A Mathematical Framework for MRI "Hallucinations"

Machine-learning methods are being actively developed for computed imaging systems like MRI. However, these methods occasionally introduce false, unexplainable structures in images, known as hallucinations, that can lead to incorrect diagnoses. Researchers at the Beckman Institute for Advanced Science and Technology and the Computational Imaging Science Laboratory have defined a mathematical framework for identifying hallucinations, a first step toward reducing their frequency. This work, "On hallucinations in tomographic image reconstruction," is published in IEEE Transactions on Medical Imaging in a special issue on machine learning methods for image reconstruction. Most modern medical imaging devices -- such as MRI, computed tomography, and PET -- do not record images directly.