They state:
Based on data from close to 100 million patients receiving CT scans in the ED, researchers found that CT use increased by 330% between 1996 and 2007 -- most strikingly for patients presenting with abdominal and flank pain. Over the same time period, the likelihood of hospital admission after a CT scan has fallen by half, though the trend toward lower admissions has leveled off in recent years.
However one commentator states:
At our institution, the triage nurses order the CT scans before the ER doctor sees the patient. A recent patient came in one week after an auto accident and was 'triaged' for a CT of the head, cervical spine, chest, abdomen and pelvis.
The comment is frankly a bit terrifying. First the triage nurse has most likely no clue, second the cost, and third the amount of radiation.
The article ends with:
Much of the increase is probably related to changes in how doctors practice medicine and the availability of CT scanners, said lead author Kocher in a statement accompanying the study's publication. CT scans "provide lots of information quickly, and so doctors and patients see CTs as a means of arriving at diagnoses efficiently and conveniently," he said. "Couple that with the fact that CT scanners are commonly housed in or near the ED itself, and the barriers to getting the test done are lower than in the past."
Frankly it is the change in the practice as well as the concern for having missed something. So why not do a scan. It throws another set of eyes in the loop. It also increases the costs and the risks. There once was a time before CAT/MRI where listening to the patient and understanding the depths of medicine counted. Imaging is a true improvement, but it has a cost, and it is not always necessary.