Of course, no one would dispute ordering a CT for a trauma patient if the presentation warrants.

But the article was talking about the increase in CT usage over the past 20 years. That's largely been driven (in the US) by misaligned incentives that reimburse procedures at much higher rates that clinical decision making. Put simply, the person who owns the CT machine makes much more than the doctor who interprets the results. And so we have had a blossoming of imaging centers, and CT machines have moved into outpatient cardiology and even family care practices.

One of the major goals of Obamacare is addressing these misaligned incentives and shifting to a model where providers are paid to keep people healthy (outcome driven) rather than on volume (fee for service).

Another issue has been the difficulty of sharing/accessing existing imaging data, so tests are just repeated to save time (rather that save cost or adequately balance safety). Our long, painful journey to electronic record standardization should also help with that.

CT is also simply more available, so it's an option. In the past, not so much.

The doctors are doing a risk/benefit analysis: the risk is to the patient and the benefit is to their wallets. It's a no brainer.

Everyone likes to shit on lawyers, but US doctors routinely take on, and fail to disclose, conflicts of interest that would get a lawyer disbarred in a heartbeat.

Unfortunately, there is another external factor playing into the risk/benefit analysis that I haven't seen mentioned hear yet - the threat of legal action. With such low barriers to filing a malpractice lawsuit and such high payouts for "victims" and devastating effects for doctors, CT scans are often ordered for the sole purpose of mitigating legal risks.

For example - someone comes into the ER with simply a headache. On its own this should not warrant a CT scan. But if a doctor does not order one, and that patient leaves and eventually comes back with a brain tumor (extremely small odds, but not zero), then the following malpractice suit would almost certainly result in a plaintiff victory and the end of a doctor's career.

Malpractice is a real thing and real victims deserve their due. But lawyer attack ads and no limits on "pain and suffering" payouts (often multi-millions) I believe are a critical part of the difficult healthcare situation in America that continues to go unaddressed.

Except an MRI scan is just as good, but doesn't expose you to radiation. The problem is CT scans are slightly cheaper, so the insurance companies won't pay for an MRI.