Patient motion distorts the image in diagnostic CT scans, most commonly in stroke, dementia, trauma and paediatric patients; indeed young children often require general anaesthesia to avoid motion artifacts. Although scanner manufacturers have invested heavily in developments to reduce scan time and the probability of motion, if motion does occur there is still no remedy other than to repeat the scan, which also subjects the patient to a repeat radiation dose. This is especially problematic for children due to their much higher radio-sensitivity.
Having recently developed an effective method of correcting for rigid head motion in clinical helical CT scans, we are able to restore the image in all but extreme motion cases. The method can be applied retrospectively to scans acquired with standard scanning procedures. Our aim in this project is to use a variety of strategies to reduce the processing time (from up to 15 hours) to a practical level, so that motion correction, with its improved image clarity, can become a routine procedure in clinical CT imaging.