Arch Neurol. 2003 Aug;60(8):1073-81
Barkhof F, Bruck W, De Groot CJ, Bergers E, Hulshof S, Geurts J, Polman
CH, van der Valk P.
Dutch MR-MS Center, and Department of Radiology, Vrije Universiteit
Medical Center, PO Box 7057, 1007 MB Amsterdam, the Netherlands
BACKGROUND:
Various types of pathologic mechanisms in multiple sclerosis (MS) can alter magnetic resonance imaging (MRI) signals, and the appearance of remyelinated lesions on MRI is largely unknown.
OBJECTIVE:
To describe the MRI appearance of remyelinated lesions in MS.
DESIGN:
Comparison of postmortem MRI findings with histopathologic findings.
SETTING:
Brain donations from a general community.Patients Magnetic resonance images from 36 rapid autopsies yielded 161 areas that could be matched with histologic characteristics, including 149 focal T2-weighted abnormalities, with a range of signal intensities on T1-weighted images.
In a subset of 49 lesions, magnetization transfer ratio could be determined.
MAIN OUTCOME MEASURES:
An observer blinded to the MRI findings assessed the presence of remyelination using light microscopic criteria; in 25 areas, in situ hybridization was used to assess the presence of oligodendrocytes expressing proteolipid protein messenger RNA.
RESULTS:
Remyelinated areas were found in 67 lesions (42%): partial remyelination was present in 30 lesions (19%), whereas 37 lesions (23%) were fully remyelinated.
Remyelinated lesions contained enhanced numbers of oligodendrocytes containing proteolipid protein messenger RNA.
All areas with remyelination shown histopathologically were hyperintense on T2-weighted images.
Strong hypointensity on T1-weighted images was significantly associated (chi2 = 29.8, P<.001) with demyelinated and partially remyelinated lesions compared with fully remyelinated lesions.
The magnetization transfer ratio of remyelinated lesions (mean [SD], 27.6% [41%]) differed (F = 46.3, P<.001) from both normal-appearing white matter (35.2% [32%]) and demyelinated lesions (22.3% [48%]).
CONCLUSIONS:
Remyelinated lesions return an abnormal signal on T2-weighted images.
Both T1-weighted images and magnetization transfer ratio may have (limited) additional value in separating lesions with and without remyelination.