而增加；（２）ＣａＣＯ３ 和ＣａＳＯ４·２Ｈ２Ｏ 组标本信号强度相似，差异无显著性意义（Ｐ＞０－０５）；（３） 凝胶状态的Ｃａ３（ＰＯ４）２ 与Ｃａ（ＯＨ）２ 在ＭＲＩＴ１ＷＩ可以呈现出高信号，明显高于ＣａＣＯ３、ＣａＨＰＯ４·２Ｈ２Ｏ 和ＣａＳＯ４·２Ｈ２Ｏ 组，差异有非常显著性意义（ Ｐ＜ ０－０００ １）；（４）Ｃａ３（ＰＯ４）２ 和Ｃａ（ＯＨ）２ 组Ｔ１ＷＩ信号呈弓背向上的抛物线，在０－３ ｇ／ｍｌ 浓度信号最高；（５） 各组标本的Ｔ２ＷＩ信号均随浓度的增加而下降；（６）Ｃａ３（ＰＯ４）２／ＣａＣＯ３ 混合后其Ｔ１ＷＩ信号明显高于ＣａＨＰＯ４·２Ｈ?

Objective To evaluate MRIsignal changes according to different calcium compound, concentration and proportion,and try to give an reasonable explanation-Methods Sixty samples composed of differentcalcium powders,variousconcentration and proportion ofcalcium were examined with CTand MRI- Five differentcalcium particles were evaluated with scanning electron microscopy- Results (1) CTvalue of calcium graduallyincreased asthe concentrationincreased;(2) CaSO4·H2Owas similarto CaCO3in terms of MRIT1WI signalintensity ( P> 0-05);(3) Ca3(PO4)2 and Ca(OH)2 showed hyperintensityin T1WIand was higherthan othercalcium salts( P< 0-0001) ;(4) T1WIsignalintensity ofCa3(PO4)2and Ca(OH)2showed biphasiccurves withtheirpeaks at0-3 g/ml;(5) T2WIsignalintensity of allseries ofcalcium decreased asthe concentration increased;(6) Signalintensityof mixed Ca3(PO4)2/CaCO3 was higherthan CaHPO4·2H2O/CaCO3 on T1WIand loweron T2WI(P<0-000 1);(7) CaCO3 ,CaHPO4·2H2Oand CaSO4·2H2Oshowedregularcrystalshapesand smooth surface underscanning electron microscopy,but Ca3(PO4)2and Ca(OH)2 displayed theirirregularfigures andrough surface-Conclusions Calcificationsshow variable MRsignaldueto difference ofcalcium compounds, variousconcentration and proportion of calcium- Understanding ofthese finding will help interpretation of MR images more precisely-