苯丙酮尿症儿童脑部磁共振成像与临床生化的相关性

目的探讨苯丙酮尿症（PKU）患儿临床及生化与MRI异常改变的关系,评价常规MRI在PKU脑部病变中的价值。方法经临床生化证实为PKU患儿12例。其中4例为新生儿筛查证实,其后接受正规低苯丙氨酸（Phe）饮食治疗;8例未经任何治疗。12例均接受1.5TMRI扫描仪头部检查,应用T2WI、T1WI序列,且对T2WI上异常高信号进行分级,与智商（IQ）、血Phe质量浓度进行相关分析。结果未经治疗的PKU患儿均表现为脑白质T2WI异常高信号,呈斑片状、对称性分布,见于顶枕部脑室周白质。代表白质病变严重程度的MRI分级与血Phe质量浓度（r=-0.537 P〉0.05）及IQ（r=-0.279 P〉0.05）无相关性;血Phe质量浓度与IQ值亦无相关性（r=0.412 P〉0.05）。结论PKU患儿IQ低或血Phe高与常规T2WI上的异常范围并不成正比;常规MRI可很好显示PKU脑部病变,能为临床诊断及监控治疗提供帮助。

Correlation of Conventional Magnetic Resonance Imaging and Clinical Biochemistry of Brain Lesion in Children with Phenylketonuria

Objective To explore the relationship between clinical,biochemistry and abnormal change of magmetic resonance imaging(MRI) in children with phenylketonuria(PKU),and evaluate the role of conventional MRI in the study of brain lesions in children with PKU.Methods Twelve patients with PKU confirmed by clinical and biochemical examination were involved in this study.All 12 patients received cranial MRI under the 1.5T MRI system with spin-echo T2-weighted sequence.The abnormal changes in white matter(WM) were graded by the extension and severity on T2-weighted images,and the correlative coefficient was calculated to investigate the relationship between MRI score and intelligence quote(IQ) as well as serum phenylalanine(Phe) concentration at the time of MRI.Results Patchy areas of increased signal intensity were demonstrated on T2-weighted images in all untreated PKU.Those abnormalities usually located symmetrically in the parieto-occipital WM.No significant correlation was found between MRI grade and blood Phe concentration(r=-0.537 P>0.05) or IQ(r=-0.279 P>0.05) and no correlation was found between blood Phe concentration and IQ(r=0.412 P>0.05) too.Conclusions The decreased IQ value or the eleva-ted blood Phe concentration has no significant correlation with the abnormalities on conventional T2WI images in children with PKU.The brain lesions in PKU can well be displayed by conventional MRI,which is helpful for clinical diagnosis and therapeutic following.