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Scan use is up, but the value is questionable Add to ...

In recent years, there has been a steady growth in the use of imaging technologies.

Magnetic resonance imaging (MRI), computed tomography (CT) and positron emission tomography (PET) are, like the X-ray of old, terms that are now an integral part of the medical lingua franca, for patients as well as health professionals.

No diagnosis seems complete any more unless a patient is whisked off to be injected with contrast dyes or jammed into a radiation-emitting machine to get an insider's look at a body part.

In the politically charged debate regarding wait times, reducing the wait for scans was singled out as a priority area. With an influx of money, not surprisingly, has come an increase in equipment and use.

According to the Canadian Institute for Health Information, there were 419 CT scanners and 222 MRI machines operational in Canada in 2007, up from 325 and 149 respectively in 2003.

(There were also, in 2007, 13 PET scanners and 18 PET/CT scanners, but there are no comparative data on the relatively new technology.)

During that four-year period, the number of MRI exams jumped 43 per cent and CT scans 28 per cent.

But recent reports have showed wait times have come down only marginally.

Ontario, for example, injected $118-million into MRI services and doubled the number of scans performed, yet the wait can still stretch up to a year for a MRI scan.

While much energy (and cash) has been expended on improving capacity, far less attention has been paid to the appropriate use of scans. CIHI, for example, tracks volume but offers no insight on the purpose of the scans.

In a fascinating study published last year, John You of the Institute for Clinical Evaluative Sciences suggested that the technology is not necessarily being used ideally.

For example, CT scans of the brain were commonly ordered for headaches, but fewer than 2 per cent of those scans revealed a treatable abnormality.

Similarly, a lot of people with backaches now receive an MRI. The ICES study found that 90 per cent of those scans found "abnormal results," but it was unclear how useful that information was in treatment.

This suggests that the increased use of scans is being driven by factors other than medical need, such as patient demand (after all, popular medical dramas on TV leave us with the impression that scans are de rigueur for every ailment imaginable) and fear of lawsuits.

Dr. You and his team found, in a more recent study, the wealthy are far more likely to get scans than the poor, suggesting that the squeaky wheels get the scans. These findings should, once again, raise red flags about how and why we use these expensive technologies.

The reality is that scans of most healthy people would turn up some kind of abnormality, most of which would be utterly meaningless.

Yet, scans are increasingly being marketed to the worried well as an essential screening tool. That is the focus of a new report from the Canadian Centre for Policy Alternatives entitled "What's in a Scan?"

One of the report's authors, Alan Cassels, a health-policy researcher at the University of Victoria, notes that it is perfectly appropriate to use tools such as CT scans to diagnose and treat cardiac and cancer patients, "but selling heart, lung and full body scans to individuals who have no apparent symptoms or are otherwise healthy is highly controversial, almost unregulated and not condoned by professional associations of radiologists."

The report also draws attention to the fact that there are a lot of private clinics that offer these scans, and they operate in a nebulous regulatory zone and pose particular challenges to publicly funded insurance programs.

Under medicare, "medically necessary" services provided in hospitals and by doctors are covered. But 18 per cent of MRIs and 5 per cent of CT scans are now done in private clinics.

You can, in many parts of the country, pay out-of-pocket to get these tests. There are 41 MRI scanners in free-standing clinics in six provinces and 21 CT scanners in clinics in four provinces.

This confusing private-public mix raises concerns about two-tier care. You can get on a public wait list or pay and get a scan faster from a private clinic - whether your test is "medically necessary" or not.

What happens if the MRI shows, for example, torn ligaments in your knee? Do you get to jump the queue and get surgery before those waiting for a scan in the public system?

And what happens if you undergo a full-body scan that shows some abnormality in your lungs? Does the public system have to incur a host of costs to further probe something that may well be benign?

The public surely recognizes the benefits of scans but they do not always understand the downsides. The exposure to radiation during CT scans is not insignificant. Ontario's Auditor-General expressed concerns about excessive doses of radiation, particularly in children. Even an MRI - which doesn't use ionizing radiation and is generally considered a very safe procedure - can be highly unpleasant, the noise inside the giant magnet deafening.

When imaging technologies are used appropriately, these risks are far outweighed by the potential benefits.

When treating patients, the goal should always be to provide timely, appropriate, quality health care. In the case of medical imaging, we have put far too much emphasis on timeliness and not near enough on appropriateness.

apicard@globeandmail.com

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