Magnetization transfer effects in MR-detected multiple sclerosis lesions: comparison with gadolinium-enhanced spin-echo images and nonenhanced T1-weighted images.
OBJECTIVE
To define the relationship between magnetization transfer and blood-brain-barrier breakdown in multiple sclerosis lesions using gadolinium enhancement as an index of the latter.


METHODS
Two hundred twenty lesions (high-signal abnormalities on T2-weighted images) in 35 multiple sclerosis patients were studied with gadolinium-enhanced spin-echo imaging and magnetization transfer. Lesions were divided into groups having nodular or uniform enhancement, ring enhancement, or no enhancement after gadolinium administration. For 133 lesions, T1-weighted images without contrast enhancement were also analyzed. These lesions were categorized as isointense or hypointense based on their appearance on the unenhanced T1-weighted images.


RESULTS
There was no difference between the magnetization transfer ratio (MTR) of lesions as a function of enhancement. MTR of hypointense lesions on unenhanced T1-weighted images was, however, lower than the MTR of isointense lesions.


CONCLUSIONS
We speculate that diminished MTR may reflect diminished myelin content and that hypointensity on T1-weighted images corresponds to demyelination. Central regions of ring-enhancing lesions had a lower MTR than the periphery, suggesting that demyelination in multiple sclerosis lesions occurs centrifugally. In addition, the short-repetition-time pulse sequence seems useful in the evaluation of myelin loss in patients with multiple sclerosis.
Hiehle
J F
JF
Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia 19104-4283.
Grossman
R I
RI
Ramer
K N
KN
Gonzalez-Scarano
F
F
Cohen
J A
JA
D000293:Adolescent; D000328:Adult; D000368:Aged; D001812:Blood-Brain Barrier; D001921:Brain / Q000473:pathology*; D015331:Cohort Studies; D003287:Contrast Media / Q000493:pharmacokinetics; D003711:Demyelinating Diseases / Q000473:pathology; D005682:Gadolinium / Q000493:pharmacokinetics; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008280:Magnetics; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000175:diagnosis* / Q000473:pathology; D009186:Myelin Sheath / Q000473:pathology
D003287:Contrast Media; D005682:Gadolinium