TY - JOUR T1 - Evolution of Multiple Sclerosis Lesions on Serial Contrast-Enhanced T1-Weighted and Magnetization-Transfer MR Images JF - American Journal of Neuroradiology JO - Am. J. Neuroradiol. SP - 1939 LP - 1945 VL - 20 IS - 10 AU - Alex Rovira AU - Juli Alonso AU - Gracia Cucurella AU - Carlos Nos AU - Mar Tintoré AU - Salvador Pedraza AU - Jordi Rio AU - Xavier Montalban Y1 - 1999/11/01 UR - http://www.ajnr.org/content/20/10/1939.abstract N2 - BACKGROUND AND PURPOSE: Magnetization-transfer imaging is a technique that could provide indirect evidence of the characteristics of multiple sclerosis (MS) lesions. The purpose of this work was to study the evolution of MS lesions on T1-weighted MR images over time and to investigate changes in magnetization-transfer ratio (MTR) values of MS lesions with different initial appearances on contrast-enhanced T1-weighted images.METHODS: Eleven patients with relapsing-remitting MS were studied with MR imaging. The MTRs were calculated for 47 lesions that had been classified according to their appearance on contrast-enhanced T1-weighted images. Each patient was examined at four time points over a 1-year period. The MTR changes observed in the selected lesions were compared with their initial T1-weighted appearance.RESULTS: The lowest MTR values were initially found in hypointense nonenhancing lesions and in ring-enhancing lesions, with both types showing a hypointense center. Changes in MTR values were more dynamic and reversible in ring-enhancing than in hypointense nonenhancing plaques. Nodular-enhancing lesions had slightly lower initial MTRs than did isointense nonenhancing lesions.CONCLUSION: The absence or presence of contrast uptake may indicate a different pathologic basis for hypointense MS lesions on T1-weighted MR images. These differences should be kept in mind when considering T1 lesion load as a surrogate marker of disability in MS. ER -