MR扩散加权成像和波谱联合应用诊断肝豆状核变性

Combined application of MR diffusion-weighted imaging and spectroscopy in patients with hepatolenticular degeneration

目的通过MR扩散加权成像(diffusionweightedimaging,DWI)和MR波谱(MRspectroscopy,MRS)分析肝豆状核变性的表观扩散值(apparentdiffusioncoefficient,ADC)和不同代谢物的变化,探讨病变不同时期铜沉积过程出现的病理改变与MR功能成像改变之间的关系。方法对12例临床确诊并行驱铜治疗的肝豆状核变性患儿行MR常规扫描、DWI和波谱分析,比较扩散信号、ADC值和不同区域的N乙酰天门冬氨酸(Nacetylaspartate,NAA)/肌酸(Creatine,Cr)、胆碱复合物(Choline,Cho)/Cr比值的变化。结果根据DWI信号,分高、等、低3组,ADC值差异有统计学意义(F=2444,P<0001),DWI呈低信号的ADC值最高[(150±018)×10-3mm2/s],与其他两组差异有统计学意义(P1,3=000057;P2,3=000058)。MRS示NAA/Cr均值降低(108±065),Cho/Cr均值升高(133±094)。3组在基底节的NAA/Cr、Cho/Cr的比值差异没有统计学意义(F=02,11;P=08,03)。但NAA/Cr较丘脑有显著降低(t=-474,P<0001),Cho/Cr差异无统计学意义(t=145,P=016)。结论ADC值增高反映出铜沉积后局部结构疏松,海绵状变性和坏死伴随的髓鞘脱失引起的水分子扩散加快,MRS同时反映出该区神经细胞消失(NAA的降低)和星形胶质细胞广泛增生(Cho的升高)。二者的结合应用反映了肝豆状核变性过程中的微观结构变化和?

Objective To study the combined application of MR diffusion-weighted imaging (DWI) and spectroscopy in patients with hepatolenticular degeneration. Methods DWI and proton MR spectroscopy were performed in 12 cases with hepatolenticular degeneration proven by clinical symptom and ceruloplasmin. The signals on DWI, ADC value, and relative ratio of NAA/Cr and Cho/Cr in caudate and lentiform nucleus with thalamus were compared. Results Three groups were classified according to the signals on DWI including hyperintensity, hypointensity, and isointensity. ADC values had significant differences among the three groups (F=24.44, P<0.001), and it was the highest in the group of hypointensity lesions [(1.50±0.18)×10^-3 mm2/s]. However, the ratio of NAA/Cr and Cho/Cr in basal ganglia had no differences among the three group (F=0.2,1.1; P=0.8,0.3). The ratio of NAA/Cr in the basal ganglia was reduced compared with that in the thalamus (t=-4.74, P<0.001), but the ratio of Cho/Cr had no differences(t=1.45, P=0.16). Conclusion Visible increase of ADC value reflects acceleration of water molecule motion owing to spongy softening, cavitation, and demyelination. Simultaneously, MR spectroscopy demonstrates reduction in NAA, indicating the neuronal loss. Increase of Cho indicates extensive proliferation of astrocytes. Combined application reveals the changes in microcosmic structure and abnormity of focal metabolite in hepatolenticular degeneration.