title: Automatic correction of dental artifacts in PET/MRI.
abstract: A challenge when using current magnetic resonance (MR)-based attenuation correction in positron emission tomography/MR imaging (PET/MRI) is that the MRIs can have a signal void around the dental fillings that is segmented as artificial air-regions in the attenuation map. For artifacts connected to the background, we propose an extension to an existing active contour algorithm to delineate the outer contour using the nonattenuation corrected PET image and the original attenuation map. We propose a combination of two different methods for differentiating the artifacts within the body from the anatomical air-regions by first using a template of artifact regions, and second, representing the artifact regions with a combination of active shape models and k-nearest-neighbors. The accuracy of the combined method has been evaluated using 25 [Formula: see text]-fluorodeoxyglucose PET/MR patients. Results showed that the approach was able to correct an average of [Formula: see text] of the artifact areas.
authors.affiliation: University of Copenhagen , Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, Blegdamsvej 9, Copenhagen 2100, Denmark.
authors.forename: Claes N
authors.initials: CN
authors.lastname: Ladefoged
authors.affiliation: University of Copenhagen , Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, Blegdamsvej 9, Copenhagen 2100, Denmark.
authors.forename: Flemming L
authors.initials: FL
authors.lastname: Andersen
authors.affiliation: University of Copenhagen , Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, Blegdamsvej 9, Copenhagen 2100, Denmark.
authors.forename: Sune H
authors.initials: SH
authors.lastname: Keller
authors.affiliation: Center for Medical Physics and Biomedical Engineering , General Hospital Vienna, 4L, Waehringer Guertel 18-20, Vienna 1090, Austria.
authors.forename: Thomas
authors.initials: T
authors.lastname: Beyer
authors.affiliation: University of Copenhagen , Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, Blegdamsvej 9, Copenhagen 2100, Denmark.
authors.forename: Ian
authors.initials: I
authors.lastname: Law
authors.affiliation: University of Copenhagen , Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, Blegdamsvej 9, Copenhagen 2100, Denmark.
authors.forename: Liselotte
authors.initials: L
authors.lastname: Højgaard
authors.affiliation: University of Copenhagen , Department of Computer Science, Universitetsparken 5, Copenhagen 2100, Denmark.
authors.forename: Sune
authors.initials: S
authors.lastname: Darkner
authors.affiliation: University of Copenhagen , Department of Computer Science, Universitetsparken 5, Copenhagen 2100, Denmark.
authors.forename: Francois
authors.initials: F
authors.lastname: Lauze
keywords: PET/MRI; attenuation correction; dental fillings; inpainting; metal artifacts