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【medical-news】MRI spots white-matter changes in movement
11/24/2006
By: Edward Susman
http://www.auntminnie.com/index.asp?Sec=sup&Sub=mri&Pag=dis&ItemId=73598
People who suffer from idiopathic dystonia may have an underlying structural brain structure anomaly that contributes to the physical spasms that are manifest in the disorder, according to researchers from the University of South Carolina in Columbia.
Using T1-weighted diffusion tensor MRI (DTI), Dr. Leonardo Bonilha and colleagues compared the brain scans of seven patients with dystonia with those of 10 patients without the disorder. They evaluated differences in mean diffusivity and fractional anisotropy, and found white-matter abnormalities in the patients with the dystonia.
In a poster presentation at the 2006 American Neurological Association (ANA) meeting in Chicago, Bonilha explained that the findings "suggest that idiopathic dystonia is not only a functional disorder, but it is also associated with structural brain changes. Impaired connectivity and disrupted flow of information may contribute to the impairment of motor planning and regulation in dystonia."
The researchers noted that idiopathic dystonia was associated with larger fractional anisotropy values in close proximity to the insula, putamen, claustrum, precentral gyrus, and cingulate and superior frontal gyri, according to the results.
They also saw smaller fractional anisotropy values in the pallidum, parahippocampal areas, thalamus, precentral and postcentral gyri, medial and middle frontal gyri, cingulate gyrus, precuneus, cuneus, and superior temporal sulcus, said Bonhila, who is an assistant professor of neurology at the university.
Finally, "idiopathic dystonia was also associated with increase in mean diffusivity in adjacent white matter to the pallidum and putamen bilaterally, left caudate, and in subcortical hemispheric regions including the postcentral gyrus, " he added.
To find ways to treat patients with idiopathic dystonia, it is imperative to first determine the cause of the condition and possibly where in the body the triggering genes reside so that pharmaceuticals can be directed at those regions or genes, Bonilha said.
"Abnormal fractional anisotropy and mean diffusivity in patients with idiopathic dystonia indicate that abnormal axonal coherence and integrity contribute to the pathophysiology of dystonia," he explained.
For more on the role of MRI in white-matter abnormalities, check out the following presentations at the 2006 RSNA meeting in Chicago:
DTI in white-matter deficits for delayed cognitive impairments in patients who have suffered a head injury (scientific paper SSJ15-01)
DTI in malformations of cortical development, such as transmantle focal cortical dysplasia and polymicrogyria (scientific paper SSK17-09)
Optimizing fetal and neonatal MR for imaging normal and abnormal medullary vessels (education exhibit LL-PD5025)
MR perfusion and DTI of microvascular white-matter disease (scientific paper SSQ13-08)
By Edward Susman
http://www.auntminnie.com/index.asp?Sec=sup&Sub=mol&Pag=dis&ItemId=73600 我试试这篇！ 本人认领该篇，若48小时后没有提交，请其他战友自由认领 磁共振发现运动失调的患者大脑白质的改变
11/24/2006
By: Edward Susman
http://www.auntminnie.com/index.asp?Sec=sup&Sub=mri&Pag=dis&ItemId=73598
哥伦比亚南卡来诺拉大学的研究者发现，自发性张力障碍的患者可能有大脑实质结构的异常，这种异常会引起躯体痉挛，表现为运动失调。
应用T1弥散张量加权核磁共振成像（DTI），Leonardo Bonilha博士及其同事比较了7个有肌肉张力障碍的患者和10个无失调症状患者的不同。他们比较了平均弥散率和断面的各向异性，发现有张力障碍的患者存在脑白质的异常。
2006年在芝加哥举行的美国神经病学会议上，Bonilha说这个发现“表明特发性的张力障碍不只是功能失调，而是与脑实质的结构改变有关。信息的联接损害和传导中断可能会引起运动功能的减弱和张力调节障碍。”
研究者指出，特发性的张力障碍与各向异性值增大有关，结果显示这些增大的向异性值（larger fractional anisotropy values）存在于岛叶、克核、屏状核、中央前回、扣带回和前上回。
他们也发现在苍白球、海马区、丘脑、前后中央回、中脑回和中脑前回、扣带回、楔前叶、楔叶、颞上沟等处存在较小的各向异性值（smaller fractional anisotropy values），南卡来诺拉大学神经病学副教授Bonhila说。
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作者:admin@医学,生命科学 2011-06-11 17:30
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