Functional MRI (fMRI) scans have been used for years in trying to study and to diagnose Alzheimer's in living patients. This goes back at least 16 years. Thousands of scans have been collected and used in many studies looking for a prevention or treatment of the disease. Unfortunately, a bug has been found in the software which helps interpret the scans which may cause those scans to now be unusable at worse and suspect at the least.
The software divides the brain into tiny units called voxels. It looks for clusters of voxels showing activity. The problem is that the sheer number of voxels turned out to be significantly more than the software could handle which results in false positives.
There are three different software packages involved and there's a 70% chance of at least one false positive.
The impact on patients who have been misdiagnosed is huge.
The impact on the studies relying on this data is huge.