在脑成像检查领域中出现新的进展,使我们可以对患者进行早期的治疗

CT血管造影技术对脑血管病的诊断,和在MS患者中进行的张力扩散MRI检查

  2002年5月6日报导─4月29日和4月30日,在美国亚特兰大举行的美国伦琴射线协会年度会议上,报导了两项研究的结果,这些结果显示了在脑部疾病成像检查中,出现的两项新的进展,它们分别是脑血管疾病CT血管造影检查,和多发性硬化症(MS)的张量发散MRI检查。

  在新闻发布会上,本文的主要作者,阿曼Khoula医院的Ashok Nath医师说:「我们现在对所有的可疑的脑血管损伤的病例,使用三维CT和最高密度投影血管造影技术进行检查。神经外科医生对这种技术的依赖性很高,他们利用成像技术,来对患有颅内动脉瘤和动静脉畸形(AVMs).的患者所进行的手术进行计划。」

  在50名经过平面CT检查确诊为颅内出血的患者中,有30名患者,和9名患者经过三维成像和最大密度投射CT血管造影技术检查,分别被确诊为颅内动脉瘤和AVMs,同时可以诊断出直径小于2毫米的动脉瘤。整个过程只需要几分钟,并且患者所暴露的放射线水平要低于数码抽象血管造影技术(DSA)检查中的暴露水平。

  虽然这项技术在检查中没有发现3个部位的血管损伤,而这些损伤最终被DSA发现,但是Nath认为,这是由于放射学家对这种技术的操作不够熟练的结果。紧接著,这项技术发现了2处被DSA检查所忽视的动脉瘤。

  在杜克大学医学中心所进行的第二项研究中,利用张量发散成像技术发现了在传统MR检查中可以见到的MS患者的异常变化,这提示这项技术可以更加准确的对疾病的严重程度进行评价。

  主要作者,Provenzale医师说:「张量扩散成像技术是一种MR成像技术,这种技术可以对脑白质结构中的水颗粒的含量和变化趋势进行『测量』。张量成像技术可以帮助我们更加准确的发现MS患者脑组织的异常,因而可以在患者出现任何症状之前,进行疾病的诊断,早期发现意味著早期的治疗。」

  Provenzale说,常规的MR成像检查的结果,不一定与患者实际的情形相关,因为它们在患者的疾病进一步发展之前都可能呈现正常的结果。而张量发散成像技术可以在不同的脑区域,在更广的范围内发现异常。

  Provenzale预测,张量发散成像技术将最终帮助我们在疾病发展的早期,发现一些退行性变化,如阿尔采默氏病等,而这段时期对疾病的治疗是有效的。现在,他的研究小组利用这种技术对Krabbe's病的研究取得了好的结果。

  他说:「如果我们对那些有发生这种疾病危险的患者,在他们生命的早期经行筛查,并且给予及时的治疗,那么与那些接受治疗比较晚的婴儿相比,他们的大脑将维持与正常的儿童相似的功能。」

New Frontiers in Brain Imaging Allow Earlier Treatment

CT Angiography Helpful in Vascular Disease, Tensor Diffusion MRI in MS

By Laurie Barclay, MD
WebMD Medical News

Reviewed by Gary D. Vogin, MD

May 6, 2002 -- Two studies presented April 29 and April 30 at the American Roentgen Ray Society's annual meeting in Atlanta highlight new frontiers in imaging brain disorders: CT angiography for vascular disease and tensor diffusion MRI for multiple sclerosis (MS).

"We are now using CT angiography with three-dimensional and maximum intensity projection in all cases of suspected vascular lesion of the brain," lead author Ashok Nath, MD, from Khoula Hospital in Oman, says in a news release. "The neurosurgeons have so much faith in the technique, they are using the images to plan surgery of patients with intracranial aneurysms and arteriovenous malformations (AVMs)."

In 50 patients with intracranial hemorrhage on plain CT, CT angiography scan with three-dimensional and maximum intensity projection accurately diagnosed 30 intracranial aneurysms and 9 AVMs, including some aneurysms as small as 2 millimeters. The entire procedure takes only a few minutes and uses less radiation than digital subtraction angiography (DSA).

Although the technique missed 3 vascular lesions later seen on DSA, Nath attributes this to the radiologist's inexperience using the new technique. Subsequently, this technique detected 2 aneurysms that had been missed on DSA.

In the second study from Duke University Medical Center, tensor diffusion imaging showed abnormalities around MS plaques seen on conventional MR, suggesting more accurate assessment of disease burden.

"Tensor diffusion imaging is a form of MR imaging that [measures] the rate and direction of water particles in the white matter structures of the brain," says lead author James Provenzale, MD. "Tensor imaging is allowing us to more accurately detect abnormalities in MS patients, which may allow us to diagnose the disease before the patient has any symptoms; early detection can mean earlier treatment."

Standard MR images do not necessarily correlate well with the patient's actual condition, Provenzale says, as they may be normal until the patient has advanced disease. Tensor diffusion imaging shows abnormalities that are more extensive and in different regions.

Provenzale predicts that tensor diffusion imaging will eventually help detect degenerative conditions, such as Alzheimer's disease, in the earliest stages when treatment is most effective. Currently, his group uses it in Krabbe's disease with good results.

"If we scan patients at risk for the disease within the first month of life, and begin treatment immediately, their brains remain more similar to those of normal children than those infants treated later," he says.

© 2002 WebMD Inc. All rights reserved.

    



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