AJNR. American journal of neuroradiology
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AJNR Am J Neuroradiol · Aug 1995
Characterization of multiple sclerosis plaques with T1-weighted MR and quantitative magnetization transfer.
To investigate the relationship between the appearance of multiple sclerosis lesions identified on unenhanced T1-weighted images and their corresponding magnetization transfer ratios. ⋯ Lesions isointense to white matter exhibited higher magnetization transfer ratio values than lesions that were hypointense. These findings are consistent with relative preservation of the myelin structure in the former, perhaps indicating that these lesions are predominantly inflammatory (edematous) in nature. The proportionately lower magnetization transfer ratio values of lesions that appear progressively more hypointense on T1-weighted images may reflect varying degrees of demyelination, with increasing lesion hypointensity corresponding to more breakdown in the macromolecular structure. These results suggest that T1-weighted images may be useful in characterizing the underlying pathologic substrate in multiple sclerosis plaques.
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AJNR Am J Neuroradiol · Aug 1995
Balloon test occlusion of the internal carotid artery with hypotensive challenge.
To evaluate the usefulness of provocative testing with hypotensive challenge during balloon test occlusion of the internal carotid artery before carotid sacrifice and to correlate tolerance of balloon test occlusion with clinical outcome after carotid artery sacrifice. ⋯ Balloon test occlusion with hypotensive challenge is safe, economical, and greatly increases the sensitivity of balloon test occlusion. The predictive value of a negative test is high. However, to determine the test's specificity compared with quantitative imaging, controlled trials will be necessary.