The Analytic Age

Fortune has a brief article on aneurysm-spotting analytic software developed by IBM in collaboration with Mayo Clinic (HT to Satish Bhat for bringing this article to my attention).

To help in their aneurysm hunt, radiologists at Mayo Clinic use special software developed with IBM that analyzes a three-dimensional brain scan. Computer algorithms process information in the images, pick out abnormal areas where fragile blood vessels might be hiding, and flag the potential trouble spots for Mayo doctors. So far the results are promising. In trials the software found 95% of aneurysms; a typical radiologist would have found 70%.

95% vs 70%. How many lives saved as a result? I couldn’t find anything in the article on this question so I did some Googling.

Here’s what I found:

perhaps 25,000 to 50,000 people a year in the U.S. have a brain hemorrhage caused by a ruptured aneurysm.

Of these 25,000-50,000 people,

One-third to nearly half of patients have minor hemorrhages or “warning leaks” that later lead to a severe devastating brain hemorrhage days later.

So 8,000-25,000 people come in with a “warning leak”. Every one of their brain scans is presumably looked at by a radiologist. According to the Fortune article, radiologists have only a 70% success rate so let’s assume that 30% of the scans (i.e. 2,500 to 7,500 people) are mistakenly thought to be normal and, therefore, left untreated. They return days later with a burst aneurysm. What happens next?

The overall death rate once the aneurysm ruptures is about 40%

So, between 1000-3000 patients will die because the aneurysm wasn’t caught during the first visit.

Now, let’s look at how the analytic software will perform. According to Fortune, the software yields a 95% success rate so 5% of the scans (i.e. 400 to 1200 people) will be mistakenly thought to be normal and left untreated. Of these patients, between 160-480 patients will die (using the same 40% death rate as before).

Incremental lives saved? Between 800-2500 patients annually. Wonderful! Kudos to IBM and Mayo.

Here’s a little (hopefully) self-explanatory graphic. The blue box represents the incremental lives saved by the software; the red represents the lives that could be saved if the software’s accuracy goes to 100%.

p.s. I realize that numerous assumptions have been made in this back-of-the-envelope assessment. Feel free to criticize and improve. I just wanted to get a quick sense for how many lives would be impacted.