In the not-too-distant past, a patient brought to the emergency department of a community hospital in the middle of the night with symptoms of stroke might have had to wait hours before a technician arrived to conduct a CT scan and the radiologist on call—awakened from sleep—showed up to interpret the study. In teaching hospitals, the scenario was a little different since residents were available to provide preliminary interpretations, but final reports by more seasoned radiologists were not rendered until the next morning.