SBIG's AO-7 Adaptive Optics uses the ST-8XEI's second CCD as an imaging CCD to collect the individual frames and software to control a tilt-tip mirror to shift the image frames so that the main CCD continuously builds up its image from the tip-tilt mirror's shifted frame positions.  Thus the corrected frames are reintegrated into the main image even as they are being collected.
According to SBIG:  "The guide star's position is read in at rates up to 40 times a second, and the tip-tilt mirror is adjusted to hold the guide star on the designated pixel for the length of the exposure. The tip-tilt mirror moves and settles to within 20% of the commanded position within a mere 10 milliseconds... one can guide at 10 frames a second on a 10th magnitude star with a 10" telescope."  The high speed tip-tilt mirror is shown here.