Briefly run on the top left ledge then perform a last-frame jump to barely touch the item and then fall. It is best not to moon-walk back against the wall and instead press against it and then turn around to be 1 pixel away. A wall-jump check as Samus is close to the item can expand her hitbox and make it possible from either pixel. Note that this strat is also possible on the right side of the room, but is tighter and requires backing up against the wall.