紫绀型先天性心脏病患儿脑组织磁共振波谱研究

摘要

目的 应用氢质子磁共振波谱(1H-MRS)技术评估紫绀型先天性心脏病患儿脑代谢的变化.方法紫绀型先天性心脏病患儿29例,按不同的血氧饱和度(SaO2)分为紫绀组14例(SaO2为76% ～ 85%)、严重紫绀组15例(SaO2为65% ～ 75%);另选血氧饱和度正常、年龄性别相匹配的对照组儿童30例.应用场强为1.5T超导型磁共振扫描仪分别对这些儿童的右侧基底核区(感兴趣区20 mm × 20 mm × 20 mm 范围)进行氢质子磁共振波谱图像采集.检测指标为N-乙酰天冬氨酸(NAA)、乳酸(Lac)和肌酸(Cr),计算并比较紫绀型先天性心脏病患儿与对照组儿童、严重紫绀组与紫绀组患儿之间的NAA/Cr和Lac/Cr比值的差异.采用SPSS11.0统计软件进行统计分析.结果 紫绀型先天性心脏病患儿的NAA/Cr比值显著低于对照组(P ＜ 0.05),而Lac/Cr比值则明显高于对照组(P ＜ 0.001),差异均有统计学意义.严重紫绀组患儿的NAA/Cr比值也较紫绀组低(P ＜ 0.001),而Lac/Cr比值则较紫绀组高(P ＜ 0.001),差异均有统计学意义.结论 紫绀型先天性心脏病患儿脑组织存在NAA及Lac代谢异常,其改变程度与缺氧严重程度相关,提示慢性缺氧影响紫绀型先天性心脏病患儿的脑代谢.这将有助于阐明紫绀型先天性心脏病患儿脑功能障碍的发生机制,为早期诊断、及时干预,进而提高这些患儿的远期生活质量提供理论依据.%Objective To investigate the brain metabolism in patients with cyanotic congenital heart disease (CHD) by 1H-magnetic resonance spectroscopy (1H-MRS). Methods Twenty-nine patients with cyanotic CHD were divided into two groups according to their SaO2, cyanotic. group ( 14 patients, SaO2 76％ - 85％ ) . severe cyanotic group (15 patients , SaO2 65％ - 75％). Thirty children with normal SaO2 were used as the control group. The 1H-MRS images of region of interest ( ROI) , at the right basal ganglia (area range 20 mm × 20 mm × 20 mm) , were detected using 1.5T superconductive MRI. N-acetyl aspartate (NAA) , lactate (Lac) and creatine (Cr) were detected. The ratios of NAA/Cr and Lac/Cr were calculated for comparing the differences between cyanotic CHD patients and controls.and between severe cyanotic group and cyanotic group. Results Compared with control group, the ratio of NAA/Cr was significantly lower (P ＜ 0.05) and the ratio of Lac/Cr was significantly higher (P ＜ 0.001) in cyanotic CHD patients. Compared with cyanotic group, the ratio of NAA/Cr was significantly lower (P ＜ 0.001) and the ratio of Lac/Cr was significantly higher (P ＜ 0.001) in severe cyanotic group. Conclusions The metabolism of' NAA and Lac were abnormal in brain in patients with cyanotic CHD and was related to the extent of hypoxia. It is suggested that the chronic hypoxia affect brain metabolism in patients with cyanotic CHD. This will help clarify the pathogenesis of brain dysfunction in patients with cyanotic CHD , and provide theoretical basis for early diagnosis , prompt intervention and improvement of the long-term quality of life.