Purpose: To evaluate the use of magnetization transfer and the apparent enhancement of lesions on contrast-enhanced MR images in patients with multiple sclerosis.
Methods: Contrast-enhanced T1-weighted spin-echo MR images obtained in 20 patients with relapsing-remitting multiple sclerosis, with and without magnetization transfer, were evaluated to determine the number of enhancing plaques. Comparison was made with unenhanced T1-weighted magnetization transfer images. Contrast-to-noise ratios were obtained for these lesions on both the enhanced and unenhanced magnetization transfer T1-weighted spin-echo MR images.
Results: Ten plaques were considered enhancing only when the enhanced magnetization transfer T1-weighted images (11% or more) were used; however, they were all hyperintense on unenhanced T1-weighted magnetization transfer images. The contrast-to-noise ratios of these lesions were 16.52 for the enhanced images and 15.65 for the unenhanced images. The two values were not statistically different.
Conclusions: In patients with multiple sclerosis, examination with contrast-enhanced magnetization transfer MR images alone may overestimate the number of enhancing plaques.