Scans and More Scans -- Are We Doing the Right Thing?

F. Perry Wilson, MD, MSCE


September 04, 2019

Welcome to Impact Factor, your weekly dose of commentary on a new medical study. I'm Perry Wilson.

This week, we're talking about scans: CT scans, MRIs, ultrasounds—all those imaging modalities that tell us what's going on inside our patients.

According to a new study[1] appearing in the Journal of the American Medical Association, those scans are on the rise. Whether that is a bad thing is a bit of an open question. We'll get there, but let’s start with the study itself.

Researchers from the University of California San Francisco collated data from seven US healthcare systems and from Ontario, Canada (a unified health system), to determine how often various types of imaging studies were performed over time.

The data were pretty stark. Across all sites, in general, there has been an increase in the use of CT, MRI, and ultrasound from 2000 to 2016. These increases were seen across the US and even in Canada, ye panacea of universal healthcare.


Digging a bit deeper, there were a few interesting quirks in the data.

The rate of CT scans in children actually decreased over time.


I'm speculating here, but this may be due to increased awareness of the potential consequences of ionizing radiation exposure. Nuclear medicine scans decreased as well for reasons that I'll admit are not entirely clear to me, but I'm hopeful that you all can enlighten me.


But still, what we have overall is a study showing a pretty dramatic increase in the rate of ordering imaging for patients—crossing multiple health systems, two countries, and a few different payment models. This, despite efforts like the Choosing Wisely campaign, designed to curb utilization of procedures like this.

My reflex here was to shake my head and lament the state of a healthcare system where we no longer really think and just reflexively order imaging tests.

But then I thought about Star Trek.

Yup, Star Trek. See, in Star Trek, 100% of patients get advanced imaging. Sure, it's with a tricorder, but they get it as soon as they walk into sick bay. And Dr Crusher never wrings her hands about the slow death of the physical exam.

What's the harm of imaging? Basically, there are three things. First, exposure to ionizing radiation—in the case of CT scans, at least. Second, cost. And third, the discovery of incidental findings that lead to further workup and stress. These are real harms and things we should worry about, but we should also realize that these harms may be changing over time.

New CT protocols reduce radiation exposure. Costs are somewhat more contained under current payment models. We're probably still too defensive regarding incidentalomas, but the point is that as risks decrease, we'd expect utilization to increase.

Why? Because imaging tests are really useful. Not for everyone, and not always, but it's hard to deny that you get useful information from these tests.

The most successful way to avoid the radiation, cost, and anxiety of imaging exams, in my opinion, is to give doctors enough time to actually talk about the risks and benefits with their patients. Time with patients is more valuable than the highest Tesla MRI, but try to convince insurance companies to see that.


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