Long-term changes of magnetization transfer-derived measures from patientswith relapsing-remitting and secondary progressive multiple sclerosis

BACKGROUND AND PURPOSE: For cases of multiple sclerosis (MS), magnetization transfer (MT) imaging may provide more pathologically specific and accurat e estimates of the disease process than does conventional imaging. In this study, we evaluated changes of the MT ratio (MTR) of newly enhancing lesion s, the MTR of normal-appearing white matter (NAWM), the average lesion MTR, and the MT histogram-derived metrics during a 3-year follow-up period for patients with relapsing-remitting or secondary progressive MS. METHODS: Dual-echo, conventional spin-echo, and MT images were obtained fro m seven patients with relapsing-remitting MS, seven patients with secondary progressive MS, and five age- and sex-matched control subjects at the time of study entry and 1, 13, and 37 months later. RESULTS: Newly enhancing lesions in the patients with secondary progressive MS presented a more severe and significant MTR reduction during the follow -up period as compared with those in the relapsing-remitting group. In case s of secondary progressive MS, we also observed a significant reduction of the MTR values of the NAWM and a trend toward reduction of average lesion M TR values. The patients with MS had mean percentage changes of MT histogram -derived measures that were approximately two to 10 times higher than those of the control subjects. CONCLUSION: This preliminary 3-year follow-up study shows that newly enhanc ing lesions and NAWM in patients with secondary progressive MS have signifi cantly lower MTR values than do those in patients with relapsing-remitting MS, It also shows that the tissue damage that remains after enhancement cea ses is more severe in secondary progressive disease.