SY-001Objects outside the patient, gown snaps and ECG electrodes, drive Sybil's risk predictions
Bartlomiej Sobieski, Jakub Grzywaczewski, Karol Dobiczek, Mateusz Wójcik, Tomasz Bartczak, Patryk Szatkowski, Przemysław Bombiński, Matthew Tivnan, Przemyslaw Biecek
Instead of only asking which pixels Sybil looks at, the authors edited the CT scans themselves, using a generative model to swap regions out for plausible healthy tissue, and watched what happened to the predicted cancer risk. Two of the regions driving predictions turned out to sit outside the patient altogether: metal snaps on a hospital gown pressed against the scanner table, and ECG electrodes stuck to the chest. In one benign case those electrodes accounted for half the predicted risk.
Evidence
interventional
Key metric
50% of predicted risk traced to ECG electrodes in one benign case