The American Academy of Neurology has set new guidelines for correctly diagnosing most strokes, recommending a type of MRI over a CT scan. The study, a literature review of MRI and CT studies going back to 1966, was published in the academy’s journal, Neurology. The story, however, does not make it clear how much better the MRI performs nor how much a switch to MRIs nationwide would cost. It does do a good job, though, of finding voices critical of the practicality of such a switch.
Strokes are among the leading causes of death and injury, although this story doesn’t point this out. Correctly assessing a stroke can make a big difference in how someone is treated and whether a future stroke is prevented. At the same time, MRIs typically cost more and take longer than CT scans. To show whether they are worth the additional time and money, reporting about these new guidelines needs to quantify the benefits, potential harms and costs.
There is no mention in this story of costs, which is a shame. CTs are the preferred diagnostic tool right now and, apparently, are widely used. A switch to MRIs would not only mean the purchasing of a lot of new equipment but also staff training, new protocols and new drugs and dyes to be administered. Are we talking about an extra $1,000 per person? $5,000? More? The reporter spoke with two local medical institutions and could have asked both of them what it costs to buy both sets of equipment and what it costs to administer the exams.
There are considerable benefits to be had, presumably. Because the number of patients is so huge, even a small improvement over present diagnositic techniques could have a big impact. As the study itself points out, "Presently, the only specific, approved therapy for acute ischemic stroke is IV tissue plasminogen activator (tPA) given within 4.5 hours. tPA use has been limited due to the short treatment window, concerns about the limitations of CT-based diagnosis, and fear of hemorrhagic risks." Does the story get into this, though? No. There is no attempt to quantify the benefits.
There is almost a throw-away line in the study that says, " A recent study estimated the epidemiologic impact of DWI-based diagnosis would result in reduced annual TIA incidence (33%) and increased stroke incidence (7%) in the United States." Reducing these "mini-strokes" by 33% would indeed be a dramatic change, given the number of people who suffer from them, but these are "warning strokes," that can actually force people to change risky behaviors or begin taking the right medications to avoid an actual stroke. Those strokes may have actually climbed by 7% in the theoretical model of a world where diffusion scans were the norm. A 7% increase in strokes could mean an additional 55,650 people suffering a stroke each year, by our count. Again, these numbers would be nice to see in the story.
Stating that something "is superior" and "is considerably better" is not quantifying potential benefits. The study itself spends little time on the numbers, but the numbers are there. And the reporter could have asked the authors to go through the numbers. There is no evidence presented that a strategy that starts with MRI has better outcomes than a strategy started with a CT. The guideline expert implies that it is obvious. The other doctors question that, but never explicitly in terms of outcomes. That’s where this story really falls short.
Not applicable. There was no disease mongering in this story because the scope of the disease was never explained. As the actual study states, "Stroke is the third leading cause of death and the leading cause of permanent disability and disability-adjusted loss of independent life-years in Western countries." So a better way of diagnosing a stroke could have a huge impact. That sort of context should have been in the story.
The story does use some independent sources, but it does not identify conflicts of interest. Again, this is a big missed opportunity because the authors of this paper have potential conflicts. They have worked with many drug and device makers, including Siemens, one of the big MRI makers, as well as: Boehringer Ingelheim, ImaRx Therapeutics, Photothera, Cerevast, CoAxia, Sanofi, Solvay Pharmaceuticals, GlaxoSmithKline, Wyeth, Genentech, LifeCycle Pharma A/S, ReNeuron, Novovision, NeuroLogica Corporation, Avanir Pharmaceuticals, Micromedex, AstraZeneca, Bayer Schering Pharma, Takeda Pharmaceutical Company Limited, Embrella Cardiovascular, Millennium Pharmaceuticals, Novo Nordisk, Otsuka Pharmaceutical Co., Pfizer, Mitsubishi Tanabe Pharma Corporation, PDL BioPharma, Inc., Terumo Neurovascular Monitoring, Guidant, Cordis, Bard Peripheral Vascular, Inc., Abbott, Boston Scientific, Olea Medical, Lantheus Medical Imaging, and, believe it or not, even more. Two hold patents on MR devices. Might they stand to beneft?
This should have been the entire point of the story, but there is really no comparison. Just broad statements made about MRIs being superior, etc.
This is something that the story really should have done high up. Why has it become standard practice to do a CT scan and not an MRI? One of the authors says that 40% of his time is spent giving MRIs and 40% doing CT scans. Is that typical? Nonethless, we’ll give it the benefit of the doubt.
The story makes it clear that both approaches are available (and therefore not new), but it should have made it more clear how rare (or not) diffusion MRI is.
There is a press release, but this story goes beyond the release.
Systematic, Criteria-Driven
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