http://www.medscape.com/viewarticle/453290

April, 2003
Rohit Bakshi, MD

The importance of neuroimaging was highlighted at many of the scientific sessions at the annual AAN meeting. These included key presentations on the use of emerging imaging technologies such as functional magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS). Investigators emphasized the role of these techniques in studying normal and disease states. Following are the neuroimaging highlights of the scientific presentations given at the meeting.

Multiple Sclerosis

Multiple sclerosis (MS) is now recognized as more than simply a disease of inflammation and demyelination in the brain and spinal cord. Recent data from MRI and pathologic studies have shown that axonal loss and atrophy are common, occur early in the disease process, and are closely related to irreversible functional neurologic and neurobehavioral impairments.[1-3] Gadolinium enhancement appears to be one factor that predicts the development of brain atrophy, suggesting a link between inflammation and subsequent tissue destruction. This link between inflammation and neurodegeneration has also been suggested pathologically.[4]

Enhancement of brain lesions in MS represents active inflammation characterized primarily by the passage of T cells through the blood-brain barrier. A wide variety of enhancement patterns can be seen in MS, including homogeneous, heterogeneous, and ring enhancement.[3] Longitudinal studies have suggested that enhancement is 5-10 times more common than overt clinical attacks or progression of disability, indicating the continuous nature of the MS disease process and the sensitivity of MRI to ongoing disease activity. However, it has not been clear to what extent the morphology of enhancement predicts disease progression or brain atrophy.

During a 3-month period, Zoron,[5] Locatelli,[6] and colleagues from the University of Trieste, Italy, used monthly brain MRI and neurologic examination to study 30 patients with relapsing-remitting MS. Patients with ring enhancement at baseline experienced a higher degree of progression of MRI lesions, brain atrophy, physical disability, and number of relapses than those with only homogeneous enhancement lesions. Multiple regression analysis taking into account all baseline clinical and MRI variables indicated that only ring enhancement predicted brain atrophy during the 3 months of observation. This study shows the value of gadolinium enhancement as a monitoring tool for determining and predicting short-term disease activity in MS.

References

1. Bermel RA, Bakshi R, Tjoa CW, Puli SR, Jacobs L. Bicaudate ratio as a magnetic resonance imaging marker of brain atrophy in multiple sclerosis. Arch Neurol. 2002;59:275-280. Abstract
2. Bermel RA, Sharma J, Tjoa CW, Puli SR, Bakshi R. A semiautomated measure of whole-brain atrophy in multiple sclerosis. J Neurol Sci. 2003:208;57-65. Abstract
3. Bakshi R, Ketonen L. Brain MRI in clinical neurology. In: Joynt RJ, Griggs RC, eds. Baker's Clinical Neurology on CD-ROM. Philadelphia, Penn: Lippincott, Williams & Wilkins;2001.
4. Trapp BD, Peterson J, Ransohoff RM, Rudick R, Mort S, Bo L. Axonal transection in the lesions of multiple sclerosis. N Engl J Med. 1998;338:278-326. Abstract
5. Zoron M, Zivadinov R, Bagnato F, et al. Ring enhancement pattern may contribute to more severe disability progression and higher disease activity in the short term in relapsing-remitting multiple sclerosis. Program and abstracts of the 55th Annual Meeting of the American Academy of Neurology; March 29-April 5, 2003; Honolulu, Hawaii. Abstract P04.083.
6. Zivadinov R, Bagnato F, Nasuelli D, et al. Ring enhancement pattern predicts short-term brain atrophy changes in relapsing-remitting multiple sclerosis. Program and abstracts of the 55th Annual Meeting of the American Academy of Neurology; March 29-April 5, 2003; Honolulu, Hawaii. Abstract S51.004.
7. Sia TC, Eyngorn I, Sullivan T, et al. The etiology of transient neurological symptoms: yield of DWI. Program and abstracts of the 55th Annual Meeting of the American Academy of Neurology; March 29-April 5, 2003; Honolulu, Hawaii. Abstract P04.112.
8. Fennema-Notestine C, Jacobson MW, Archibald SL, et al. Motor-related functional MRI abnormalities in individuals genetically at risk for Huntington's disease. Program and abstracts of the 55th Annual Meeting of the American Academy of Neurology; March 29-April 5, 2003; Honolulu, Hawaii. Abstract S29.001.
9. Gonzales McNeal M, Moore M, Zitzelberger TA, et al. Plasma homocysteine and brain volume in healthy oldest old. Program and abstracts of the 55th Annual Meeting of the American Academy of Neurology; March 29-April 5, 2003; Honolulu, Hawaii. Abstract P02.041.
10. Murthy SNK, Faden HA, Cohen ME, Bakshi R. Acute disseminated encephalomyelitis in children. Pediatrics. 2002;110(e21-1):1-7.
11. Fatemi A, Barker PB, Kossoff EH, et al. Diagnosis of acute disseminated encephalomyelitis (ADEM) with proton MR spectroscopic imaging. Program and abstracts of the 55th Annual Meeting of the American Academy of Neurology; March 29-April 5, 2003; Honolulu, Hawaii. Abstracts P04.099.
12. Ambrosini A, Garreffa G, Colonnese C, et al. Increased cerebellar myo-inositol in migraine with aura on 1H-MRS: An indication of altered CA2+ homeostasis? Program and abstracts of the 55th Annual Meeting of the American Academy of Neurology; March 29-April 5, 2003; Honolulu, Hawaii. Abstract P05.153.

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