Monday, November 05, 2007

Magnetization transfer imaging predicts progression of disability in MS

Author: Will Boggs, MD
Date: Wed, 31 October 2007

Magnetization transfer imaging (MTI) predicts deterioration in patients with primary progressive multiple sclerosis (PPMS), according to a report in the October issue of the Journal of Neurology, Neurosurgery, and Psychiatry.

"Abnormalities in PPMS are diffuse and occur early in the condition," Dr. Alan J. Thompson from the Institute of Neurology, London, UK told Reuters Health.

Dr. Thompson and associates investigated whether the magnetization transfer ratio (MTR), which reflects axonal loss, could predict clinical changes over one year in 31 patients diagnosed with definite or probable PPMS.

Lower MTR at baseline predicted progression of clinical symptoms, as shown by greater increases in Expanded Disability Status Scale (EDSS) and greater decreases in Multiple Sclerosis Functional Composite score (MSFC) over the course of one year, the investigators report.

Lesion MTR was least significantly decreased, followed by normal appearing white matter MTR, and the latter significantly predicted EDSS change. Whole brain MTR was the most complete predictor of the MSFC change.

Predictions of clinical progression persisted after adjustment for intrasegmental volume, the investigators say, "demonstrating that the predictive value of MT imaging is independent of atrophy effects on MTR."

"We have followed this cohort for three years and are about to submit that data for publication; they reinforce these findings," Dr. Thompson added. "We will then go on to a five-year analysis, which will also include cognitive assessment, as MTI of gray matter appears to be particularly susceptible to change."

While MTI is unlikely to have a role in the initial diagnosis of MS, Dr. Thompson noted, it "may be helpful in detecting subtle change which may provide evidence towards establishing early diagnosis."