t2 flair hyperintensity brain mrit2 flair brainflair mri braint2 hyperintensity braint2 flair hyperintensityt2 hyperintense lesion in brainincreased flair signal mri braint2 flair hyperintense lesionst2 flair hyperintense signalt2 and flair hyperintense fociwhite matter t2 prolongationmultiple t2 flair hyperintense lesions