Khan's five year imaging data

Background--
Rudick showed brain parenchymal fraction declines in MS
Summers showed cognitive impairment is proportional to atrophy (MS 2008)
Khan looked at 5 years of patients treated continuously with one drug (n=608) picked (how?) 275 including 121 GA 101 high dose IFN 57 low dose IFN used SIENA technique updated in 2004 to include voxel based analysis reliable to 5 mm gaps. He threw out the first year due to known problems with "pseudoatrophy" which is due to loss of extracellular fluid. Was interested in changed in atrophy from year 2-5.
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Note that in BEYOND beta 500 , beta 250, and GA had the following amount of atrophy at year one and two: -.9(second year). I Khan study at 2 years IFN -.64, GA was -.46. In interval to year five, betaseron had -2.2, Avonex had -1.83, and GA had -1.4, controls -3.8.