Even though this suggestion may at first seem intuitive and appears to be backed up through evaluation, one must consider exactly how “unnecessary” scans can be avoided and the repercussions of denying patients access that could potentially help avoid missed diagnoses.

Ultimately the balance between the costs of unnecessary testing with inherent risk to the patient must be balanced with the risk of missing a diagnosis and the opportunity to intervene in a positive way. Even though in some instances the latter cases may be few in number, for those involved the risk is real and may mean life or death.

Lead author Dr. John You is reported to have indicated that one way of reducing wait times is to “not order scans in patients who are unlikely to benefit from them”. For instance while the researchers found that CT scans of the brain were most commonly ordered for headaches, less than 2% of those scans revealed a treatable abnormality. The study suggested that “many patients with a very low pre-test probability of disease can be reassured without a scan”.

It should be remembered that it is not always possible to determine which group the patient truly belongs to despite “pre-test probability”-whether they are truly in the group that does not need the scan or in the group that does. Many of us who care for patients are keenly aware of the many shades of grey in medicine. Managing patient care is not like managing the repair of a machine. If and when a patient is refused an MRI or CT scan while other patients are provided with this access, what recourse will the patient have and what restitution will be available should the unfortunate event transpire that the “pre-test probability” was erroneous?

Over twenty years ago, when CT scanners were relatively new and not widely available, patients received their scan after referral to a specialist who would determine if the investigation was necessary. It was even proclaimed that a “CT was worth a room full of neurologists”. Now patients not only have lengthy wait times for referral to specialists including neurologists but also for the scans that were expected to improve the likelihood of a definitive diagnosis. Denying patients access to developed world standard of care is certainly one way of managing wait times but hardly seems the solution to ever increasing need or demand.

Some wait time experts are calling on doctors to do better screening and physical examination instead of sending patients for these types of scans and blame the time it takes to do a proper physical exam on the growing waits for MRI and CT. It is claimed that some doctors are referring for scans instead of doing a proper physical exam. But if the physical examination of the patient was not sufficient to make the diagnosis with certainty in many instances in the past, and CT and MRI were looked upon as a medical advancement to make a definitive diagnosis then it should not be considered an advance in medical care to eliminate this kind of investigation for selected patients based on “pre-test probability”.

With shortages of all varieties of medical doctors and nurses expected to increase in the future it is difficult to imagine where the increased human resources required for more extensive physical exams will come from and whether these are resources well spent particularly when many patients will end up needing an MRI or CT scan as well for definitive diagnosis in the end.

It is also reported that MRI use “is higher for patients who live in high-income neighbourhoods, even though it is well known that people on low incomes tend to have more health problems than the wealthy” and that “access to MRI may be influenced by factors other than clinical need alone.” This should not be surprising given the fact that many high-income earners are also highly educated and will be empowered in their own health care. Does this mean that higher income patients should be denied more MRIs or CT scans or that people on low incomes should have more?

Moving forward in wait time challenges including for diagnostics such as MRIs and CT scans, it should be remembered that the system must serve the patient. If the purpose of the wait times management is to deny patients access to care or to restrict patients’ ability to receive a timely diagnosis while simultaneously denying them other recourse then our health care system is much sicker than previously thought.

The way to bring wait times for MRIs and CT scans down is not to prevent patients from accessing the investigation that is believed to be warranted after full consideration and education regarding the options but to allow patients other mechanisms to fund their tests outside the public system. Many of them will have scans that show no treatable abnormality as the ICES study showed and they will be removed safely from the wait list without disadvantaging others waiting for publically funded care.

links to other presentations By Dr. Fullerton

• Prescription for a Better Balance